This document provides instructions for completing mass-to-mass stoichiometry problems using chemical reactions. It includes a sample reaction of sulfur reacting with oxygen and hydrogen to form sulfuric acid, along with 5 practice problems using this reaction. It instructs students to show their work and uses the steps of converting between grams and moles, using mole ratios from the balanced chemical equation, and converting between moles and grams.

1. Name ________________________________
Mass-to-Mass Worksheet
Start with # N2 (g) + 3H2 (g) → 2NH3 (g)
and unit given
5.40 g H2 1 mol H2 2 mol NH3 17.03 g NH3 1) Molar mass
to convert from = 31 g NH3
2.02 g H2 3 mol H2 1 mol NH3 mol back to g
2) Molar mass
to convert g to 3) Use mole ratio to
moles go from 1 substance to
the next substance
…remember…first step (g to mole)…mole ratio…third step (mole to g)…only sometimes you don’t do
some of that… Work must be shown on every problem that has calculations…no work = no credit
Use the following reaction for problems 1-4…
S8 (s) + O2 (g) + H2 (g) →H2SO4 (aq)
1. In the synthesis of sulfuric acid 15.3 mol of sulfur react completely.
a. How many moles of oxygen are should be used? (Hint: 2nd step only)
b. How many moles of sulfuric acid can be made from the complete reaction of sulfur?
(Hint: 2nd step only)
c. How many grams of sulfuric acid can be made? (hint: second and third steps)
2. How many moles of sulfuric acid are made the burning of 87.1 grams of sulfur (S8)? (hint: 1st
and 2nd steps)
3. How many grams of sulfuric acid could be made from 435 grams of oxygen gas? (hint: all three
steps)
4. How many grams of sulfuric acid could be made from 65.9 grams of hydrogen gas? (hint: all
three steps)
5. Write and balance the reaction that occurs between iron (III) chlorate solution and potassium
hydroxide solutions.
a. How many moles of iron (III) hydroxide can be recovered if 14.2 moles of potassium
hydroxide were used up? (Hint: second step only)
b. What mass of iron (III) hydroxide will precipitate out from 1.35 x 10-3 moles of iron (III)
chlorate? (hint: second and third steps)
c. How many grams of potassium chlorate could be recovered from 396.5 grams of iron
(III) chlorate? (hint: all three steps)