Pre-AP Chemistry Exam #9 - Moles

A compound's empirical formula is CO2. If the molar mass of the compound is 220 grams, determine the molecular formula:

• C2O4
• CO2
• C5O10
• C3O6

The number of moles present in a 43.8 gram sample of aluminum bromide would be -

• 1.5 moles
• 10 moles
• 0.002 moles
• 0.16 moles

Determine the empirical formula for an unknown compound that is 41.9% potassium, 38.9% chlorine, and 20.1% oxygen:

• K2ClO3
• KClO
• K2Cl2O
• KCl2O2

What is the percent of zinc in the compound zinc oxide?

• 80.34%

• 25%
• 50%
• 10%

One sample of dish soap contains 0.048 grams of boron. Determine the total number of moles in this boron sample.

• 0.048 grams of boron is equivalent to 0.005 moles

• 0.048 grams of boron is equivalent to 0.0001 moles
• 0.048 grams of boron is equivalent to 0.0044 moles

• 0.048 grams of boron is equivalent to 0.000775 moles

What is the molar mass of Iron (III) phosphate?

• 150.82 g/mol
• 210.56 g/mol
• 98.76 g/mol
• 65.38 g/mol

How many atoms would be present in one mole of oxygen gas?

• 6.02 x 10^23 atoms

• 1.81 x 10^24 atoms

• 124.9 atoms

• 22.4 atoms

The mass of three moles of calcium hydroxide is approximately -

• 100.567 g
• 300.890 g
• 150.345 g
• 222.279 g