12.3 Limiting Reagent

1. What is a limiting reagent?

• any reactant used up first in a reaction.
• any reactant left over at the end of a reaction.
• the maximum amount of product formed from a given amount of reactant.
• the purity of the reactant.

Tags

NGSS.HS-PS1-7

The reactant that is not completely used up in a chemical reaction is called the __________ .

• spectator reagent

• limiting reagent

• excess reagent

• catalyst

When 12 moles of O₂ reacts with 6 moles of C₁₀H₈, what is the limiting reactant?  
1 C₁₀H₈ + 12 O₂ --> 10 CO₂ + 4 H₂O

• Oxygen
• C₁₀H₈
• Water
• Carbon Dioxide

Tags

NGSS.HS-PS1-7

Use the equation 2 Al + 3 Cl₂ ---> 2 AlCl₃.  If 2 moles of aluminum and 2 moles of chlorine are reacted, identify the limiting reactant.

• AlCl₃
• Cl₂
• Al
• None

Tags

NGSS.HS-PS1-7

Identify the limiting reagent when 6.00 moles HCl combines with 5.00 moles Mg to form MgCl₂.
 
1 Mg +  2 HCl --> 1 MgCl₂  +  1 H₂   
 

• Mg
• H₂
• MgCl₂
• HCl

Tags

NGSS.HS-PS1-7

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

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

• 1.16%
• 116%
• 85%
• 76%

Tags

NGSS.HS-PS1-7

What is the measured amount of a product obtained from a chemical reaction?

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

Tags

NGSS.HS-PS1-7

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 the percentage yield for a chemical reaction is 80.0%, the 

• actual yield is 80.0g for every theoretical yield of 100g.
• actual yield is 80 times as much as the theoretical yield.
• theoretical yield is 80 times as much as the actual yield. 
• theoretical yield is 80.0 g for every actual yield of 100g.

Tags

NGSS.HS-PS1-7