What is the excess reactant in a chemical reaction?

• The reactant that is completely consumed in the reaction

• The product of the reaction

• The reactant that is present in a greater amount than necessary for the reaction to occur.

• The catalyst used in the reaction

Calculate the theoretical yield of a reaction if 5.0g of A reacts with 8.0g of B and the reaction has a 90% yield.

• 6.7g

• 2.3g

• 4.5g

• 11.7g

Tags

NGSS.HS-PS1-7

Identify the limiting reactant in the following chemical reaction: 2A + 3B → 4C, if 10 moles of A and 15 moles of B are present.

• A & B

• B

• C

• A

Solve for the percent yield if the actual yield of a reaction is 25g and the theoretical yield is 30g.

• 100%

• 83.33%

• 50%

• 20%

Tags

NGSS.HS-PS1-7

Using stoichiometry, find the limiting and excess reactants in the reaction: 2C + 3D → 4E, if 8 moles of C and 12 moles of D are present.

• Both C and D are limiting reactants.

• D is the limiting reactant and C is the excess reactant.

• Neither C nor D are limiting reactants.

• C is the limiting reactant and D is the excess reactant.

How do you determine the excess reactant in a chemical reaction?

• By ignoring the stoichiometric ratio and randomly choosing a reactant

• By comparing the amount of each reactant to the stoichiometric ratio and identifying which reactant is present in excess.

• By measuring the temperature of the reaction mixture

• By asking someone else to determine it

Identify the limiting reactant in the following chemical reaction: A + 2B → 3C, if 12 moles of A and 8 moles of B are present.

• A + 2B

• A

• C

• B

Using stoichiometry, find the limiting and excess reactants in the reaction: 3X + 2Y → 5Z, if 15 moles of X and 10 moles of Y are present.

• Y is the limiting reactant and X is the excess reactant.

• Both X and Y are limiting reactants.

• Neither X nor Y are limiting or excess reactants.

• X is the limiting reactant and Y is the excess reactant.

The limiting reactant

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

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