Stoichiometry and Limiting Reactants

What is the first thing you must do to solve a stoichiometry problem?

• Write a Balanced Equation
• Panic
• Write an Unbalanced Equation
• Avogadro's Number

Balance the following reaction :
 
CaC₂(s)   +   H₂O(l)   -->   C₂H₂(g)   +   Ca(OH)₂(aq)

• 1,2,2,2
• 1,2,1,1
• 2,1,1,1
• 2,1,2,1

What is the mole ratio of H₂O to H₃PO₄ in the following chemical equation?   P₄O₁₀ + 6 H₂O --> 4 H₃PO₄ 

• 6:4
• 4:6
• 1:3
• 3:1

Using the following equation:
Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)
How many moles of iron can be made from  6 moles H₂? 

• 4 moles Fe
• 6 moles Fe
• 9 moles Fe
• 2 moles Fe

2Al + 3H₂SO₄ -> Al₂(SO₄)₃ + 3H₂
How many grams of aluminum sulfate would be formed if 250g H₂SO₄ completely reacted with aluminum?

• 0.85 g
• 290 g
• 450 g
• 870 g

When reacting Na with Cl₂, we calculated that the theoretical yield should be 12.5 grams. Our actual yield was 13.0 grams. What is the percent yield?

• 100%
• 104%
• 96%
• 1.04

In a lab, a scientist calculate he should produce 12.3 grams of product in his experiment. When he is finished collecting his product it weighs 10.1 grams. What is his percent yield?

• 82%
• 0.82%
• 10.1 %
• 100%

Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield.

• 1.16%
• 116%
• 85%
• 76%

Fe + S --> FeS
If 7.62g Fe react with 8.67g S, what is the limiting reactant?

• Fe
• S
• FeS
• none 

CH₄ + 2H₂O --> CO₂ + 4H₂
What is the limiting reactant when 20g CH₄ react with 15g H₂O?

• CH₄
• H₂O
• CO₂
• H₂