Bellringer 9/20
1. How many protons does mercury have?
Electrons? Neutrons?
2. Which subatomic particle determines the
kind of element?
3. Which subatomic particles determine a
element’s chemical properties?
4. What are valence electrons?
Bellringer 9/21
1. What is a saturated solution?
2. How are unsaturated solutions different from
supersaturated solutions?
3. What are 3 ways to speed up the rate of
dissolving a solute in a solvent?
Core Concepts 1&2
Solutions
• A homogeneous mixture of two or more
substances.
• Can be separated by physical means.
• Can occur in the solid, liquid, or gas phase.
• Solute – the part of the solution that is dissolved
and usually present in the lesser amount. (saltsolute, water-solvent)
• Solvent – the part of the solution doing the
dissolving and usually present in the greater
amount.
• Solutions are classified as unsaturated,
saturated, and supersaturated.
• A saturate solution has the maximum
dissolved solute for the amount of solvent
used at a specific temperature and pressure.
• Electrolyte – an aqueous solution that
conducts electricity. Pure water does not
conduct electricity well.
• Aqueous solution – solution where water is
the solvent. Water is a polar solvent. That
means it is a molecule which has a (+) and (-)
side.
• Like dissolves like – This means that a solute
will dissolve best in a solvent that has the
same or similar polarity.
• Solubility and Temperature Gizmo |
ExploreLearning
Factors that affect dissolving rate
1. Surface area – greater surface area dissolves
faster.
2. Higher temperatures dissolve faster because
the particles move faster.
3. Stirring dissolve faster because the particles
spread out faster in the solvent.
Pg 238 1 - 5
Bellringer 9/22
1. Why does stirring increase the dissolving rate
of a solute in a solvent?
2. Why does heating increase the dissolving
rate of a solute in a solvent?
3. Why does increasing surface area of a solute
increase the dissolving rate? List one way to
increase the surface area of a solute.
Solutions
• Concentration – the quantity of solute
dissolved in a certain amount of solvent.
Concentrated has a large amount of solute –
diluted has a small amount.
• Concentration is expressed as molarity or
moles per liter of solution.
Bellringer 9/23
A solution of sodium sulfide (Na2S) has a solubility
of 26.3g/100g of H2O at 200C.
1. What is this solution know as?
2. About how much sodium sulfide would be
needed for the solution to be unsaturated?
3. About how much would be need to be
supersaturated?
4. If the temperature was raised to 600C, would
you expect more or less than 26.3g to dissolve in
the 100g of water?
Ionic and Covalent Bonding
• Bonded atoms form many kinds of substance.
Example: sodium (Na) and chlorine (Cl) bond
to form NaCl (table salt).
• Atoms bond when their valence electrons
interact.
• Atoms join to form bonds so that each atom
has a stable electron configuration like those
of the Noble Gases.
Ionic Bonding
• Formed between oppositely charged ions.
• An ion is a charged atom with either more or
less electrons than protons.
• Formed by the transfer of electrons. Example:
sodium (Na) transfers its one valence electron
to chlorine (Cl) so that Na now has 8 outer
level electrons and Cl with 7 before the
transfer, has 8 outer electrons. Na is now
positive (+) or cation, and Cl negative (-) anion.
• Calcium can combine with chlorine to form
calcium chloride. Calcium (Ca+2) has 2 valence
electrons and so it takes 2 chlorine ions (Cl-) to
balance with it. Cl- + Ca+2 + Cl- The chemical
formula is CaCl2.
• Electron dot diagrams.
• Electron Dot Diagram – YouTube
Draw electron dot diagrams for the following
elements: Na, Ca, O, F, Ne, Kr, Al, and N. Will they
be cations or anions?
Writing formulas for Ionic Compounds
What is the chemical formula for aluminum
fluoride?
Look up symbol for aluminum ion:
Al+3
Look up symbol for fluoride ion:
FAl+3 FIt will take 3(-) to balance with +3 or 3F to balance
with 1 Al.
AlF3
Write the chemical formula for the
following:
1. Iron (II) Iodide (hint: the roman numeral
indicates the cation’s charge)
2. Potassium Nitrate
3. Aluminum Chloride
4. Magnesium Oxide
5. Lithium Sulfide
6. Titanium (IV) oxide
Dot Diagrams of Selected Elements
Formulas Lesson 3: Transition Metals Part 1 – YouTube
Formulas Lesson 4: Transition Metals Part 2 - YouTube
Polyatomic ions
• Ions made up of 2 or more atoms.
• They act the same as elemental ions.
Example: (NH4)+ is the ammonium ion. (NO3)- is
the nitrate ion. Since one is + and the other is
(-) then ammonium nitrate’s chemical formula
is NH4NO3
• Anions end in –ite or –ate for most of them.
.Polyatomic Ion Charge = +1
ammonium - NH4+
Polyatomic Ion Charge = -2
carbonate - CO32chromate - CrO42dichromate - Cr2O72hydrogen phosphate - HPO42peroxide - O22sulfate - SO42sulfite - SO32thiosulfate - S2O32-
Polyatomic Ion Charge = -1
acetate - C2H3O2bicarbonate (or hydrogen carbonate) - HCO3bisulfate (or hydrogen sulfate) - HSO4chlorate - ClO3chlorite - ClO2cyanate - OCNcyanide - CNPolyatomic Ion Charge = -3
dihydrogen phosphate - H2PO4borate - BO33hydroxide - OH
phosphate - PO43nitrate - NO3
nitrite - NO2perchlorate - ClO4permanganate - MnO4thiocyanate - SCN-
Using the chart to write chemical
formulas.
Example: What is the chemical formula for
sodium hydroxide?
Na+ is paired with (OH)-. Since they both have a
single charge then combine them and drop
the signs.
NaOH
Example: ammonium sulfate?
Ammonium is (NH4)+ and sulfate is (SO4)-2. It
takes 2 (NH4)+ to pair with one (SO4)-2.
The formula is (NH4)2SO4. Notice that there are
2N and 2H4 so counting atoms there are
(NH4)2SO4
8 – hydrogen (H) atoms
2 – nitrogen (N) atoms
1 – sulfur (S) atom
4 – oxygen (O) atoms
Naming and Formulas of SOME Polyatomic Ions:
Chemistry Lesson - YouTube
Write the chemical formulas for the following:
Use the chart on page 158 and the periodic table.
1.
2.
3.
4.
5.
6.
7.
8.
hydrogen phosphate
hydrogen carbonate
Potassium hydroxide
Calcium chlorate
Calcium carbonate
Sodium phosphate
Sodium cyanide
Aluminum sulfate
Chemical Reactions
• Chemical reactions change substances.
• Reactants – the substances that are used in
the chemical reactions.
• Products – the new substances formed from
the reactants in the chemical reactions.
• Endothermic reaction – reactions that absorb
energy during the reaction. (Cold packs)
• Exothermic reaction – reaction that releases
energy during the reaction. (heat packs)
Classifying Reactions
• Synthesis reactions – reactions where two or
more substances combine to form a new
compound. 2Na + Cl2  2NaCl (notice that 2
Na on both sides of arrow and 2 Cl also)
• Decomposition reaction – a reaction where a
compound breaks apart into 2 or more
substances. 2H20  2H2 + 02
Chemical Reactions
• Combustion reaction – The oxidation reaction
of an organic compound in which heat is
released.
2CH4 + 4O2  2CO2 + 4H2O
Methane gas reacting with oxygen producing
carbon dioxide and water.
Chemical reactions
• Single-displacement reaction – A reaction in
which one element or radical takes the place
of another element or radical in a compound.
3CuCl2 + 2Al  2AlCl3 + 3Cu
Copper is replaced with aluminum
A more reactive element takes the place of a
less reactive one.
A radical is an organic group that has one or
more electrons available for bonding.
Chemical reactions
• Double-displacement reactions – a reaction in
which a gas, a solid precipitate, or a molecular
compound forms from an apparent exchange
of atoms or ions between two compounds.
Pb(NO3)2 + K2CrO4  PbCrO4 + 2KNO3
Lead nitrate reacting with potassium chromate
to produce lead chromate and potassium
nitrate.
Chemical Reactions
• Oxidation-reduction reaction – any chemical
change in which one species is oxidized (loses
electrons) and another species in reduced (gains
electrons). Referred to as redox reaction.
Respiration (breathing) is a redox reaction. Oxygen
gas reacts with carbon compounds to form
carbon dioxide. Carbon atoms in CO2 are oxidized
(lose electrons) and Oxygen atoms are reduced
(gain electrons).
Elements_of_Chemistry__Compounds_and_Reactio
ns.asf
Classify the following reactions
1. La2O3 + H2O  La(OH)3
2. NH4NO3  N2O + H2O
3. C3H8 + O2  CO2 + H2O
4. Mg + HCl  MgCl2 + H2
5. Mg(OH)2 + HCl  MgCl2 + H2O
Put yes behind those equations that are
balanced.
Bell Ringer
Identify the following reactions
1. CaSO4 + Mg(OH)2 --> Ca(OH)2 + MgSO4
2.
3.
Balancing Chemical Equations
Mg + HCl  MgCl2 + H2
Is this equation balanced?
No since there are 2 Hs and 2 Cls on the right
side and only one each on the left side.
Suppose we put a 2 in front of HCl.
Mg + 2HCl  MgCl2 + H2
Is it now balanced?
Balance these equations
1) ____ N2 + ____ H2  ____ NH3
2) ____ KClO3  ____ KCl + ____ O2
3) ____ NaCl + ____ F2  ____ NaF + ____ Cl2
4) ____ H2 + ____ O2  ____ H2O
5) ____ Pb(OH)2 + ____ HCl  ____ H2O + ____ PbCl2
6) ____ AlBr3 + ____ K2SO4  ____ KBr + ____ Al2(SO4)3
7) ____ CH4 + ____ O2  ____ CO2 + ____ H2O
8) ____ C3H8 + ____ O2  ____ CO2 + ____ H2O
Check your work
1) 1 N2 + 3 H2  2 NH3
2) 2 KClO3  2 KCl + 3 O2
3) 2 NaCl + 1 F2  2 NaF + 1 Cl2
4) 2 H2 + 1 O2  2 H2O
5) 1 Pb(OH)2 + 2 HCl  2 H2O + 1 PbCl2
6) 2 AlBr3 + 3 K2SO4  6 KBr + 1 Al2(SO4)3
7) 1 CH4 + 2 O2  1 CO2 + 2 H2O
8) 1 C3H8 + 5 O2  3 CO2 + 4 H2O