Limiting/Excess

Which of the following describes an excess reactant?

• The reactant that is not completely consumed during a reaction

• None of this reactant is left over after the reaction take place

• The reactant that is completely consumed during the reaction

Which of the following describes a limiting reactant?

• The reactant that is not completely consumed during a reaction

• The reactant that is completely consumed during the reaction

• Some of this reaction is left over after the reaction

In stoichiometry, what step always come after your unit is in moles?

• molar mass

• mole to mole ratio

• percent yield

• coefficients

Hydrogen and oxygen molecules combine to form water molecules as shown in the reaction below. Given the molecules provided, which of the following is true about the products of this reaction? 

• 2 H₂O molecules are produced, O₂ is the limiting reactant

• 4 H₂O molecules are produced, H₂ is the limiting reactant

• 4 H₂O molecules are produced, O₂ is the limiting reactant

• 6 H₂O molecules are produced, H₂ is the limiting reactant

Tags

NGSS.HS-PS1-7

Which of the following is NOT part of a conversion factor we studied that equals 1 mole?

• grams from the periodic table

• 22.4 Liters

• 22.4 meters

• 6.02 x 10^23 particles (atoms, molecules)

In this image, what is the information to the right of the arrow (in black) is called the_______.

• Product

• Reactant

• Chemical Subscript

• Yield

Tags

NGSS.MS-PS1-2

The ____ in a balanced chemical reactions gives the MOLE RATIO used in stoichiometry problems.

• coefficients

• reactants

• subscripts

• products

CH₄ + 2H₂O --> CO₂ + 4H₂

What is the limiting reactant when 20g CH₄ and 15g H₂O are combined? (CH₄ = 16.05 g/mol; H₂O = 18.02 g/mol) Hint: Calculate the moles of each. The answer with the smallest number is the limiting reactant.

• CH₄

• H₂O

• CO₂

• H₂

Fe + S --> FeS If 7.62g Fe react with 8.67g S, what is the limiting reactant? Hint: Calculate the moles for Fe and S. The answer with the smallest number is the limiting reactant.

• Fe

• S

• FeS

• none 

Tags

NGSS.HS-PS1-7

It refers to the substance(s) that are considered to be "ingredients" of a chemical reaction.

• reactants

• products

• catalysts

• enhancers

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5