Limiting and Excess Reactants

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

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

The limiting reactant

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

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

Tags

NGSS.HS-PS1-7

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

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

1 Cheese + 2 Bread --> 1 grilled cheese

How many grilled cheeses can you make with 26 slices of bread and 14 pieces of cheese?

• 14

• 13

• 26

A reactant that remains after a chemical reaction stops

• stoichiometry
• mole ratio
• excess reactant
• limiting reactant

Tags

NGSS.HS-PS1-7

Why is it important to identify the limiting reagent?

• The limiting reagent speeds up the reaction.

• The limiting reagent controls the amount of product formed.

• If there is no limiting reagent, the reaction will not occur.

• No stoichiometry calculations can be done without a limiting reagent.

Tags

NGSS.HS-PS1-7

Using the diagram, determine the limiting reactant, the product formed is water.

• oxygen

• hydrogen

• none of the reactant are limiting

• both hydrogen and oxygen

Tags

NGSS.HS-PS1-7

NGSS.HS-PS1-2