Practice stoichiometry

Using the unbalanced equation in question 1,

Mg(s) + 2HCl(aq) --> MgCl₂(aq) + H₂(g)

What is the mass in grams of H₂ gas when 4.0 moles of HCl is added to excess magnesium in the reaction?

• 0.99 g

• 4.0 g

• 2.0 g

• 6.0 g

Using the unbalanced equation in question 9,

C₂H₂(g) + O₂(g) --> CO₂(g) + H₂O(g)

How many moles of water (H₂O) are produced when 25.0 grams of C₂H₂ are consumed?

• 0.960 moles

• 0.480 moles

• 1.92 moles

• 3.84 moles

Given the following reaction, 2 NaClO₃ (s) --> 2NaCl (s) +3 O₂ (g)  12.00 moles of NaClO₃ will produce how many grams of O₂?

• 256 g of O₂
• 576 g of O₂
• 288 g O₂

Use the following equation:
2NaOH(aq) + H₂SO₄(aq) --> 2H₂O(l) + Na₂SO₄(aq)
How many grams of sodium sulfate will be formed if you start with 200 grams of sodium hydroxide?

• 150.22 g Na₂SO₄
• 593.44 g Na₂SO₄
• 330.04 g Na₂SO₄
• 297.65 g Na₂SO₄

2 KClO₃ → 2 KCl + 3 O₂
How many moles of oxygen are produced when 6.7 moles of KClO₃ decompose completely?

• 6.7 mol
• 1.0 mol
• 10.1 mol
• 4.5 mol

The limiting reactant

• slows the reaction down
• is used up first
• is the reactant that is left over
• controls the speed of the reaction

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

• 1.16%
• 116%
• 85%
• 76%

P₄ + 3O₂ --> P₄O₆ 
What is the limiting reactant is 12 moles of P₄ react with 15 moles of O₂?

• P₄
• O₂
• P₄O₆ 
• none of the above

4NH₃ + 5O₂ --> 4NO + 6H₂O
How many grams of NO are formed if 6.30g of ammonia react with 1.80g of oxygen? 

• 0.37g
• 0.045g
• 1.35g
• 11.1g

P₄ + 6Cl₂ --> 4PCl₃

The reaction of 75.0g P₄ with excess chlorine gas produces 110g PCl₃ in lab. What is the percent yield for the reaction?

• 78%

• 64%

• 27%

• 33%