Limited Reactants

What are the correct steps for determining the limiting reactant?

• divide each reactant by its molar mass and look for the smallest number

• balance the chemical equation and look for the smallest coefficient

• divide the moles of each reactant by its coefficient and look for the smallest number

• divide each reactant by Avogadro's number and look for the smallest number

What is the limiting reactant if 15 GRAMS of NH₃ react with 16 GRAMS of NO?
4NH₃+6NO --> 5N₂ + 6H₂O
(Remember, convert grams to moles, then divide each substance by the number of moles given as the coefficient from the balanced chemical equation).

• NH₃ is the limiting because the reaction only requires 0.22 mol of NH₃

• NO is the limiting reactant because the reaction only requires 0.088 mol NO 

• NH₃ is the limiting because the reaction only requires 0.88 mol of NH₃

• NO is the limiting reactant because the reaction only requires 0.53 mol NO 

A chemical reaction involving substances A and B stops when B is completely used.  B is the

• excess reactant

• primary reactant

• limiting reactant

• primary product

How do you determine the limiting reactant?

• Find the amount of product produced by each amount of reactant. The reactant that makes the most is the limiting reactant.

• Find the amount of product produced by each amount of reactant. The reactant that makes the least is the limiting reactant.

• The reactant with the least amount of mass (grams) present is the limiting reactant.

• Cannot be determined.

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-PS1-7

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-PS1-7

The limiting reactant

• .
• is used up first
• is the reactant that is left over
• .

Body + 4 Tires --> 1 car
How many cars can you make with 92 tires and 34 bodies? 
In this senario the tires would be the _____________  reactant. 

• Limiting 

• Excess 

Tags

NGSS.MS-PS1-5

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

True or False?
A chemical reaction stops before the limiting reagent is used up.

• True

• False