Limiting Excess and Percent Yield Problem

What is the limiting reactant if 10 moles of NH₃  react  with 30.0 moles of NO?
4NH₃+6NO --> 5N₂ + 6H₂O

• NH₃
• NO
• N₂
• water

Tags

NGSS.HS-PS1-7

The ____________ is the ratio of the actual yield to the theoretical yield that demonstrates the efficiency of the reaction.

• theoretical yield
• percent yield
• actual yield
• product

3KOH + H₃PO₄ → K₃PO₄ + 3H₂O
Calculate the theoretical mass (g) of K₃PO₄ when 100. g KOH and 250. mL of 3.30M H₃PO₄ react.

• 5.28 g K₃PO₄
• 175 g K₃PO₄
• 1130 g K₃PO₄
• 126 g K₃PO₄

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

• 1.16%
• 116%
• 85%
• 76%

The limiting reactant

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

If a chemist calculates the maximum amount of product that could be obtained in a chemical reaction, he or she is calculating the

• theoretical yield
• mole ratio
• actual yield
• percentage yield

Tags

NGSS.HS-PS1-7

When 12 moles of O₂ reacts with 1.1 mole of C₁₀H₈ what is the limiting reactant?  C₁₀H₈ + 12 O₂ --> 10 CO₂ + 4 H₂O

• Oxygen
• C₁₀H₈
• Water
• Carbon Dioxide

Tags

NGSS.HS-PS1-7

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

Tags

NGSS.HS-PS1-7

SO₂ + PCl₅ --> SOCl₂ + POCl₃
How much SOCl₂ is produced when 16.2g SO₂ react with 13.7g PCl_5? 

• 7.87g
• 30.1g
• 26.4g
• 19.8g 

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