Chemistry Quiz: Atomic Mass and Molar Mass

Question 1: Calculate the formula mass of CaCl2. (Atomic mass of Ca = 40.08 g/mol, Cl = 35.45 g/mol)

• 110.98 g/mol

• 55.34 g/mol

• 90.08 g/mol

• 75.53 g/mol

Question 2: Find the formula mass of H2SO4. (Atomic mass of H = 1.01 g/mol, S = 32.07 g/mol, O = 16.00 g/mol)

• 56.05 g/mol

• 84.98 g/mol

• 72.12 g/mol

• 98.09 g/mol

Question 3: Determine the formula mass of Al2(SO4)3. (Atomic mass of Al = 26.98 g/mol, S = 32.07 g/mol, O = 16.00 g/mol)

• 412.50 g/mol

• 342.15 g/mol

• 256.78 g/mol

• 180.32 g/mol

Question 4: Calculate the average atomic mass of carbon. (Isotopes: C-12 with 98.89% abundance, C-13 with 1.11% abundance)

• 14.03 u

• 12.01 u

• 6.02 u

• 10.05 u

Question 5: Find the average atomic mass of chlorine. (Isotopes: Cl-35 with 75.77% abundance, Cl-37 with 24.23% abundance)

• 40.25 amu

• 32.60 amu

• 38.90 amu

• 35.45 amu

Question 6: Determine the average atomic mass of lithium. (Isotopes: Li-6 with 7.59% abundance, Li-7 with 92.41% abundance)

• 10.25

• 5.67

• 6.94

• 3.14

Question 7: Calculate the molar mass of water (H2O). (Atomic mass of H = 1.01 g/mol, O = 16.00 g/mol)

• 10.50 g/mol

• 12.04 g/mol

• 20.00 g/mol

• 18.02 g/mol

Question 8: Find the molar mass of carbon dioxide (CO2). (Atomic mass of C = 12.01 g/mol, O = 16.00 g/mol)

• 44.01 g/mol

• 36.02 g/mol

• 24.01 g/mol

• 50.00 g/mol

Question 9: Explain the concept of moles in atomic mass calculations.

• Moles are small underground animals that help in atomic mass calculations

• Moles are the marks left by chemicals on a surface during atomic mass calculations

• Moles are the unit used to measure temperature in atomic mass calculations

• Moles are used to measure the amount of a substance and convert between mass and the number of atoms or molecules.

Question 10: How are moles used to calculate the molar mass of compounds?

• By dividing the molar mass by the number of moles

• By adding the atomic masses of each element in the compound

• By counting the number of moles in the compound

• By multiplying the number of moles of each element by its atomic mass and then adding them together.