Download Honors Chemistry: Ch. 12 – Stoichiometry Some useful terms

Honors Chemistry: Ch. 12 – Stoichiometry
I.
Some useful terms…..
Stoichiometry – calculations based on balanced equations
Mole Ratio – conversion factor derived from coefficients of a balanced chemical equation
used to convert between moles of reactants to moles of products.
Ex:
II.
N2(g) + 3 H2(g)  2 NH3(g)
1 mole N2
3 mole H2
CALCULATIONS:
1.) Mole to Mole
Ex: Using the above chemical reaction, if I had 3 moles of nitrogen how many moles
of ammonia would I have?
a.) 3 mol N2 x
mol NH3
mol N2
b.) 3 mol N2 x
2 mol NH3
1 mol N2
=
6 mol NH3
** Use coefficients!!
2.) Mass to Mass
Ex: Based on the same reaction, calculate the number of grams of NH3 produced by
5.40g of Hydrogen.
a.) 5.40 g H2
x
b.) 2.70 mol H2
c.) 1.80 mol NH3
1 mol H2
2.0 g H2
x
2 mol NH3
3 mol H2
x
= 2.70 mol H2
= 1.80 mol NH3
17.0 g NH3
1 mol NH3
=
31.0 g NH3
**Steps: grams (reactants)  mol (reactants)  mol (products) grams (product)
3.) Volume to Volume
Ex: 2 NO (g) + O2(g)  2NO2 (g)
If I start with 34.0 liters of oxygen, how many liters of NO2 are there?
a.) 34.0 L O2
x 1 mol O2 = 1.52 mol O2
22.4 L
b.) 1.52 mol O2 x 2 mol NO2 = 3.04 mol NO2
1 mol O2
c.) 3.04 mol NO2
x
22.4 L =
1 mol NO2
68.0L NO2
**Steps: liter (reactants)  mol (reactants)  mol (products) liter (product)
12.2 Practice Problems
1.) How many moles of chlorine gas will be required to react with sufficient iron to produce
14 moles of iron (III) chloride?
2Fe (s) + 3 Cl2(g)  2 FeCl3 (g)
2.) How many liters of carbon monoxide (at STP) are needed to react with 4.8g of oxygen
gas to produce carbon dioxide?
2CO(g) + O2(g)  2CO2(g)
3.) What mass of ammonia is necessary to react with 2.1 x 1024 molecules of oxygen in the
following reaction?
4NH3 (g) + 7O2 (g)  6 H2O(g) + 4 NO2 (g)
Homework: Please complete on a separate sheet of paper to show all work.
1.) Calculate the number of moles of hydrogen chloride produced from 10 moles of
hydrogen.
H2(g) + Cl2(g)  2 HCl(g)
2.) Calculate the number of grams of nitrogen dioxide that are produced from 4 moles of
nitric oxide.
2NO(g) + O2(g)  2NO2(g)
3.) Calculate the mass of oxygen produced from the decomposition of 75.0 g of
potassium chlorate.
2KClO3(s)  2 KCl(s) + 3O2(g)
4.) Calculate the mass of silver needed to react with chlorine to produce 84 g of silver
chloride (Hint: Write a balanced equation first).
5.) Calculate the number of liters of oxygen gas needed to produce 15.0 liters of
dinitrogen trioxide. Assume all gases are at STP.
2N2(g) + 3O2(g)  2N2O3(g)
6.) A volume of 7.5 L of hydrogen gas was produced from the single-replacements
reaction of zinc with nitric acid. Calculate the mass of zinc needed for this reaction.