Stoichiometry Test Review

What is a limiting reactant?

• the reactant that determines how much product can be made
• the reactant that is in excess
• the product that you can make the most of
• the amount of reactants that react with each other

2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

• 5.2 g
• 2.6 g
• 690 g
• 45 g

B₂H₆ + 3O₂ -->2 HBO₂ + 2 H₂O
 What mass of O₂ will be needed to burn 36.1 g of B₂H₆?

• 13.8 g O₂
• 3.86 mol of O₂
• 124 g O₂
• 62 g O₂

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

Tags

NGSS.HS-PS1-7

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%

When reacting Na with Cl₂, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?

• 90.4%

• 104%

• 96.15%

• 1.04%

Tags

NGSS.HS-PS1-7

Students recorded their observations below for before and after the reaction. The balanced equation can be found below: Al + CuSO₄ --> AlSO₄ + Cu. Determine which of the following is the limiting reactant and why.

Before Reaction: silver colored foil (aluminum) flat sheet, blue colored solution

After reaction: Rust colored solid with some silver solid within, solution is now clear

• Copper sulfate is limiting because, after reaction, no copper sulfate is visible.

• Copper sulfate is limiting because, after reaction, the solution has become blue, indicating the presence of a copper-containing compound.

• Aluminum is limiting because, after reaction, no more aluminum remains.

• Aluminum is limiting because, after reaction, the solution has become blue, indicating the presence of a copper-containing compound.

For the Balanced Reaction: 3 Mg + 1 Fe₂O₃ → 3 MgO + 2 Fe; What molar ratios are correct?

• 3 mol Mg

  2 mol Fe

• 2 mol Mg

  3 mol Fe

• 3 mol Mg

  3 mol MgO

• 3 mol MgO

  2 mol Fe

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

• 256 g O₂

• 576 g O₂

• 288 g O₂
• 18 g O₂

Tags

NGSS.HS-PS1-7

If 5.2 grams of Mn(SO₄)₂ are actually formed in the lab, what is the percent yield?

The calculated number of grams for Mn(SO₄)₂ is 6.30 grams

• 37%

• 48%

• 53%

• 83%

Tags

NGSS.HS-PS1-7