Tuesday, October 23rd
 Review
 Quiz
 Finish Chapter 6,
 Begin Chapter 7
 Group Assignment
1
Review
2
Naming
Ionic Compounds - When a metal is bonded to a nonmetal:
1. Name the metal.
2. Name the anion, use the first syllable and add –ide, at the
end.
3. IF the metal is a transition metal (not an alkali or alkaline
earth metal) then a roman numeral (I, II, III, IV, etc.) must be
used after the metal name to give the charge state.
Covalent Compounds – When a nonmetal is bonded to a nonmetal:
1. Name the first nonmetal, then the second nonmetal, use the
first syllable and add an –ide, at the end.
2. Identify the number of each atom type (using the subscripts)
then insert the correct prefixes (mono, di, tri, tetra, etc.) before
the atomic name. Remember that a mono used on the first
element is left off.
3
Balancing Ionic Formula
1. Find the charge on each ion.
2. Determine the ratio of the charges needed to get an overall
zero charge.
3. Use this ratio as the subscripts (N2) in the balance
formula.
4. If there is a polyatomic ion being used and there are more
than one, then parentheses are needed around the ion,
whether it is the cation or anion, example: Ba(OH)2.
4
Drawing Electron Dot Formulas
1. Draw the central atom with the other atoms around it (don’t include bonds
yet).
2. Count the total number of valence electrons for the compound by first
multiplying the subscript for each atom in the compound by the number of
valence electrons each atom has and then adding all the valence electrons
together.
3. Place one bond between the central atom and each of the other atoms.
4. Count the number of valence electrons used in the bonds (don’t forget the 2
e- per bond)
5. Subtract the total number of valence electrons from the number used in
bonding (so answer from #2 – answer from #4). This tells you how many
electrons you have left.
6. Place the remaining electrons giving all atoms an octet (start with the non
central atoms first and then move to the central atom). (NOTE: Hydrogen
and Helium have an octet when they have 2 electrons.)
7. When you have used all of the electrons available, check all of the atoms to
see if they have an octet.
8. If the central atom is short of an octet, then start making double/triple bonds.
In order to do this, erase a lone-pair of electrons from one of the non central
atoms and put it into a second or third bond between that atom and the
central atom. Repeat this until all of the atoms have octets.
5
Summary Reaction Types
Balancing Equations
1. Write the chemical equation using the correct molecular
formulas.
2. Make a list of all of the atoms on the reactants and products
(if a polyatomic ion is listed on the reactants and products
than it can be left intact and dealt with as one species).
3. If the values aren’t even, begin to balance the equation by
using only Coefficients in front of the molecular formulas to
change the number of molecular units. (Do not change any
subscripts)
4. When balancing, start with the metal atoms or carbon (in the
case of a combustion reaction).
5. Balance single elements in the equation last.
7
Practice
Balance the equations for the combustion of propane
(C3H8) and butane (C4H10).
8
Avogadro’s Number as an
Equality
Avogadro’s number (6.02 x 1023) can be written as an
equality and two conversion factors.
Equality:
Conversion Factors:
Subscripts State Atoms and Moles
Molar Mass
Molar mass is
 the mass of one mole
of a substance.
 the number of grams
that equals the atomic
mass of that element.
Molar mass is rounded
to the tenths (0.1 g)
place for use in this
text.
Learning Check
Determine the molar mass of K3PO4 to 0.1 g.
Solution
Determine the molar mass of K3PO4 to 0.1 g.
Quiz!!!!
14
Continuing on
in Chapter 6
15
Chemistry and Cooking
 Bisquick
2 Cups Mix
2 Eggs
1 Cup Milk
8 Pancakes
16
Mole–Mole Factors from
Chemical Equations
A mole–mole factor is a ratio of the moles (from the
coefficients) for any two substances in an equation.
Learning Check
Consider the following equation.
1. A mole–mole factor for H2 and N2 is
A.
B.
C.
2. A mole–mole factor for NH3 and H2 is
A.
B.
C.
Guide to Calculating Quantities in
a Chemical Reaction
Calculating Quantities in a
Chemical Reaction
How many moles of CO2 can be produced when
2.25 moles of C3H8 react according to the following
balanced reaction?
Mass of Product from Mass of
Reactant, C2H2
Acetylene gas, C2H2, burns in oxygen emitting high
temperatures used for welding metals. How many
grams of CO2 can be produced when 54.6 g of C2H2
are burned?
Step 1 State the given and needed quantities.
Analyze the Problem.
Mass of Product from Mass of
Reactant, C2H2
Acetylene gas, C2H2, burns in oxygen emitting high
temperatures used for welding metals. How many
grams of CO2 can be produced when 54.6 g of C2H2
are burned?
Step 2 Write a plan to convert the given, to the
needed quantity (moles or grams).
grams molar moles mole-mole moles molar grams
C2H2 mass C2H2 factor
CO2 mass CO2
Mass of Product from Mass of
Reactant, C2H2
Acetylene gas, C2H2, burns in oxygen emitting high
temperatures used for welding metals. How many
grams of CO2 can be produced when 54.6 g of C2H2 are
burned?
Step 3 Use coefficients to write mole–mole factors;
write molar mass factors if needed.
Mass of Product from Mass of
Reactant, C2H2
How many grams of CO2 can be produced when 54.6 g
of C2H2 are burned?
Step 4 Set up the problem to give the needed
quantity (moles or grams).
Learning Check
Determine the mass (g) of NH3 that can form from
62.3 grams of N2 according to the following reaction.
Solution
Determine the mass (g) of NH3 that can form from
62.3 grams of N2 according to the following reaction.
Step 1 State the given and needed quantities.
Analyze the Problem.
Solution
Determine the mass (g) of NH3 that can form from
62.3 grams of N2 according to the following reaction.
Step 2 Write a plan to convert the given to the
needed quantity (moles or grams).
factor
grams molar
molar moles mole-mole
moles molar
molar grams
mass
N2 mass
mass
N2 mole-mole
factor
NH3 mass
NH3
Solution
Determine the mass (g) of NH3 that can form from
62.3 grams of N2 according to the following reaction.
Step 3 Use coefficients to write mole–mole
factors; write molar mass factors if needed.
Solution
Determine the mass (g) of NH3 that can form from
62.3 grams of N2 according to the following reaction.
Step 4 Set up the problem to give the needed
quantity (moles or grams).
Learning Check
How many grams of C2H2 are burned if the reaction
produces 75.0 g of CO2?
A. 88.6 g of C2H2
B. 44.3 g of C2H2
C. 22.2 g of C2H2
Theoretical, Actual, and Percent
Yield
 Theoretical yield is the maximum amount of
product, which is calculated using the balanced
equation.
 Actual yield is the amount of product obtained when
the reaction takes place.
 Percent yield is the ratio of actual yield to theoretical
yield.
Guide to Calculations for
Percent Yield
Calculating Percent Yield
On a space shuttle, LiOH is used to absorb exhaled
CO2 from breathing air to form LiHCO3. What is the
percent yield of the reaction if 50.0 g of LiOH gives
72.8 g of LiHCO3?
Calculating Percent Yield
On a space shuttle, LiOH is used to absorb exhaled CO2
from breathing air to form LiHCO3. What is the percent
yield of the reaction if 50.0 g of LiOH gives 72.8 g of
LiHCO3?
Step 1 State the given and needed quantities.
Analyze the Problem.
Calculating Percent Yield
What is the percent yield of the reaction if 50.0 g of LiOH
gives 72.8 g of LiHCO3?
Step 2 Write a plan to calculate the theoretical
yield and the percent yield.
Calculation of theoretical yield:
grams
LiOH
molar
mass
moles mole-mole
LiOH factor
moles molar
LiHCO3 mass
Calculation of percent yield:
grams
LiHCO3
Calculating Percent Yield
What is the percent yield of the reaction if 50.0 g of LiOH
gives 72.8 g of LiHCO3?
Step 3 Write the molar mass for the reactant and the
mole–mole factor from the balanced equation.
Calculating Percent Yield
What is the percent yield of the reaction if 50.0 g of LiOH
gives 72.8 g of LiHCO3?
Step 3 Write the molar mass for the reactant and the
mole–mole factor from the balanced equation.
Calculating Percent Yield
What is the percent yield of the reaction if 50.0 g of LiOH
gives 72.8 g of LiHCO3?
Step 4 Solve for the percent yield ratio by dividing the
actual yield (given) by the theoretical yield and
multiplying the result by 100%.
Calculation of theoretical yield:
Calculating Percent Yield
What is the percent yield of the reaction if 50.0 g of LiOH
gives 72.8 g of LiHCO3?
Step 4 Solve for the percent yield ratio by dividing the
actual yield (given) by the theoretical yield and
multiplying the result by 100%.
Calculation of percent yield:
Limiting Reactant
A limiting reactant in a chemical reaction is the
substance that is used up first and limits the amount of
product that can form. The other reactant, called the
excess reactant, is left over.
Example: Limiting Reactant
How many peanut butter sandwiches could be made
from 8 slices of bread and 1 jar of peanut butter?
With 8 slices of bread, only 4 sandwiches could be
made. The bread is the limiting item.
Example: Limiting Reactant
How many peanut butter sandwiches could be made
from 8 slices of bread and 1 tablespoon of peanut
butter?
With 1 tablespoon of peanut butter, only 1 sandwich
could be made. The peanut butter is the limiting item.
Calculating Moles of Product from
Limiting Reactant
Calculate the moles of product (CH3OH) that can form
given 3.00 moles of CO reacts with 5.00 moles of H2.
What is the limiting reactant?
a. What mole–mole equalities will be needed in the
. calculation?
b. What are the mole–mole factors from these
. equalities?
c. What is the number of moles of CH3OH from each
. reactant?
d. What is the limiting reactant for the reaction?
Calculating Moles of Product from
Limiting Reactant
Calculate the moles of product (CH3OH) that can form
given 3.00 moles of CO reacts with 5.00 moles of H2.
What is the limiting reactant?
a. What mole–mole equalities will be needed in the
calculation?
1 mole of CO = 1 mole of CH3OH
2 moles of H2 = 1 mole of CH3OH
Calculating Moles of Product from
Limiting Reactant
Calculate the moles of product (CH3OH) that can form
given 3.00 moles of CO reacts with 5.00 moles of H2.
What is the limiting reactant?
b. What are the mole–mole factors from these equalities?
Calculating Moles of Product from
Limiting Reactant
Calculate the moles of product (CH3OH) that can form
given 3.00 moles of CO reacts with 5.00 moles of H2.
What is the limiting reactant?
c. What is the number of moles of CH3OH from each
reactant?
Calculating Moles of Product from
Limiting Reactant
Calculate the moles of product (CH3OH) that can form
given 3.00 moles of CO reacts with 5.00 moles of H2.
What is the limiting reactant?
d. What is the limiting reactant for the reaction?
The limiting reactant is H2, which produces the smaller
number of moles of product, 2.50 moles of CH3OH.
Calculating Moles of Product from
Limiting Reactant
Calculate the moles of product (CH3OH) that can form
given 3.00 moles of CO reacts with 5.00 moles of H2.
What is the limiting reactant?