31) How many C2H4 molecules are contained in 45.8 mg of C2H4? The molar mass of C2H4 is 28.05 g/mol. A) 9.83 × 1020 C2H4 molecules B) 7.74 × 1026 C2H4 molecules C) 2.71 × 1020 C2H4 molecules D) 3.69 × 1023 C2H4 molecules E) 4.69 × 1023 C2H4 molecules 32) What is the mass (in kg) of 6.89 × 1025 molecules of CO2? The molar mass of CO2 is 44.01 g/mol. A) 3.85 kg B) 5.04 kg C) 2.60 kg D) 3.03 kg E) 6.39 kg 33) Calculate the mass percent composition of sulfur in Al2(SO4)3. A) 28.12 % B) 9.372 % C) 42.73 % D) 21.38 % E) 35.97 % 34) Calculate the mass percent composition of lithium in Li3PO4. A) 26.75 % B) 17.98 % C) 30.72 % D) 55.27 % E) 20.82 % 35) How many atoms of oxygen are contained in 47.6 g of Al2(CO3)3? The molar mass of Al2(CO3)3 is 233.99 g/mol. A) 1.23 × 1023 O atoms B) 2.96 × 1024 O atoms C) 2.87 × 1025 O atoms D) 1.10 × 1024 O atoms E) 3.68 × 1023 O atoms 36) How many atoms of carbon are contained in 47.6 g of Al2(CO3)3? The molar mass of Al2(CO3)3 is 233.99 g/mol. A) 1.23 × 1023 C atoms B) 2.96 × 1024 C atoms C) 2.87 × 1025 C atoms D) 1.10 × 1024 C atoms E) 3.68 × 1023 C atoms 37) How many sodium ions are contained in 99.6 mg of Na2SO3? The molar mass of Na2SO3 is 126.05 g/mol. A) 1.52 × 1027 sodium ions B) 4.76 × 1020 sodium ions C) 2.10 × 1021 sodium ions D) 1.05 × 1021 sodium ions E) 9.52 × 1020 sodium ions 38) How many SO32- ions are contained in 99.6 mg of Na2SO3? The molar mass of Na2SO3 is 126.05 g/mol. A) 1.52 × 1027 SO32- ions B) 4.76 × 1020 SO32- ions C) 2.10 × 1021 SO32- ions D) 1.05 × 1021 SO32- ions E) 9.52 × 1020 SO32- ions 39) Determine the volume of hexane that contains 5.33 × 1022 molecules of hexane. The density of hexane is 0.6548 g/mL and its molar mass is 86.17 g/mol. A) 8.59 mL B) 13.5 mL C) 7.40 mL D) 12.4 mL E) 11.6 mL 40) How many molecules of butane are contained in 25.0 mL of butane? The density of butane is 0.6011 g/mL and the molar mass is 58.12 g/mol. A) 2.59 × 1023 molecules butane B) 1.46 × 1027 molecules butane C) 6.87 × 1023 molecules butane D) 1.56 × 1023 molecules butane E