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- The following pictures represent equilibrium mixtures at 325 K and 350 K for a reaction involving A atoms (red), B atoms (blue), and AB molecules. (a) Write a balanced equation for the reaction that occurs on raising the temperature.
Problem 47
Problem 47a
What are the molecular weights of the following herbicides? (a) C6H6Cl2O3 (2, 4-dichlorophenoxyacetic acid, effective on broadleaf plants)
Problem 47b
What are the molecular weights of the following herbicides? (b) C15H22ClNO2 (metolachlor, pre-emergent herbicide)
Problem 47c
What are the molecular weights of the following herbicides? (c) C8H6Cl2O3 (dicamba, effective on broadleaf plants
Problem 48a
How many grams are in a mole of each of the following substances? (a) Ti
Problem 48b
How many grams are in a mole of each of the following substances? (b) Br2
Problem 48c
How many grams are in a mole of each of the following substances? (c) Hg
Problem 48d
How many grams are in a mole of each of the following substances? (d) H2O
Problem 50
How many moles of ions are in 27.5 g of MgCl2
Problem 51
How many moles of anions are in 35.6 g of AlF3?
Problem 52
What is the molecular weight of chloroform if 0.0275 mol weighs 3.28 g?
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