Calculations involving moles, masses, and volumes of both reactants and
products in a chemical equation.
The balanced chemical equation indicates the MOLE RATIOS of the reactants
and products
Example:
2 CuO
1 O2
2 Cu
+
Coefficents indicate the number of moles. (in blue)
i.e.
2 mol Cu : 1 mol O2 : 2 mol CuO
How many moles of copper (II) oxide can be produced from 0.50 moles of
oxygen gas?
? Mol CuO = 0.50 mol O2 x 2 mol CuO = 1.0 mol CuO
1 mol O2
How many moles of copper would be required to produce 2.10x10-2 moles of
copper (II) oxide?
? Mol Cu = 2.10x10-2 mol CuO x 2 mol Cu
2 mol CuO
= 2.1x10-2 mol CuO
A. Mole to Mole Calculations
Example:
3 H2(g)
+
N2(g)
2 NH3(g)
How many moles of NH3 are formed when 6.5 mol N2 are reacted with a large
excess of H?
? Mol NH3 = 6.5 mol N2 x 2 mol NH3
1 mol N2
= 13 mol NH3
Note: The proportions from the balanced equation are
NOT for masses
Reaction Calculations Worksheet. In-class Assignment.
P.154 #1-6. Homework.
2 AgNO3(aq) +
Cu(s)
Cu(NO3)2(aq) +
2 Ag(s)
How many moles of AgNO3 would be required to produce 3.2x10-2 mol
of Cu(NO3)2?
3.2x10-2 mol Cu(NO3)2 x 2 mol AgNO3 = 6.4x10-2 mol AgNO3
1 mol Cu(NO3)2
What mass of AgNO3 would be required to produce 0.020 mol of
Cu(NO3)2?
1) Determine the moles of AgNO3 required.
0.020 mol Cu(NO3)2 x 2 mol AgNO3
1 mol Cu(NO3)2
= 0.040 mol AgNO3
2) Convert moles of AgNO3 to mass.
0.040 mol AgNO3 x 169.9 g
1 mol
= 6.8g AgNO3
Or you can put both steps together.
0.020 mol Cu(NO3)2 x 2 mol AgNO3 x 169.9 g
1 mol Cu(NO3)2
1 mol
= 6.8g AgNO3
If we need to produce 5.0g of silver, what mass of copper would be
needed?
mass Ag
mol Ag
Use molar
mass of Ag
5.0g Ag
mol Ag
107.9g Ag
mol Cu
Use balanced
equation
1 mol Cu
2 mol Ag
63.5g Cu
mol Cu
mass Cu
Use molar
mass of Cu
= 1.5g Cu
Classwork:
– Chem 11 Worksheet
Homework:
– Read Lab 6B
– There will be a Pre-lab Quiz