Mole Conversions & Percent Composition Practice

Multiple Choice

What is the percent by mass of sodium in NaCl?

• 39%
• 61%
• 35%
• 65%

Multiple Choice

What is the percent by mass of oxygen in MgO?

• 20%
• 40%
• 50%
• 60%

Multiple Choice

If 13.5g of carbon fully reacts with 36.5g of oxygen to form carbon dioxide, what is the percentage by mass of carbon in the sample?

• 73%

• 27%

• 44%

• 31%

Multiple Choice

Which conversion factor should be used to solve the following, "How many moles of argon atoms are present in 11.2 L of argon gas at STP?"

• 1 mol = 22.4 L

• 1 mol = 39.95 g

• 1 mol = 6.02x10²³ atoms

• More than 1

Multiple Choice

You have 3.5 L of H₂ (g) at STP. How many moles of gas are there?

• 22.4 mol

• 22.4 L

• 0.16 mol

• 0.16 L

Multiple Choice

What is the volume of 2 moles of gas at STP?

• 22.4 L

• 44.8 L

• 11.2 L

• 2 L

Multiple Choice

What is the mass of one mole of silver?

• 32.06 g

• 107.87 g

• 14.01 g

• 22.99 g

Multiple Choice

What is the molar mass of AuCl₃?

• 96 g

• 130 g

• 232.5 g

• 303.3 g

Multiple Choice

How many molecules of sugar (C₆H₁₂O₆) are in a mole?

• 24 molecules

• 180 molecules

• 180 g

• 6.02 x 10²³ molecules

Multiple Choice

48.86 g of cobalt is equal to how many moles of cobalt?

• 2879 moles

• 8.291 moles

• .8291 moles

• .829 moles

Multiple Choice

Convert 86.235 g of diphosphorus pentaoxide to moles.

• 12240 moles

• 1.8747 moles

• .608 moles

• .60755 moles

Multiple Choice

How many moles of sodium chloride (NaCl) are in a 321.8 g sample?

• 18810 moles

• 3.315 x 10²⁴ moles

• 5.507 moles

• 4.767 moles

Multiple Choice

What is the mass of 4.98 x 10²⁴ atoms of Zn?

• 541 g

• 8.27 g

• .122 g

• 4.59 x 10⁴⁶ g

Multiple Choice

how many molecules of CO₂ are contained in a 456 g sample of carbon dioxide?

• 10.34 atoms

• 6.237 x 10²⁴ atoms

• 1.871 x 10²⁵atoms

• 2.079 x 10²⁴ atoms

Multiple Choice

How many formula units of calcium chloride (CaCl₂) are in a 25.69 g sample?

• 1.394 x 10²³ F.U.'s

• 2851 F.U.'s

• .2315 F.U.'s

• 3.845 x 10²⁵ F.U.'s

Multiple Choice

How many molecules of water are in a 821.3 g sample?

• 45.58 molecules

• 8.232 x 10²⁵ molecules

• 8.909 x 10²⁷ molecules

• 2.744 x 10²⁵ molecules