Chemical Composition Stoichiometry Review

How many moles of Ca are 3.01  1023 atoms of calcium? 6.1 3.01 mol 1.81  1047 mol 1.00 mol 0.500 mol 3.01  1023 mol Answer: d

How many grams are in 1.000 mol of iron? 6.3 1.000 g 6.022  1023 g 0.01791 g 26.00 g 55.85 g Answer: e

What is the molar mass of ammonium nitrate? 6.4 112.12 g/mol 80.05 g/mol 66.04 g/mol 114.00 g/mol 95.23 g/mol Answer: b

What is the mass of 4.55  1023 copper atoms? 6.6 4.55 g 4.31  1045 g 1.18  10–2 g 6.02  1023 g 48.0 g Answer: e

How many moles are in 5.672 g of iron(III) sulfate? 6.7 3.730  10–2 mol 2.268  10–3 mol 2.268  103 mol 5.672  10–3 mol 1.418  10–2 mol Answer: e

How many moles are in 5.6 g of lithium nitride? 6.9 0.27 mol 0.20 mol 0.16 mol 0.56 mol 2.0  102 mol Answer: c

How many moles of oxygen are in 3.45 mol of diphosphorus pentoxide? 6.11 6.90 mol O 3.45 mol O 5.75 mol O 13.5 mol O 17.3 mol O Answer: e

What is the mass of 5.660 mol of dinitrogen tetrahydride? 6.14 90.70 g 0.1765 g 5.66 g 181.4 g 0.353 g Answer: d

An unknown compound has a molar mass of 118. 10 g/mol An unknown compound has a molar mass of 118.10 g/mol. Given the following mass percent composition, calculate the empirical and molecular formulas: 40.7% C, 5.13% H, and 54.2% O. 6.19 CH1.5O and C2H3O2 C3H5O3 and C6H10O6 C4H6O4 and C8H12O8 C4H6O4 and C2H3O2 C2H3O2 and C4H6O4 Answer: e

What is the empirical formula of ascorbic acid, C6H8O6, a compound found in citrus fruits? 6.22 C6H8O6 C4H4O4 C3H4O3 CHO CH2O Answer: c

Identify the diatomic molecule that has a mass of 33 Identify the diatomic molecule that has a mass of 33.86 g and contains 0.891 moles of molecules. 6.23 H2 N2 O2 F2 Cl2 Answer: d

Calculate the empirical formula of a 5 Calculate the empirical formula of a 5.85 g sample of an unknown chromium oxide containing 4.00 g of chromium. 6.24 Cr2O7 Cr2O4 CrO CrO1.5 Cr2O3 Answer: e

What is the empirical formula of a compound that contains 14 What is the empirical formula of a compound that contains 14.5% hydrogen and 85.5% carbon by mass? 6.25 CH CH2 C2H C2H3 CH3 Answer: b

What is the mass percentage of oxygen in glycerol, C3H8O3? 6.26 6.25% 26.08% 54% 52.12% 64.32% Answer: b

The empirical formula of a compound is found to be CH2O The empirical formula of a compound is found to be CH2O. If its molar mass is 180.2 g/mol, what is the molecular formula of the compound? 6.27 CH2O C3H6O3 C6H12O6 C2H4O2 None of the above Answer: c

A variety of Freon contains 69. 58% chlorine by mass A variety of Freon contains 69.58% chlorine by mass. How many grams of chlorine are contained in 11.3 g of this substance? 6.28 7.86 g 5.35 g 7.863 g 0.1624 g None of the above Answer: a

What is the mass percentage of oxygen in potassium chlorate? 6.29 6.527% 13.06% 19.60% 39.17% None of the above Answer: d

A compound is found to contain 60. 00% C, 4. 48% H and 35. 53% O A compound is found to contain 60.00% C, 4.48% H and 35.53% O. What is its empirical formula? 6.30 C9H8O4 C3H2O C2H2O2 C2H2O None of the above Answer: a