Chem I Worksheet #40 Stoichiometry (Mass Calculations) Name ________________________
Text Reference pgs 275-281
1.
Although mixtures of hydrogen and oxygen are highly explosive, pure elemental hydrogen gas itself
burns quietly in air with a pale blue flame, producing water vapor.
2H2(g) + O2(g)  2H2O(g)
Calculate the mass in grams of water vapor produced when 56.0 g of pure hydrogen gas burns.
2.
When elemental carbon is burned in the open atmosphere, with plenty of oxygen gas present, the
product is carbon dioxide.
C(s) + O2(g)  2CO2(g)
However, when the amount of oxygen present during the burning of the carbon is restricted, carbon
monoxide is more likely to result.
2C(s) + O2(g)  2CO(g)
What mass of each product is expected when a 5.00g sample of pure carbon is burned under each of these
conditions?
3.
Although we usually think of substances as "burning" only in oxygen gas, the process of rapid
oxidation to produce a flame may also take place in other strongly oxidizing gases. For example, when
iron is heated and placed in pure chlorine gas, the iron "burns" according to the following (unbalanced)
reaction.
Fe(s) + Cl2(g)  FeCl3(s)
How many milligrams of Iron(III) chloride result when 15.5 mg of iron is reacted with an excess of
chlorine gas?
4.
Using the average atomic masses given inside the front cover, calculate how many moles of each
element the following masses represent.
a.
19.5 g of gold
b.
11.78 g of iron
c. 2.395 g of carbon dioxide
d.
1.0 kg of barium chloride
e.
1.0 mg of magnesium
5.
For each of the following balanced reactions, calculate how many moles of each product would be
produced by complete conversion of 5.00grams of the reactant indicated in boldface. The other
reactant is in excess.
a.
2C2H5OH(l) + 7O2(g)  4CO2(g) + 6H2O(g)
b.
N2(g) + O2(g)  2NO(g)
c.
2NaClO2(s) +Cl2(g)  2ClO2(g) + 2NaCl(s)
d.
3H2(g) + N2(g)  2NH3(g)
6.
For each of the following balanced reactions, calculate how many moles of each product would be
produced by complete conversion of 1.50grams of the reactant indicated in boldface. The other
reactant is in excess.
a.
2H2O2(l)  2H2O(l) + O2(g)
b.
2KClO3(s)  2KCL(s) + 3O2(g)
c.
2Al(s) + 6HCL9aq)  2AlCl3(aq) + 3H2(g)
d. C3H8(g) + 5O2(g)  3CO2(g) +4H2O(g)