Mastering Stoichiometry Concepts

What is the number of particles in one mole of a substance?

• 6.022 x 10^23

• 1.00 x 10^24

• 3.14 x 10^22

• 6.022 x 10^22

How do you convert grams of a substance to moles?

• moles = grams / molar mass

• moles = grams + molar mass

• moles = grams - molar mass

• moles = grams * molar mass

Balance the following equation: C3H8 + O2 → CO2 + H2O.

• C3H8 + 3 O2 → 2 CO2 + 3 H2O

• C3H8 + 5 O2 → 3 CO2 + 4 H2O

• C3H8 + 4 O2 → 2 CO2 + 5 H2O

• C3H8 + 6 O2 → 4 CO2 + 2 H2O

What is the limiting reactant in the reaction: 2H2 + O2 → 2H2O if you have 3 moles of H2 and 1 mole of O2?

• H2O

• O2

• 2H2

• H2

Calculate the number of moles in 50 grams of NaCl.

• 1.2 moles

• 0.855 moles

• 0.5 moles

• 0.75 moles

If 4 moles of A react with 3 moles of B, how many moles of C are produced in the reaction A + 2B → C?

• 2 moles of C

• 1.5 moles of C

• 4 moles of C

• 3 moles of C

What is the percent yield if 10 grams of product were obtained from a theoretical yield of 15 grams?

• 66.67%

• 80%

• 75%

• 50%

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

• The reactant that is present in equal amounts to the other reactants.

• The reactant that is present in a greater amount than needed based on stoichiometric calculations.

• The reactant that is completely consumed in the reaction.

• The reactant that produces the least amount of product.

In the reaction 2H2 + O2 → 2H2O, how many liters of O2 are needed to react with 10 liters of H2 at STP?

• 1 liter of O2

• 5 liters of O2

• 10 liters of O2

• 2.5 liters of O2

What is the molar mass of CaCO3?

• 98.00 g/mol

• 100.09 g/mol

• 102.05 g/mol

• 95.50 g/mol