Practice Quiz #2 Stoichiometry (Limiting Reactant & % Yield)

Using the following equation:

Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)

How many moles of Fe can be made from 6.0 moles H₂? (This is a one step conversion using mole ratio)

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• 4.0 moles Fe

• 6.0 moles Fe

• 9.0 moles Fe

• 2.0 moles Fe

Cl₂ + 2KBr → Br₂ + 2KCl

How many grams of KCl can be produced from 356 g of KBr? (This is a three step conversion from grams to moles, mole ratio, and then moles to grams)

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• 749 g

• 223 g

• 479 g

• 814 g

Use the following reaction: N₂ + 3 H₂ → 2 NH₃

What is the correct number of moles of H₂ that is reacted to produce 13.2 moles of ammonia (NH₃) in the presence of excess of nitrogen?

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• 19.8 mol

• 8.80 mo

• 13.2 mol

• 6.6 mol

CH₄ + 2 O₂ → CO₂ + 2 H₂O

How many moles of carbon dioxide are produced from the combustion of 110 g of CH₄?

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• 14 mol

• 2.8 mol

• 6.1 mol

• 6.9 mol

When does a chemical reaction stop?

• When the lab is finished
• When the excess reactant is used up
• When the limiting reactant is used up
• Chemical reactions never stop

Tags

NGSS.HS-PS1-6

The limiting reactant

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

What is the limiting reactant if 10 moles of NH₃ react with 30.0 moles of NO?

4NH₃+6NO --> 5N₂ + 6H₂O

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• NH₃

• NO

• N₂

• water

Theoretical yield = 73g

Actual yield = 62g

Calculate the percent yield.

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• 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

Tags

NGSS.HS-PS1-7

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

• CH₄
• H₂O
• CO₂
• H₂

Tags

NGSS.HS-PS1-7