Intro to Stoichiometry Review (2019)

Which statement is FALSE about this chemical reaction?

• 2 moles of hydrogen molecules will react with 1 mole of oxygen molecules.

• 2 grams of hydrogen will react with 1 gram of oxygen.

• For every 2 moles of hydrogen molecules that react, 2 moles of water molecules will be produced.

What is the mole ratio of Aluminum to Hydrogen chloride in this reaction?

2 Al + 6 HCl → 3 H₂ + 2 AlCl₃

• 2 moles Al :6 moles HCl

• 26.98 moles Al : 36.46 moles HCl

• 2 moles Al :3 moles HCl

What is the percent by mass of calcium in CaF₂ ?

• 24%

• 49%

• 51%

• 65%

If the molar mass of Zn₃(PO₄)₂ is 386.17g , what is the percent composition of oxygen in zinc phosphate?

• 33.15%

• 16.04%

• 50.81%

• 19.68%

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

What is the empirical formula if you have 36.84% nitrogen and 63.16% oxygen?

• NO
• N₂O₃
• N₂O₄
• N₂O₅

An empirical formula:

• is a formula that calculates the coefficients of a compound in a balanced equation.
• is the simplest whole-number ratio of moles of elements in the compound.

What is the empirical formula if you have 88.80% copper and 11.20% oxygen?

• Cu₃O₈
• CuO₄
• Cu₂O
• Cu₄O₁₀

Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula.

• NaPO₂
• Na₂PO₃
• Na₃PO₄
• NaPO₄

What is the mass of one mole of aluminum?

• 26.98 g

• 13 g

• 53.98 g

• 14 g