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Problem 53
What is the molecular weight of cholesterol if 0.5731 mol weighs 221.6 g?
Problem 54
Iron(II) sulfate, FeSO4, is prescribed for the treatment of anemia. How many moles of FeSO4 are present in a standard 300 mg tablet? How many iron(II) ions?
Problem 55
The 'lead' in lead pencils is actually almost pure carbon, and the mass of a period mark made by a lead pencil is about 0.0001 g. How many carbon atoms are in the period?
Problem 56
An average cup of coffee contains about 125 mg of caffeine, C8H10N4O2. How many moles of caffeine are in a cup? How many molecules of caffeine?
Problem 57a
What is the mass in grams of each of the following samples? (a) 0.0015 mol of sodium
Problem 57b
What is the mass in grams of each of the following samples? (b) 0.0015 mol of lead
Problem 57c
What is the mass in grams of each of the following samples? (c) 0.0015 mol of diazepam (Valium), C16H13ClN2O
Problem 58a
A sample that weighs 25.12 g contains 6.022⨉1023 particles. If 25.00% of the total number of particles are argon atoms and 75.00% are another element, what is the chemical identity of the other constituent?
Problem 59
A sample that weighs 107.75 g is a mixture of 30% helium atoms and 70% krypton atoms. How many particles are present in the sample?
Problem 60
Titanium metal is obtained from the mineral rutile, TiO2. How many kilograms of rutile are needed to produce 100.0 kg of Ti?
- Iron metal can be produced from the mineral hematite, Fe2O3, by reaction with carbon. How many kilograms of iron are present in 105 kg of hematite?
Problem 61
- In the preparation of iron from hematite, Fe2O3 reacts with carbon: Fe2O3 + C --> Fe + CO2 Unbalanced (a) Balance the equation. (b) How many moles of carbon are needed to react with 525 g of hematite? (c) How many grams of carbon are needed to react with 525 g of hematite?
Problem 62
- An alternative method for preparing pure iron from Fe2O3 is by reaction with carbon monoxide: Fe2O3 + CO --> Fe + CO2 Unbalanced. (a) Balance the equation. (b) How many grams of CO are needed to react with 3.02 g of Fe2O3? (c) How many grams of CO are needed to react with 1.68 mol of Fe2O3?
Problem 63
Problem 64a
Magnesium metal burns in oxygen to form magnesium oxide, MgO. (a) Write a balanced equation for the reaction.
Problem 64b
Magnesium metal burns in oxygen to form magnesium oxide, MgO. (b) How many grams of oxygen are needed to react with 25.0 g of Mg? How many grams of MgO will result?
Problem 64c
Magnesium metal burns in oxygen to form magnesium oxide, MgO. (c) How many grams of Mg are needed to react with 25.0 g of O2? How many grams of MgO will result?
- Ethylene gas, C2H4, reacts with water at high temperature to yield ethyl alcohol, C2H6O. (a) How many grams of ethylene are needed to react with 0.133 mol of H2O? How many grams of ethyl alcohol will result? (b) How many grams of water are needed to react with 0.371 mol of ethylene? How many grams of ethyl alcohol will result?
Problem 65
- Pure oxygen was first made by heating mercury(II) oxide: HgO --> (heat) Hg + O2 Unbalanced (a) Balance the equation. (b) How many grams of mercury and how many grams of oxygen are formed from 45.5 g of HgO? (c) How many grams of HgO would you need to obtain 33.3 g of O2
Problem 66
- Titanium dioxide (TiO2), the substance used as the pigment in white paint, is prepared industrially by reaction of TiCl4 with O2 at high temperature. TiCl4 + O2 --> (heat) TiO2 + 2 Cl2 How many kilograms of TiO2 can be prepared from 5.60 kg of TiCl4?
Problem 67
- Silver metal reacts with chlorine (Cl2) to yield silver chlo-ride. If 2.00 g of Ag reacts with 0.657 g of Cl2, what is the empirical formula of silver chloride?
Problem 68
- Aluminum reacts with oxygen to yield aluminum oxide. If 5.0 g of Al reacts with 4.45 g of O2, what is the empirical formula of aluminum oxide?
Problem 69
- The industrial production of hydriodic acid takes place by treatment of iodine with hydrazine (N2H4): 2 I2 + N2H4 --> 4 HI + N2 (b) How many grams of HI are produced from the reaction of 115.7 g of N2H4 with excess iodine
Problem 70
Problem 71a
An alternative method for producing hydriodic acid is the reaction of iodine with hydrogen sulfide: H2S + I2 → 2 HI + S (a) How many grams of I2 are needed to react with 49.2 g of H2S?
Problem 71b
An alternative method for producing hydriodic acid is the reaction of iodine with hydrogen sulfide:H2S + I2 → 2 HI + S (b) How many grams of HI are produced from the reaction of 95.4 g of H2S with excess I2?
Problem 72a
Nickel(II) sulfate, used for nickel plating, is prepared by treat-ment of nickel(II) carbonate with sulfuric acid: NiCO3 + H2SO4 → NiSO4 + CO2 + H2O (a) How many grams of H2SO4 are needed to react with 14.5 g of NiCO3?
Problem 72b
Nickel(II) sulfate, used for nickel plating, is prepared by treat-ment of nickel(II) carbonate with sulfuric acid: NiCO3 + H2SO4 → NiSO4 + CO2 + H2O
(b) How many grams of NiSO4 are obtained if the yield is 78.9%?
Problem 73a
Hydrazine, N2H4, once used as a rocket propellant, reacts with oxygen: N2H4 + O2 → N2 + 2 H2O (a) How many grams of O2 are needed to react with 50.0 g of N2H4?
Problem 73b
Hydrazine, N2H4, once used as a rocket propellant, reacts with oxygen: N2H4 + O2 → N2 + 2 H2O (b) How many grams of N2 are obtained if the yield is 85.5%?
- Assume that you have 1.39 mol of H2 and 3.44 mol of N2. How many grams of ammonia (NH3) can you make, and how many grams of which reactant will be left over? 3 H2 + N2 --> NH3
Problem 74
- Hydrogen and chlorine react to yield hydrogen chloride: H2 + Cl2 ¡ 2 HCl. How many grams of HCl are formed from reaction of 3.56 g of H2 with 8.94 g of Cl2? Which reactant is limiting?
Problem 75