CHM Ch.7
(7.5) Calculate the molar mass of C2H6O.
1 mole C2H6O = 46.08 g
(7.5) Calculate the molar mass for lithium carbonate, Li2CO3, used to treat bipolar disorder.
1 mole Li2CO3 = 73.89 g
(7.7) Consider the following equation: 3H2(g) + N2(g) → 2NH3(g) 1. A mole-mole factor for H2 and N2 is 2. A mole-mole factor for NH3 and H2 is
1. 1 mole N2/3 moles H2 2. 2 moles NH3/ 3 moles H2
(7.1) Balance and list the coefficients in order from reactants to products. 1. __Fe2O3(s) + __C(s) → __Fe(s) + __CO2(g) A. 2, 3, 2, 3 B. 2, 3, 4, 3 C. 1, 1, 2, 3 2. __Al(s) + __FeO(s) → __Fe(s) + __Al2O3(s) A. 2, 3, 3, 1 B. 2, 1, 1, 1 C. 3, 3, 3, 1 3. __Al(s) + __H2SO4(aq) → __Al2(SO4)3(aq) + __H2(g) A. 3, 2, 1, 2 B. 2, 3, 1, 3 C. 2, 3, 2, 3
1. B 2. A 3. B
(7.1) Balance each of the following chemical equations: 1. Mg(s)+AgNO3(aq) → (NO3)2(aq)+Ag(s) 2. Al(s)+CuSO4(aq) → Al2(SO4)3(aq)+Cu(s) 3. Pb(NO3)2(aq)+NaCl(aq) → PbCl2(s)+NaNO3(aq) 4. HCl(aq)+Al(s) → H2(g)+AlCl3(aq)
1. Mg(s)+2AgNO3(aq) → Mg(NO3)2(aq)+2Ag(s) 2. 2Al(s)+3CuSO4(aq) → Al2(SO4)3(aq)+3Cu(s) 3. Pb(NO3)2(aq)+2NaCl(aq) → PbCl2(s)+2NaNO3(aq) 4. 6HCl(aq)+2Al(s) → 3H2(g)+2AlCl3(aq)
(7.2) Each of the following reactions and balance: 1. combination: Mg(s)+Cl2(g) → 2. decomposition: HBr(g) → 3. single replacement: Mg(s)+Zn(NO3)2(aq) → 4. double replacement: K2S(aq)+Pb(NO3)2(aq) → 5. combustion: C2H6(g)+O2(g) →
1. MgCl2(s) 2. H2(g)+Br2(l) 3. Zn(s)+Mg(NO3)2(aq) 4. PbS(s)+2KNO3(aq) 5. 4CO2(g)+6H2O(g)
(7.3) Identify each of the following as oxidation or reduction: A. Sn(s) → Sn4+(aq) + 4e− B. Fe3+(aq) + 1e− → Fe2+(aq) C. Cl2(g) + 2e− → 2Cl− (aq)
1. Oxidation 2. Reduction 3. Reduction
(7.2) Identify each reaction as a combination, decomposition, combustion, single replacement, or double replacement. 1. 3Ba(s) + N2(g) → Ba3N2(s) 2. 2Ag(s) + H2S(aq) → Ag2S(s) + H2(g) 3. 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) 4. PbCl2(aq) + K2SO4(aq) → 2KCl(aq) + PbSO4(s) 5. K2CO3(s) → K2O(aq) + CO2(g)
1. combination 2. single replacement 3. combustion 4. double replacement 5. decomposition
(7.1) Determine whether each of the following chemical equations is balanced or not balanced: 1. S(s)+O2(g) → SO3(g) 2. 2Ga(s)+3Cl2(g) → 2GaCl3(s) 3. H2(g)+O2(g) → H2O(g) 4. C3H8(g)+5O2(g) → 3CO2(g)+4H2O(g)
1. not balanced 2. balanced 3. not balanced 4. balanced
(7.4) How many molecules are present in 1.75 moles of carbon dioxide, CO2?
1.05 x 1024 molecules of CO2
(7.6) A salt shaker contains 73.7 g of NaCl. How many moles of NaCl are present?
1.26 moles of NaCl
(7.8) The reaction between H2 and O2 produces 13.1 g of water. How many grams of O2 reacted? 2H2(g) + O2(g) → 2H2O(g)
11.6g of O2
(7.4) The number of moles of S in 1.8 × 1024 atoms of S is 1. 1.0 mole of S atoms. 2. 3.0 moles of S atoms. 3. 1.1 × 1048 moles of S atoms.
2
(7.8) How many grams of O2 are needed to produce 45.8 grams of Fe2O3 in the following reaction? 4Fe(s) + 3O2(g) → 2Fe2O3(s) 1. 38.4 g of O2 2. 13.8 g of O2 3. 1.38 g of O2
2
(7.4) The number of atoms in 2.0 moles of Al is 1. 2.0 Al atoms. 2. 3.0 × 1023 Al atoms. 3. 1.2 × 1024 Al atoms.
3
(7.7) How many moles of Fe are needed for the reaction of 12.0 moles of O2? 4Fe(s) + 3O2(g) → 2Fe2O3(s) 1. 3.00 moles of Fe 2. 9.00 moles of Fe 3. 16.0 moles of Fe
3
(7.7) How many moles of Fe are needed for the reaction of 12.0 moles of O2? 4Fe(s) + 3O2(g) → 2Fe2O3(s) 1. 3.00 moles of Fe 2. 9.00 moles of Fe 3. 16.0 moles of Fe
3
(7.6) A sample of water has a mass of 59.8 grams. How many moles of water are in the sample?
3.32 moles H2O
(7.4) How many atoms of O are in 0.150 mole of aspirin, C9H8O4?
3.61 × 1023 atoms of O
(7.7) How many moles of Fe2O3 can form from 6.0 moles of O2? 4Fe(s) + 3O2(g) → 2Fe2O3(s)
4.0 moles Fe2O3
