# Sample Quiz Chem105

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1. Calculate the average atomic mass of silver using the following data: |Isotope |Abundance |Mass | |107Ag |51.84% |106.9051amu | |109Ag |48.16% |108.9048amu | |106.91 amu • 107.87 amu • 108.00 amu • 108.90 amu What is the average mass of one S atom? • 32.07 g • 32.07 amu • 32.07 g/mol • 32.07 mol What is the mass of 3.50 x 1024 Ti atoms? • 47.9 amu • 47.9 g • 5.81 g • 278 g How many C atoms are in 5.50 g of C? • 5.01 x 1022 C atoms • 2.76 x 1023 C atoms • 3.31 x 1024 C atoms • 5.50 x 1023 C atoms How many Cl atoms are in 0.0728 g of PCl3? • 1.32 x 1023 Cl atoms • 3.19 x 1020 Cl atoms • 1.81 x 1024 Cl atoms • 9.58 x 1020 Cl atoms Calculate the molar mass of (NH4)2SO4 • 114.11 g/mol • 228.22 g/mol • 132.15 g/mol • 118.14 g/mol 2. Calculate the mass of 4.50 moles of Ca3PO4 • 215 g • 968 g • 87.1 g • 392 g 3. The mineral pyrolusite is a compound of 55Mn and 16O. If 63% of the mass of pyrolusite is due to manganese, what is the empirical formula of pyrolusite? • MnO • Mn2O • Mn2O2 • MnO2 4. A compound with an empirical formula of C2H4Br has a molar mass of 215.90 g/mol. What is the molecular formula? • C4H8Br2 • C2H4Br • CHBr • C6H12Br3 5. An unknown compound with a molar mass of 155.06 g/mol consists of 46.47% C, 7.80% H, and 45.72% Cl. Find the molecular formula for the compound. • CHCl • C9H18Cl3 • C6H12Cl • C6H12Cl2 6. Which one of the following is an example of a balanced chemical reaction? • HCl + KMnO4 → Cl2 + MnO2 + 2H2O + KCl • 2HCl + 2KMnO4 → Cl2 + MnO2 + 2H2O + 2KCl • 6HCl + 2KMnO4 → 2Cl2 + 2MnO2 + 4H2O + 2KCl • 8HCl + 2KMnO4 → 3Cl2 + 2MnO2 + 4H2O + 2KCl 7. How many atoms are in one mole of CH3OH? • 6 • 6.0 x 1023 • 12.0 x 1023 • 3.6 x