Science 20 - Unit A: Chemistry
Chapter 1- Aqueous Solutions
A1.1 & 1.2 - The Structure of Matter & Atomic bonding
o
Review terms to know:
Complete the crossword below
Down
Across
2. ______________________: The subatomic particle
with a negative electric charge, located outside of the
nucleus in orbitals. More than 1,800 times smaller
than protons & neutrons, having a mass of only 9.11 x
10-28 grams.
1. __________________: Specific orbitals, in which
electrons are located, that are different distances from
the nucleus. The larger the number of the energy
level, the farther it is from the nucleus. (2)
4. ___________________: A subatomic particle
located in the nucleus of all atoms with a positive
electric charge. The number of these is always equal to
the atomic number.
5. ______________: The basic building blocks of
matter: the smallest form of an element.
3. ___________________: An electron located in the
outer most energy level (aka the valence energy level)
that is the most likely to be involved in a chemical
reaction.
6. ____________: An atom or molecule with an
electric charge due to the loss or gain of electrons.
7. _____________________:A subatomic particle with
approximately the same mass as a proton, but with
no electric charge, located in nucleus of all atoms.
8. __________________: A pure substance consisting
of only one type of atom.
Drawing Diagrams of Atoms:
1.
Bohr diagrams
o
Bohr diagrams use a series of rings to represent electron energy levels, and a circle in the middle to
represent the nucleus
o
inside the circle for the nucleus, you must list the number of protons, and the most likely number
of neutrons
o
each electron is represented by a dot •
o
to figure out how many:

rings you need around the nucleus, ____________________________________________
__________________________________________

dots you can place in each inside ring, _________________________________________
__________________________________________

dots are in the outermost (valence) shell, _______________________________________
__________________________________________

electrons that element must gain or lose as an ion, ______________________________
__________________________________________
Practice:
o
(a) hydrogen
2.
draw Bohr diagrams for the following atoms:
(b) fluorine
(c) silicon
(d) carbon
(e) helium
Lewis dot diagrams
o
Lewis Dot focuses only on the outermost (valence level), since those are the only ones capable of
undergoing reaction to form compounds

the symbol for the element represents the nucleus
 a dot (•) is still used to represent each valence elect
Drawing Lewis dot diagrams:
o write the element symbol to represent _______________________________
_________________________________
o use a dot to represent _______________________________________
o other than for H or He, each element’s valence shell has four orbitals, each of
which can hold zero, one or two electrons (for a total of up to 8 electrons)
o start by placing single valence electrons into each of the four valence orbitals
o if additional locations are required for electrons, start filling the four orbitals with a second electron,
until up to all eight positions are occupied.
o
below are the Lewis dot diagrams for the elements in period 2.
o
fill in the dots for the elements in period 3.
o
notice anything?
Atoms to Ions
o
Recall that in an atom, the number of protons and electrons are equal.
o
This means that the valence energy level is NOT necessarily full
o
Atoms are capable of gaining, losing, or sharing electrons to try to become more
stable.
o
an atom is more stable if ______________________________________
________________________
LEAST Stable
o
A full orbital can hold 8 electrons
o
 An atom will do whichever is “easiest” to achieve a full valence orbital
Metals atoms will always _____________________________ to become cations
MOST Stable
_____________________________________

o
They will join with a non-metal ion to make _____________________
______________
Non-metals will ________________________ to become anions ____________________________________

anions will combine with cations to form _________________________________ (w. ionic bonds)

Non-metals can also ________________________________electrons
 When non-metal ions share electrons they _________________________________________________
( w. covalent bonds)
Attraction between particles:
o
particles with the __________________________________________ each other, while particles with
_______________________________________________ each other
o
electrons are attracted to the positively charged protons in the nucleus of their own atom

the closer the electron is to the nucleus, the
______________________________________________
o
this is why the atom’s valence electrons, (the ones furthest from the nucleus), are
easily given away - they aren’t as closely attracted to their nucleus.

valence electrons are attracted to the positive nucleus of the other atoms
- when one atom loses electrons, another atom that has space in its
valence shell will pick them up
Try These!
 Practice Problems
 #2-5 (a,c,d,g) pg. 8 & 9
 # 6 (a,c,d,g) pg. 10

# 7 & 8 pg. 13
 A 1.1 Summary Q’s 2-6,
8 & 9 pg. 14
Review terms: Physical & Chemical properties
o Physical Properties
 an aspect of matter that can be observed or measured without changing it

__________________________________________________________

Examples:



o
Chemical Properties
 properties of matter that can only be measured by performing a chemical change

_____________________________________________________________________________________

Examples:




reaction with…
Chemical properties of metals
o
o
react with water & air: they will oxidize (aka rust)
react with acids: will produce hydrogen gas
o
metal atoms will _____________________________________________ in
order to become more stable.
 when they do this, a metal atom becomes a _______________
____________ (called a cation)

metal ions will react with non-metal ions to form ionic
compounds.
Physical properties of metals
o
state: _______________________ at room temperature (except mercury)
o
colour: most are ______________________________
o
lustre: _____________________
o
malleability: highly malleable
(_________________________________________________________________________)
o
ductility: highly malleable (___________________________________________________________________________)
o
conductively: highly conductive (________________________________________________________)
o
a solid piece of metal is formed by positive ions attracted to a see of free-moving electrons
 since like charges repel one another, the electrons act as a “buffer” (or glue) to keep all the
positively charged metal nuclei together.
 their __________________________ is what gives metals their
_______________________________________.
Chemical properties of non-metals:
o
o
o
react to form oxides that are acidic
are good oxidizing agents (which mean they take electrons from other
substances)
non-metal atoms will _____________________________________ in order
to become more stable.

when they do this, a non-metal atom becomes a _____________
_________________________ (called a ________________________)

the exception is noble gases, which already ___________________________________________ and are
already very stable
o
non-metals can either:
 react with metal ions to form ionic compounds

OR
__________________________________ with other non-metals to form _______________________________.
Physical properties of non-metals:
o
state: can be ____________________________________________________ at room temperature
o
colour: ____________________-different colours
o
lustre: - ________________
o
malleability & ductility: NOT malleable or ductile= __________________________
o
conductively: NOT conductive = __________________________________
Properties of salts
o
salts are _______________________________________________(NOT just table salt)

form a VERY _____________________________________________ between the two ions
o
 b/c the electron from sodium's valence energy level is now apart of chlorine’s valence orbital.
state: ________________________ at room temperature.
o
colour: _________________________________ as a solid. Often dissolve to _________________
__________________________________
o
malleability & ductility: NOT malleable or ductile= ____________________
o
solubility: generally dissolve well in water (_______________________)
o
conductively: not conductive as a solid. Highly conductive in solution = _________________
o
the ions are organize themselves into ________________________________________ to
o
form crystals.
 this structure is referred to as a “crystal lattice”
since like charges repel one another, the cations and anions alternate so the particles stay together.
 like metals, their arrangement is what gives them their distinctive physical properties.
Properties of plastics
o
plastics are large hydrocarbon molecules

hydrocarbon are organic compound made of carbons and hydrogens held together with ______________
__________________

Covalent bonds are ________________________________________________ b/c the _____________
_____________________________ between the two non-metals not completely transferred.
o
state: ___________________________ at room temperature.
o
colour: ___________________________-different colours
o
conductively: not conductive = ____________________________________.
o
o
plastics are __________________________________ (elastic), ________________________________
(which makes them water resistant), they can be permeable or non-permeable
Since there are no + and - ions they ______________________________________”___________________”
o
Instead, a Lewis dot diagram shows the ___________________________________ in large molecules like plastics.

like metals and salts, their _____________________________________________ is what gives them their
distinctive physical properties.
How does arrangement/ bonding explain the properties of matter?
melting point:
flexibility:
o
o
energy is required to raise the
temp. of a solid in order to make a
substance melt.
_____________________ occur
when the heat energy ___________
_______________________. of a
substance, but is ________________
______________________________
____________________________to
make them change into a liquid.

ionic bonds are VERY
strong, so ionic compounds
_________________________
_________________________


o ionic compounds are _________
_______________________b/c they
have oppositely charged ions.
 when an ionic cmpd. is bent, like
charges are forced close
together, and like charges repel,
so they internally force the
compound to push away from
itself and snap.
 molecular compounds are
___________________b/c they
do not have opposite charges,
thus the shared electrons just
migrate around each nuclei and
hold all the ions together no
matter when they are bent to.
 metals are also flexible (=
_________________
_________________ when
covalent bonds are weaker,
discussing a metal) b/c the ‘sea’
so _______________________
of _________________
_________________________
________________________
__________________b/c they
______________________ to one
do not need as much energy
another and repelling, as they do
to break apart.
in an ionic cmpd.
metals have higher melting
points than molecular
compounds, because of the
_________________________
_______________, but
generally a lower melting
point than ionic compounds.
conductivity:
o the ability to conduct electricity
depends on ____________ ___
___________________
 therefore _____________
_____________________
_____________________ b/c
they both have free electrons.
 molecular compounds are
insulators (not conductors) b/c
there are
_____________________.
Product
Atoms
Rock Salt
sodium & chlorine
Category of Matter
ionic compound
Properties
-
(_______________
bonds)
Plastic
hydrogen & carbon
molecular compound
-
(________________
bonds)
Aluminum foil
aluminium
metallic element
( ______________
bonds)
Try These!
 Practice Problems
 #11 pg. 21
 #12 pg. 23
 #7 & 8 pg. 13
 A 1.2 Summary Q’s
1 (a,b,f), 2 (c & d) 3, 5 pg. 23
A 1.3 - Aqueous Solutions
o in order for a chemical reaction to occur:
 ______________________________________________________, with new distinct properties from the reactants
 Observations: new odour, phase change, bubbles/ precipitate form, new (irreversible) colour
 a ______________________________________ (can be either endo or exo-thermic)
 Observations: heat or light produced, heat or light absorbed, (both resulting in a temperature change),
phase change
 endothermic reactions: energy is ___________________________
o Ex. _______________________
 exothermic reactions: energy is ___________________________

Ex. ____________________________________
Solutions
o solutions are homogeneous mixtures of substances composed of a _____________________________
 solvents are the substances _______________________ the solutes dissolve.


solutes are the substances ______________________ the solvents.


water is the most common solvent and forms _________________________.
Ex. in salt water: salt is the solute and water is the solvent.
both solvents and solutes can be in _______________________________________

Ex. metal alloys such as brass: copper is heated to liquid form, zinc metal is
dissolved into the molten metal, then cooled back into a solid.

Ex. windshield washer fluid, alcohol is the solute in a water solvent.
Structure of the water molecule
o
why is water such a good solvent?
o
because water is a __________________________________.
o

polar molecules attract one another (cohesion) more strongly than other
molecular compounds that are non-polar

a polar molecule has one end that has a slightly more negative charge
(oxygen) and a slightly more positive end (hydrogen).
polar substances act as good solutes for
______________________________________ and for all ___________________________________

o
the slightly negative end of the water attracts the cation (+) from the ionic cmpd. and the a slightly positive
end attracts the anion (-).
water dissolves so many substances, so easily that ___________________ (H2O)
______________________________________.
o
aqueous solutions are the most common and versatile type of solutions

all aqueous solutions are ________________(or transparent)

recall, “clear” does not mean “colourless”
Solvation
o
Solvation: the process of a solute dissolving in a solvent.

solute is added to solvent  polar water molecules attract the opposite sides of the solute particles  bonds
holding solute together break down  solute ions are separated and become completely surrounded by
solvent molecule

if the _________________________________ of the solute is ____________________________________, the
particles of the solute ______________________.The solid in a solution is called a precipitate.
Dissociation
o
Dissociation: the ________________________ that occurs when an ionic compound dissolves in water.

Ex. __________________________________________

the degree of dissociation depends on the _____________________________________________________

a compound with low solubility (e.g. calcium carbonate) is assumed not to dissociate to an significant amount
Dispersion
o
o
Dispersion: occurs when a molecular compound is dissolved in water, but it does NOT dissociate because it does
not have charged ions.

instead, it will simply _______________________ and become ________________________________ of itself.

Ex. ___________________________________________________
solutions that do not conduct are non-electrolytes.

o
molecular compounds that form solutions _______________________________________________.
Electrolytes: solutions that conduct electricity, ___________________________________________________________.

recall conductivity is the ability for free electrons to move through a substance.

all ionic compounds that form solutions conduct electricity.
o
strong electrolytes: when ___________________________________________________= _______________________,
so the solution conducts a strong electrical current
o
weak electrolytes: when ____________________________________________________ = less conduction = only a
_____________________________________
o
testing a solution for electrolytes involves the use of an ohmmeter,

uses a positive cathode and a negative anode to complete a circuit to test if electricity passes through the
solution
Water as an agent of chemical change
o using a solvent like water is a good way to facilitate a
chemical reaction

two solid ionic compounds have __________
______________________________

Solubility (review)
 combinations of these cations and anions are
highly soluble (and will form strong
electrolytes)

combinations of these cations and anions are
only slightly soluble (and will form weak
electrolytes)
by dissolving the two compounds in water
first before mixing, the number of ions
that can come in contact is much higher.
Try These!



Complete the Investigation
Practice Problems
 #17 & 18 pg. 27
 #21-23 pg. 30
 #24 pg. 31
A 1.3 Summary Q’s 5 & 6
pg. 33
Purpose:
Classify solutions as electrolytes and non-electrolytes
Predictions:
Make predictions for each solution using what you know about the different types of
compounds. Complete the predictions column of the Evidence table.
Solutes can be classified into two categories:
 electrolytes: substances that upon dissolving will conduct electricity.
 non-electrolytes: substances that upon dissolving will NOT conduct electricity.
Materials:




Electrical conductivity apparatus
500 mL waste beaker
Distilled water bottle
Misc. solutions
Experimental Design:
 Use an electrical conductivity apparatus to determine whether the substances in the material list are
electrolytes or non-electrolytes. Rinse the electrodes with distilled water after each test.
Evidence:
Chemical Name
water
ammonium acetate
cobalt (II) nitrate
ethanol
glycerol
sucrose
hydrochloric acid
sodium chloride
potassium iodide
sodium hydroxide
sulfuric acid
copper(II) sulfate
Chemical Formula
Classificati
on
(I , M or A )
Prediction
Electrolyte
 (Yes) X (No)
Observation
Electrolyte
(Yes) X (No)
Evaluation:
1. Compare your predictions with your results. Did they match? Account for any inconsistencies.
2. Explain why some substances are electrolytes while others are non-electrolytes.
3. Write a dissociation equation for each of the solutions that dissociated in water
Sample dissociation equation:
sodium chloride + water  aqueous sodium ion + aqueous chloride ion
NaCl(s) + H20(l)  Na+(aq) + Cl-(aq)
4. What generalizations can you make about the physical properties of aqueous solutions?
A 1.4 - Solutions & Concentrations
Concentration
Concentration: the _____________________ of the quantity of _____________to the quantity of
o
_____________________________

Concentrated vs. diluted
 products sold in stores are often sold in a “concentrated” form because the
product weighs less and is therefore cheaper to package and ship
a solution is said to be saturated when ___________________________________________
o
___________________________________________
Concentrations can be observed:
o

qualitatively: using the _______________________________
 observations: the colour could be darker, smell stronger, be thicker in texture



quantitatively: using values and __________________________
 observations: 5% (v/v), 5.00 g/L, 5 ppm, 5 mol/L
 When the concentration of a substance is specified, it describes the amount of solute per amount of
solution
To increase the concentration of a solution, you can either:

________________________ the first is usually done because it’s easier

________________________
To decrease the concentration of a solution, you can either:

________________________

________________________ the second is usually done because it’s easier
Concentration & Collision-Reaction theory
o
collision-reaction theory: reaction takes place because molecules collide with each other. Collision cause _________
____________________, and the rearrangement of particles to _______________________________________.
o

the ____________________________________ that occur, the ____________________the reaction will occur

a _____________________________________ solution has ______________________  _________________

heating a solution, _________________________  makes the particles ______________________ 
increases the speed they collide, speeding up the reaction.
as a result, more concentrated solution will:
 be a _______________________________
(produce a higher reading on the
conductivity meter)

_________________________________ in a
reaction
Molar concentration
o
Molar concentration: how many _____________________________________________________________
 the unit for molar concentration is mol/L
 we assume that the volume of the solvent is equal to the volume of the solution
 Ex. if you add 10.0g of salt to 1.0L of water, you get 1.0L of solution – the salt does not
significantly alter the volume of the solution.
Review of the molar mass:
o
o
each element on the periodic table has its own atomic mass.
the molar mass is the mass of an element (or compound) in grams per mole (g/mol) of that substance.
 Ex. the molar mass of carbon is 12.01g/mol. That means that one mole of carbon weighs 12.01g.
o
the molar mass of compounds can be calculated by adding up the molar masses of the composing elements
 Ex. the molar mass of water, H2O is…

MH2O = 2 (MH) + 1(MO)

MH2O = 2 (______________) + 1(______________)

MH2O = ____________________
The relationship between molar mass, number of moles and mass:
n=
o
Recall the formula:
o
Rearrange the formulas:
 To solve for “m”


~ To solve for “M”
Try These!
 Practice Problems
 #25 & 26 pg. 35
 A 1.4 Summary Q’s
2-4 pg. 39
 Moles Calculations Worksheet
Name: ________________________
Mole Calculation Worksheet
Moles, Molarity and Molecules, Oh My!!
1. Determine the molar mass (M) for the following:
a) Cr
b) O2
c) C8H18
d) Ba(OH)2
e) potassium chlorate
f) CH3COOH
g) Na2SO4
h) sulphuric acid
i) silver nitrate
A laboratory procedure requires the use of two solutions and a powdered metal.
Solution #1 contains 0.750mol of copper (II) sulfate. Solution #2 contains 0.875mol of zinc
oxide. The procedure calls for 0.100 moles of magnesium metal.
2. Determine the mass (m) of each substance required for the lab activity.
3. Calculate the number of moles (n) of the following:
a) 80.0g of H2O
b) 45.00g of C6H12O6
d) 3.9 mg of I2
(hint: 1000mg= 1g)
c) 5.5 g of sodium hydroxide
e) 23.9L of krypton gas
(hint: 1L= 1000mL, 1 mL= 1 mg, 1000mg= 1g)
A 1.5 - Calculating Concentration
Percent concentration
o
often used in consumer products, where a liquid is dissolved in a liquid
 Ex. drinks, cleaners
 symbol used  % (v/v)
o
to calculate percent by volume:

C% (v/v) = (vsolute / vsolution) x 100%

the “v/v” designation is used to distinguish this concentration from a mass per volume concentration,
which we won’t address.
rearrange the formulas:

Examples:
To solve for “vsolute”
~ To solve for “vsolution”
#1)
A 300mL bottle of hydrogen peroxide solution contains 18.0mL of peroxide. What percent concentration
is the product?
#2)
A fruit beverage advertises itself to contain 45.0% real fruit juice. What volume of real fruit juice is found
in a 2.00L jug? (Show the rearranged formula first!)
Parts per million
o
useful for concentrations where there is a _______________________________________________ in a _____________
_________________________________________
o
o
 Ex. the amount of pollutants in drinking water
symbol used  ppm
 1 ppm is equal to 1.0mg of solute per 1L (or 1kg) of solution
 Remember that 1mL of water = 1g
to calculate parts per million:
rearrange the formulas:

Examples:
~ To solve for “msolution”
To solve for “msolute”
#3)
The allowable level of fluoride in our drinking water is 1.5mg for every litre of water. How many parts per
million is the allowable level?
* Hint: 1L of water = 1000g = 1 000 000mg
#4)
In the middle of spring, pollen levels can reach 5000 ppm. What mass of pollen would you inhale if you
breathe in about 9.6g of air?
Molar concentration
o
amount of moles of solute per litre of solution, often used in labs


_______________________________________________
symbol  mol/L, also referred to as “molar”
o
standard solution: a solution having a known concentration
o
to calculate molar concentration:
where
n=m
M
rearrange the formulas:
 To solve for “n”
~ To solve for “m”
To solve for “v”
~ To solve for “M”

note about significant digits and not rounding off till the next step:
o
o
In a two-step question, you must not round off the number from step one.
Keep the unrounded number stored in your calculator for use in step two.
Examples:
#5)
What is the concentration of an acid that has 0.50mol of solid dissolved in 2.00L of water?
#6)
30.0g of sodium sulfate is dissolved in 300mL of water. Determine the molar concentration
#7)
50.0mL of a 0.200 mol/L solution of copper (II) sulfate contains what mass of solid copper (II) sulfate?
Try These!
 Practice Problems
 #28-30 pg. 42
 #31-33 pg. 44
 #34-36 pg. 46
Diluting solutions
o
a solution is diluted by adding more solvent
o
This means that the ___________________________________________ DOES NOT CHANGE

o
therefore when diluting solutions, the number of moles of solute (n) stays the same
the formula to calculate molar concentration when performing a dilution is ,
…b/c the number of moles are the same

because the ________________________________________, as long as the _______________________
__________________________, there is no need to convert them

 Ex. both in mL or both in L
because you are dealing with four different variables, you should start by making a list:

Ci
= ______________________________

vi
= ______________________________

Cf
= ______________________________

vf
= ______________________________
Examples:
#8)
#9)
50.0mL of a standard 1.00mol/L solution of hydrochloric acid is diluted to 200mL. What is the new
concentration?
50.0mL of the same standard solution is diluted to 0.05mol/L. What volume is the diluted solution?
Try These!
 Practice Problems
 #37-39 pg. 50-51
 Prepare for Investigation: Developing
Technological Skills with Solutions
 Complete pre-lab calculations
Name: ______________________________________
Group Member(s): ________________________
Use pages 46-48 in your textbook
Purpose:
You will practice the skills for making a standard solution and for making a dilute solution.
Materials:
 scale
 50-mL beaker
 2, 100-mL volumetric flask
 anhydrous copper (II) sulfate (CuSO4 (s))
 distilled water
 eyedropper
 10-mL volumetric pipette
Pre-lab Analysis:
1. Complete the following calculations to determine the number of moles of solute you will need for your solution:
C= n
V
V = 100mL x
1L____
1000mL
 V = __________________
C = __________________
n=
n=?
2. Complete the following calculations to determine the mass of anhydrous copper (II) sulfate you will need to
make your solution:
M CuSO4 (s) =
n= m
M
m=
 M = __________________
n = __________________
m=?
Procedure: Part A: Making the Standard Solution
Use the value determined in the pre-lab to make 100mL of a 0.200mol/L solution of copper (II) sulfate from
anhydrous copper (II) sulfate solid. Follow the procedure outlined on pg 47
Part B: Diluting a Standard Solution
You will make 100 mL of a new solution that is 10% of your standard solution in part A. Follow the procedure
outlined on pg 47 & 48.
Analysis:
1. a) List the potential problems you have encountered with each step of the procedure.
b) Identify steps that could affect the accuracy of the concentration of your standard solution.
c) Are you confident that your standard solution is exactly 0.200 mol/L? Support you answer.
2. Which WHMIS symbol should be placed on the solution?
3. a)
Using the formula CiVi = CfVf determine the concentration of the diluted solution.
b) Explain the importance of knowing the exact concentration of the standard solution.
4. Do you think it would be easier or more difficult to make a standard solution that is colourless? Support your
answer with an explanation.
5. Explain how volumetric flasks and pipettes help you measure volumes with great precision
Science 20 - Chapter A1 Review Worksheet
1.
Bohr diagrams
a) Draw Bohr diagrams for the following:
ia neon atom
ii - an oxide atom
b)
2.
4.
What similarities do you notice? What differences?
Lewis dot diagrams
a) Draw Lewis dot diagrams for the following:
b)
3.
iii - a sodium ion
i-
three alkaline metals
ii -
three noble gases
in each series of three, what similarities do you notice?
Using either the number of electrons or the size of the atom, explain why:
a)
fluorine is more reactive than iodine
b)
fluorine is more reactive than nitrogen
c)
francium is more reactive than radium
d)
francium is more reactive than sodium
Refer to the three diagrams below.
A
B
C
State which diagram best applies for each situation described below.
a)
the one that best represents butane, the flammable hydrocarbon in Zipo-lighters
b)
the one that involves a complete transfer of electrons
c)
the one with the most inflexible bonds
d)
the one that forms a covalent bond
e)
the two that involve a sharing of electrons
f)
the two that involve a free flow of electrons
g)
the one that could represent lithium
h)
the one that forms a crystal lattice structure
5.
Write dissociation equations for when the following compounds are dissolved in water. Remember to consider the
type of compound (ionic or molecular) and its solubility.
a)
lithium bromide
b)
calcium carbonate
c)
glucose
6.
Explain why dissolving two solids in water first before reacting them will make the reaction occur faster.
7.
Describe the easiest method for:
8.
9.
a)
increasing the concentration of a solution
b)
decreasing the concentration of a solution
For each observation below, classify it as a qualitative or quantitative observation:
a)
solution A was more cloudy than solution B
b)
solution A had 1.0mol/L more solute than solution B
c)
twice as much solute was added to solution B than to solution A
d)
solution A had a stronger odour than solution B
A bottle of nail polish remover contains 5% acetone. What volume of acetone is in a 375mL bottle?
10. A 500mL bottle of water contains 19ppm calcium. What mass of calcium does this represent? How many moles of
calcium is this?
11.
What mass of solid hydrogen chromate was needed to make 3.5L of a 0.1 mol/L solution of chromic acid?
12. 100g of lead (II) carbonate is dissolved in 1.25L of water. What is the molar concentration of the solution?
13. 100mL of a 1.0mol/L standard solution is diluted so that its total volume is now 450mL. What is its new
concentration?
14. A 4.6mol/L solution becomes half as concentrated when water is added to the solution. What happened to its
volume?
Chapter 2- The Reduction & Oxidation of Metals
2.1 - Compounds and Chemical Change
O
O
O
Archeologist studies show that ancient civilizations were not only using metals, they learned to manipulate it

metallurgy –__________________________________________________________________

by analyzing copper artifacts, archeologists use chemical analysis to track trade routes, locations of ancient
industry, etc.
Tarnishing
 Definition: ______________________________________________________________________
•
silver tends to turn _____________________ over time
•
copper tends to turn _________________
Silver Tarnish

when a metal tarnishes, a __________________________________ is occurs between the ____________
and molecules in the _______________________

balance the following reaction between pure silver, hydrogen sulfide and oxygen in the air
•
O
__Ag(s) + __H2S(g) + __O2(g)  __Ag2S(s) + __ H2O(l)

complete the Lewis dot diagram for the reaction:

Note: the number of molecules drawn corresponded to the coefficients of the balanced equation.
•
__Ag(s) + __H2S(g) + __O2(g)  __Ag2S(s) + __ H2O(l)
•
when an equation is balanced, you can use the ___________________________ to compare the
________________of _______________________________________________________
Mole Ratio
 Definition: ___________________________________________________________________

This can be used to solve for the actual quantity of the substance in moles using the formula:
n required
n given

=
coefficient required
coefficient given
Since you will always need to solve for “n

required
nrequired = ngiven x coefficient required *
coefficient given
” the rearranged formula is:
OR
nR = nG x CoR
CoG
* Where “given” is the value that is provided for you in the question
and “required” is the value that you need to figure out.

a ratio does not tell you the exact amounts, but rather the
_________________________________

the ratio/ proportion is used to calculate ___________________________
_________________________________
•
•
O
Ex. a mole ratio for hydrogen to oxygen (above) is 2:1; this means TWO moles of hydrogen for
every ONE mole of oxygen are used in the reaction.
If 100 moles of hydrogen was required how much oxygen would you need?
o 50 moles…there is always HALF (2:1) as much oxygen as hydrogen
Steps to solving a mole ratios problem:
1)
write the balanced chemical equation for the reaction
___Fe+ ___ CuCl2 --> ___ FeCl3 + ___ Cu
2) identify the substance that is “given” (value provided in the question), and the substance that is “required”
(the value that you need to find) and write the numbers right under the required substance
___Fe+ ___ CuCl2 --> ___ FeCl3 + ___ Cu
3) use the mole ratio formula: by filling in the coefficients.
___Fe+ ___ CuCl2 --> ___ FeCl3 + ___ Cu
nR = nG x CoR
nR = _________ mol x _____
CoG
4) do it!! multiply the number of moles of “given” by the mole ratio to find the number of moles of the
“required”
nR = nG x CoR
CoG
O
nR = ________ mol x ____
nR = ________ = _______ mol of Cu
Practice Problem #1:
Determine the amount of silver required to make 0.876 mol of silver sulfide, based on the reaction given
above.
1)
write the balanced chemical equation for the reaction
2) Over the equation, write the “G’s” and “R’s” to remind yourself which values/ coefficients go where…fill them in!
3 & 4) use the mole ratio formula, fill in the coefficients & values, and do the math!
O
Practice Problem #2:
How many moles of oxygen are required to burn 5.0mol of propane (C3H8(g))?
Assignment:
O Practice problems (page 63)
O Q’s 4-6
O 2.1 Summary (page 68)
O Q’s 2 (b), 3 & 5 pg 68
Name: _______________________________________
Purpose
You will collect data for the following chemical reaction:
2 NaOH
(aq)
+ CaCl2(aq) → 2 NaCl(aq) + Ca(OH)2 (s)
The data you collect will allow you to compare the theoretical number of moles of calcium hydroxide
produced to the actual number of moles produced.
Materials









1.50 g of sodium hydroxide, NaOH(s)
2.10 g of calcium chloride, CaCl2(s)
distilled water
2, 100-mL beakers
filter paper
funnel
ring stand
drying oven
analytical balance
Pre-Lab Assignment
1. Use the periodic table to determine the molar mass of sodium hydroxide, calcium chloride, and calcium hydroxide.
(3 marks)
Chemical Compound/
sodium hydroxide
calcium chloride
calcium hydroxide
Formula
(NaOH)
( _________)
( _________)
Molar Mass
2. Using the masses given in the materials list, calculate the number of moles of sodium hydroxide and calcium
chloride that will be used in this experiment. (4 marks)
mass sodium hydroxide
mass calcium chloride
3. Use the mole ratio of calcium hydroxide to sodium hydroxide to predict the theoretical number of moles of calcium
hydroxide that should be produced. (3 marks)
4. Use the mole ratio of calcium hydroxide to calcium chloride to predict the theoretical number of moles of calcium
hydroxide that should be produced. (3 marks)
Procedure
 Refer to pages 66-67 in your textbook for Procedure.
 Calculate the mass of calcium hydroxide produced by this reaction. Record this value in your observations
table below.
 Determine the number of moles of calcium hydroxide that were produced in this investigation. Show
your work. Record this value in your observations table.
Observations
Predicted (theoretical) values

Moles of calcium hydroxide produced:
Measured (experimental) values

Mass of filter paper AND calcium hydroxide:

Mass of filter paper:
Chemical
Molar Mass (g/mol)
Mass (g)
# of moles (mol)
sodium hydroxide
calcium chloride
calcium hydroxide
Post-lab Evaluation
1. Compare your experimental value for the number of moles of calcium hydroxide to the theoretical value you
calculated in the pre-lab analysis. (1 mark)
2. What difficulties did you encounter that may have affected the accuracy of your results? (2 marks)
3. Describe some steps you could take to minimize difficulties and make this investigation more accurate. (2 marks)
2.2 - The Gain and Loss of Electrons
O
metals are an important resource, but pure metals are rarely found in nature.
 the term ore refers to a rock containing enough useful metal to be mined
Formation of ionic compound
 a metal is made of cations surrounded by _____________________________________________

some of these electrons will be lost to other atoms in the environment
o
result: the number of free-floating electrons is no longer equal to the number of positive charges
o
metals that ______________________________ become _______________________________
Calcium atom
20 p+
20 eNet charge = 0
O
Calcium ion
20 p+
18 eNet charge = 2+
the atoms that picked up the extra electrons become ________________________________________
 these are called _______________________
 result: the number of free-floating electrons is no longer equal to the number of positive charges
Phosphorus atom
15 p+
15 eNet charge = 0
Phosphorus ion
15 p+
18 eNet charge = 3 –
O
positively-charged cations are attracted to the negatively-charged anions.
O
the ________________________________ of valence electrons results in an ___________________
Oxidation: The loss of electrons
O
when an atom loses an electron it is _______________________
 oxidation is a chemical process which a substance loses electrons
O
two types of oxidation reactions
 metal atom (neutral)  metal ion + electrons
o e.g. ___________________________________
 non-metal ion (charged)  non-metal atom + electrons
* Notice how the electrons are always
on the PRODUCT side of the reaction
o e.g. ___________________________________
Reduction: The gain of electrons
O
O
when an atom gains an electron it is _________________________
two types of reduction reactions
 metal ion (charged) + electrons  metal atom
o e.g. ____________________________________
 non-metal atom (neutral)  non-metal ion + electrons
o e.g. _____________________________________
* Notice how the electrons are always on
the REACTANT side of the reaction
L.E.O the lion says G.E.R
L=
G=
E=
E=
O=
R=
REDOX Reactions
O
following the Law of Conservation of Matter; ____________________________________________
______________________________________
 The electrons that are gained by one element must come from the element that loses them.
O
in a ________________________________________, an element reacts with a compound to produce a new element
and a new compound
O that means there are three elements involved altogether:
 One element will be _______________________ (and give up/lose electrons)
 One element will be _______________________ (and gain the excess electrons)
 One element will be the “________________________” (it will remain the same, as an ion, on both sides of
the reactions
Example: Single Replacement Reactions
O in order to get a valuable metal our of an ionic compound, a less valuable metal can be used to take its place in the
compound.
 most silver is found as the compound silver sulfate. The pure silver can be collected by reacting the silver
sulfate with zinc metal.
→ Identify the substance being:
o oxidized (losing electrons)
o reduced (gaining electrons)
o spectating (staying the same)
step 1: write out the reaction
Ag2SO4(s) + Zn(s)  ZnSO4(s) + 2 Ag(s)
step 2: identify each atom, and classify them as either an element or an ion on BOTH sides of the equation
Ag2SO4(s) + Zn(s)  ZnSO4(s) + 2 Ag(s)
2 Ag+(aq)  2 Ag(s)
Zn(s)  Zn2+(aq)
SO42-(aq)  SO42-(aq)
step 3: determine whether each reactant had to gain or lose electrons to become the product
Ag2SO4(s) + Zn(s)  ZnSO4(s) + 2 Ag(s)
2Ag+(aq) __________  2Ag(s)
the silver had to gain electrons = _________________
Zn(s)  Zn2+(aq) __________
the zinc loses electrons = ____________________
SO42-(aq)  SO42-(aq)
the sulfate is unaffected = ___________________________________
Assignment:
O Practice problems (page 72)
Q 15
O Practice problems (page 74)
Q 18
O Practice problems (page 75)
Q 20& 21
O 2.2 Summary (page 75)
Q’s 2 & 4
2.3 - The Gain and Loss of Electrons
Stability vs. Reactivity
Some metals are very stable – they can be found in pure form, and don’t often form compounds.
O

e.g. ________________________
Metals that are reactive, tend to corrode easily.
O

e.g. ________________________
corrosion is the oxidation of a metal
O

e.g. _________________________________________________________
Simulation
Four different metals are immersed into four different ionic solutions, and the results recorded.
 If nothing occurs, then “no reaction” will be noted.
 If a change occurs, then “reaction” will be noted.
 The results should be as follows:
O
Results
O
rank the ions in order from most to least reactive

O
rank the metal atoms in order from most to least reactive

O
______  ______  ______  ______
______  ______  ______ ______
what connection do you see between the reactivity of an ion and its stability as an atom?
 _______________________________________________________________________________________
The activity series
O
O
A list that organizes metal atoms from most stable to least stable
Simultaneously organizes metal ions from most reactive to least
reactive

O
O
see textbook page 80 or page 4 of your data booklet
when read left to right you get a ___________________________

Example:

_____________________________________
If read right to left you get an ______________________________
(flip the arrow around in your head)

O
Example:
 _____________________________________
an activity series allows you to:
1. compare the relative reactivity of metal ions

Use LEFT SIDE; _________________________________________________= _____________________
2. compare the relative reactivity of metal atoms
3. use RIGHT SIDE, _________________________________________________= _______________________
determine if a reaction will occur spontaneously

a spontaneous reaction is one that will ________________________ without the addition of energy

to determine if a reaction is spontaneous, locate the two half-reactions on the table

if the reduction reaction (LR) is located above the oxidation reaction (RL) _________________
____________________________________

a non-spontaneous reaction will have the reduction reaction located ___________________
_____________________________________
Activity Series-Example
O
A piece of solid magnesium is placed in a solution containing silver ions.
Step 1: identify reactants

_________________________________________________
Step 2: identify half-reactions

reduction reaction (LR) = ________________________

oxidation reaction (RL) = ________________________
Step 3: determine spontaneity…

If the reduction reaction (LR) is above the oxidation
reaction (RL) = ________________________________

reduction reaction (LR) below the oxidation reaction (RL) =
___________________________________________

_________________________________
oxidation reaction
Practice Problem #1
A piece of zinc is placed in a solution containing Cu 2+ ions
a. write the oxidation and reduction half reactions.
b/c the silver reduction rxn is above the magnesium
Practice Problem #2
A piece of gold jewelry is placed in a solution containing
H+ ions
a. write the oxidation and reduction half reactions.
b. determine if the reaction will occur spontaneously
b. determine if the reaction will occur spontaneously
c. explain how you knew it was spontaneous or not.
c. explain how you knew it was spontaneous or not.
Oxidizing and Reducing Agents
O
In keeping with the Law of Conservation, one substance cannot gain electrons
(be reduced) without another substance providing the electrons (being
oxidized).
O
A _____________________________________ must stimulate the loss of
electrons, in order for them to be available for the substance being reduced.
O
the reducing agent is the entity that CAUSES _____________________________
_________________________

O
the oxidizing agent is the entity that CAUSES ______________________________________________________

O
it is itself ___________________________________
it is itself ___________________________________
Consider the following analogy:
A travel agent does not travel themselves, but rather their actions allow someone else to travel.

in a similar way, the oxidizing agent is the one that enables another substance to be oxidized, and the
reducing agent enables the other substance to be reduced.
Assignment:
O Practice Problems (page 79)
 Q 24 & 25
O Practice Problems (page 82)
 Q 28 & 29
O Practice Problems (page 83)
 Q 30(a,c,e,g,i) & 31
O
2.3 Summary (page 85)
 Q’s 3 & 5
Science 20 – A2.1-2.3 – Redox and Activity Series Assignment
1. Complete the following table:
2. A cheap way to remove the tarnish off of silver jewelry or cutlery is to place the item in a dish of hot water
lined with aluminum foil. The aluminum reacts with the Ag2S(s) and removes the tarnish, according to the
following reaction:
3 Ag2S(s) + 2 Al(s) + 3 H2O(l)  6 Ag(s) + Al2O3(s) + 3 H2S(aq)
You have 4.29 x 10-3 mol of silver tarnish, Ag2S(s), on a spoon.
a. How many moles of water are required in the reaction that converts the tarnish back into silver?
b. How many moles of silver will be produced during the reaction?
c. How many moles of aluminium oxide will be produced during the reaction?
3. How much oxygen is required to completely burn 5.0 mol of methanol (CH3OH(l))?
4. A silver nitrate solution reacts with solid zinc to produce zinc nitrate solution and solid silver.
a. Write a balanced chemical reaction that describes this reaction.
b. Write the half reaction for each substance, and identify it as oxidation, reduction, or a spectator ion.
c. How many electrons in total were transferred?
5. When copper metal is placed into a solution of silver nitrate, silver metal and copper nitrate are produced.
Cu(s) + 2 AgNO3(aq)  2 Ag(s) + Cu(NO3)2(aq)
a) Identify the chemical substance that is gaining
electrons.
d) Identify the atom or ion that is oxidized.
b) Identify the chemical substance that is losing
electrons.
e) Identify the atom or ion that is reduced.
c) Identify the chemical substance that is spectator
ion.
f) Determine the number of electrons transferred in
the reaction.
g) If 11.0 mol of copper react with silver nitrate, how many moles of silver metal will form?
6. Explain the relationship between the reactivity of a metal atom and the reactivity of its metal ion.
7. Describe three observations that would lead you to conclude that a reaction is spontaneous.
8. A student performed an experiment to determine if reactions between certain metals and metal ions
occurred spontaneously.
a. Use the activity series to complete the following table. Use an X to indicate no reaction, and a  to
indicate a spontaneous reaction. Remember, the reaction will occur spontaneously if the reduction
half-reaction (metal ion  metal atom) is listed above the oxidation half-reaction (metal ion 
metal atom)
Mg(s)
Cu(s)
Al(s)
Ni(s)
2+
Mg (s)
X
2+
Cu (s)
X
Al3+(s)
X
2+
Ni (s)
X
b. List the metals in order from most reactive to most stable.
c. List the metal ions in order from most reactive to most stable.
Bonus: You have been given a contract by an employer to design an inexpensive metal container that
will be used to store large amounts of water contaminated with lead(II) ions, Pb2+(aq). The
solution will need to be stored for a long period of time. Describe suitable materials required to
build this kind of container.
2.4 – Voltaic Cells
O
O
the focus on metals so far been what happening on the surface of the metal

tarnishing/ rusting, (aka color change), precipitate formation or bubbles/ gas
formation
The rest of the chapter focuses on WHY this occurs.

a focus on the movement of electrons between the two metals
Voltaic cells
O
O
though commonly a voltaic cell is referred to as a “battery”, technically cells are only
referred to as a battery when _________________________________________
O when an electronic device is operating, voltaic cells provide a continuous flow (current) of electrons, which
is converted into current to power the device
when an electronic device is operating, voltaic cells provide a continuous flow (current) of electrons, which is
converted into current to power the device.
 the voltaic cell that you know looks like this:
O this is version of the voltaic cell we will make in the lab.
Structure of a voltaic cell:
O an _________________________ is a solid piece of metal that is suspended in a solution (of the ______________
__________________________________as the electrode) and connected to an external circuit.
 the electrode zinc, is immersed into an electrolyte solution, where the zinc electrode acquires an excess of
electrons, becoming negatively charged
 the other electrode is usually composed of a different material (copper) and will become positively charged
O once a circuit is closed between the two electrodes, the electrons will repel from the negative zinc electrode, pass
through the circuit and flow through to the positive electrode.
 the reaction will continue until the negative electrode can no longer be supply electrons.
O a __________________________________ is a glass U-shaped tube that is filled with an ionic solution

this is to allow for ___________________________________ from one solution to the other
How the cell works:
O
because it is the more reactive of the two metals ________________________________________________
_______________________, (lose electrons)
O
these electrons will travel from the electrode, through a metal wire, and then into an electronic device
 the device; a ____________________________________, measures the quantity of electrons passing through
it (= amount of electricity)
O
the electrons will pass through the device, back through another wire, into the copper electrode

these electrons will be attracted to ____________________________________________________________
and they will be reduced.
O
over time, the zinc electrode shrinks in size (as Zn  Zn2+) and the copper electrode grows (Cu2+  Cu)
O
if the two solutions were not connected, _____________________________________________________________
and the cell would stop working
 the solution in the salt bridge allows a continuous flow of electrons back into the zinc solution
Analyzing a voltaic cell
Step #1: identify the electrode where oxidation occurs
O
locate the two metals on the activity series (_____________________)
 the metal closer to the BOTTOM will be OXIDIZED = reducing
agent

the electrode that is _____________________ is called the
___________________

the other electrode is ___________________________, and is called
the ___________________________
Step #2: describe the oxidation process in the anode
O
write the oxidation half-reaction

Eg. Pb(s)  Pb2+(aq) +2e-
O
electrons leave the anode and travel to the external circuit running the electronic
device
 the voltmeter measures the quantity of electrons (amount of electricity) being
produced
O
because the anode is the electrode where the ________________________________,
it is considered the ________________________________________
Step #3: describe the reduction process in the anode
O
the electrons travel through the voltmeter and into the cathode
O
the electrons are attracted to the ___________________________________________________ in the cathode
solution
the cathode ions will unite with the electrons and form a solid metal, which is deposited on the electrode
O

Eg. Ag+ (aq) + e-  Ag (s)
Step #4: describe how the salt bridge completes the circuit
O
all electrical circuits require a complete circuit in order to function.
O
the salt bridge ________________________________________________________________________________
to replenish the electrons on the anode side

the salt bridge contains a third ionic solution

the _____________________________ from the salt bridge solution will be attracted to the
_________________________________, while the
__________________________________ from the salt bridge solution
will
migrate toward the _________________________________.
Voltaic Cell- Example
O
in this voltaic cell:
 zinc is the _____________ – it is oxidized

copper is the __________ – it is reduced

the solution in the salt bridge is _______(aq)

chloride ions are a spectator ion – their job is to replenish the electron supply at the anode
Cell Notation
O
voltaic cells can also be represented using short hand cell notation
Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s)
anode
salt bridge
 ___________________
O
cathode
 ___________________
the anode is listed on the left, the cathode on the right (think alphabetical order)

the vertical line | represents a boundary between a metal and its solution

the double line || represents the salt bridge
Practice Problem #1:
a) Draw a voltaic cell using the following supplies:
→
→
→
→
→
two beakers
U-tube & cotton balls
wire & voltmeter
tin and magnesium strips
solutions of SnSO4(aq), MgSO4(aq), and NaNO3(aq)
b) Label the direction of e- flow, the anode, cathode, OA, RA, - and + electrodes, voltmeter and salt bridge
c) Write the short hand cell notation
Assignment:
O
O
O
O
Practice problem (page 87)

34
Practice problems (page 91)

37 & 39
Practice problem (page 92)

40
2.4 Summary 9page 94)
 Q’s 2, 3 & 6 pg 94
Name: _____________________________
Purpose
Design two voltaic cells that create a maximum and minimum output on a voltmeter.
Materials
→
→
→
→
→
→
→
2 beakers (250 or 300mL)
glass U-shaped tube
cotton balls
wire (with clamps)
voltmeter
iron, copper, magnesium and zinc metal strips
ionic solutions: Fe(NO3)2(aq), Cu(NO3)2(aq), Mg(NO3)2(aq), Zn(NO3)2(aq), K2SO4(aq)
Pre-Lab Assignment
1.
Using the activity series, describe how you can predict when a voltaic cell will run spontaneously?
2. How do the positions of the two metals on the activity series affect the voltage produced?
3. Based on the list of metals and solutions listed above, predict which combination will make the cell with the
largest electrical output on a voltmeter and which would create the minimum output?
Maximum
Minimum
anode -
anode -
cathode -
cathode -
4. Create a labeled diagram for each of the two cells you intend to build. Be sure to label the anode, cathode, all
three solutions and identify the direction of the electron flow.
5. Using the information provided in the notes and page 88 in your textbook to write a detailed, yet succinct,
procedure for how to assemble a voltaic cell.
Procedure criteria → must be on a separate sheet of paper
→ must numbered (step-by-step)
→ must NOT be plagiarized! Make sure the info. from the notes and page 88 is rephrased in your own words!
→ must be clear, concise and easy to follow
WARNING; you will be swapping your procedure with another group on the day of the lab, so it must be
descriptive and detailed enough that another person will be able to follow your instructions without verbal
guidance. You will be marked on the success of your procedure NOT how well you can assemble your own
voltmeter, so you need to be accountable to your peers. The following rubric will be used to assess your
procedure:
Word Choice:
Organization:
5- Strongly Evident
Precise language; uses scientific terms
and phrases accurately and
appropriately.
The order, presentation, and
structure of the procedure guide the
reader purposefully through the
text.
3-Evident
The language communicates in
a routine, workable manner;
gets the job done.
The order allows the reader to
move through the text without
undue confusion. Reader must
assume details and “fill-in-theblanks”
1- Not Evident
Struggles with a limited vocabulary (may use
terms/ phrases incorrectly) – procedure is not
useful for the reader.
Steps or details seem loosely strung together;
difficult to follow OR reader could not use
procedure to assemble cell.
Procedure
1. Pair-up with another group.
2. Swap procedures. Use the OTHER GROUPS procedure to assemble a voltmeter.
a. “Group one” will assemble a voltaic cell using materials to produce the MAXIMUM voltage.
b. “Group two” will assemble a voltaic cell using materials to produce the MINIMUM voltage.
3. Once the cell is assembled and running, record the reading of the voltmeter for BOTH cells in the observations
section below.
4. Carefully de-assemble your voltmeter: dry electrodes and ensure all solutions are placed in the appropriate wastecontainers.
Observations
Maximum reading on voltmeter:
Minimum reading on voltmeter:
Post-lab Evaluation
1.
Describe two improvements you could make to the voltaic cell to produce an even higher voltage.
2. After having to both write and follow a procedure for how to make a voltaic cell;
a. Evaluate the procedure YOU WROTE: identify what you feel you did well, and what you think you could
have improved on.
b. Evaluate the procedure had to follow: identify what you feel they did well, and what they could have
improved on.
2.5 - Electrolytic cells
Electrolytic vs. Voltaic
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an electrolytic cell is a system where ____________________________________________________________________
is forced to occur

a reaction that is non-spontaneous will only occur if energy is added
Voltaic
Electrolytic
spontaneous?
requires energy?
produces voltage?
use
change in energy

in an electrolytic cell, energy is added in the form of electricity
Electroplating
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metals, like gold and silver, that are the most stable and corrosion-resistant are also the most
expensive

to manufacture a metal object that is resistant to corrosion it would NOT be cost-effective
to make the whole thing out of gold

instead, _____________________________________________ is applied to the surface of a
more affordable metal
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this turns the metal ions into metal atoms, which will accumulate on the surface of the metal
object.
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an external energy source (a battery) supplies energy forcing ___________________________
________________________

the negatively charged electrons will _________________________________________
from the solution, and turn them back into metal atoms, which will accumulate on the
surface of the object to be plated.
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electroplating is a good way to protect metals that are easily oxidized, like iron

metals that work as good electroplaters (coatings) are ______________________________
________________________________________
Electrolytic cells
Step #1:
electrons from the plating (the expensive) metal cathode are attracted to the
________________________________
by removing electrons from the metal atoms, ions are formed and
__________________________________________
Step #2:
once removed from the metal, the free electrons flow ______________________________________.
Step #3:
electrons are forced _____________________________________________ and _______________
______________________ of the object to be plated
Step #4:
positive _________________________________ are ____________________________________________________
in the object to be plated
the Au+(aq)ions ____________________________________, and ____________________________________________
coating the object.
Gold jewelry
two types of gold jewelry exist - that which is made out of solid gold, and that which is gold plated
 karats - pure gold is 24K
 gold is a soft metal, so it is often combined with other metals like brass (copper and zinc) and
nickel to make it more durable
 the number of karats in the gold refers to how many 1/24th of gold it contains
 by law, every piece of gold jewelry must be stamped with the karat mark
 if you have a piece of gold plated jewelry, care must be taken to avoid any deep scratches
 deep scratches will __________________________________________________
Other Uses for Electrolytic Cells
Refining metals
 a sample of impure metal (anode), pure metal (cathode)
 ions of the pure metal will travel from the anode to the cathode to build up the atoms of pure metal
Electrolysis
 decomposition of a compound by means of an electric current
 e.g. electrolysis of water makes it decompose into O 2 and H2
Producing non-metals
 non-metals, especially the halogens, are difficult to obtain in pure form because they are so reactive
 non-metal atoms will accumulate around the anode of an electrolytic cell
Recharging voltaic cells
 when you use a battery recharger, you are using an electrolytic cell to reverse the process that occurs
normally in the voltaic cell
 you are literally re-charging the voltaic cell with a new supply of electrons.
Assignment:
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Complete the Voltaic & Electrolytic cells
Worksheet
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File - Mr. Downing Science 20