Limiting 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

A limiting reactant is a reactant that.....

• runs out during a chemical reaction

• causes a reaction to stop

• determines the amount of products that can be made

• all of these

Fe + S --> FeS
If 7.62g Fe react with 8.67g S, what is the limiting reactant?

• Fe

• S

• FeS

• none 

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

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

When the limiting reactant is used up, what happens?

• the reaction speeds up

• the reaction slows down

• the reaction moves to its 2nd stage

• the reaction stops

Which reactant is the limiting reagent and why?

• Hydrogen is the limiting reagent because two moles of hydrogen is required for every one mole of oxygen to produce two water.

• Oxygen is the limiting reagent because two moles of hydrogen is required for every one mole of oxygen to produce two water.

Tags

NGSS.HS-PS1-2

• None, they are in perfect stoichiometric ratio

Tags

NGSS.HS-PS1-7

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

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

Answer explanation

The limiting reactant is Oxygen because it is consumed first in the reaction. Here you use the mole ratios from the balanced equation to determine proportions.