Chapter 6

What is the total mass (amu) of carbon in each of the following molecules? (a) \(\mathrm{CH}_{4}\) (b) \(\mathrm{CHCl}_{3}\) (c) \(\mathrm{C}_{12} \mathrm{H}_{10} \mathrm{O}_{6}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}\)

Calculate the molecular or formula mass of each of the following: (a) \(\mathrm{P}_{4}\) (b) \(\mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}\) (acetic acid) (e) \(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\) (sucrose, cane sugar)

Determine the empirical formulas for compounds with the following percent compositions: (a) 15.8\% carbon and 84.2\% sulfur (b) 40.0\% carbon, 6.7\% hydrogen, and 53.3\% oxygen

Determine the empirical formulas for compounds with the following percent compositions: (a) 43.6\% phosphorus and 56.4\% oxygen (b) 28.7\% K, 1.5\% H, 22.8\% P, and 47.0\% O

Determine the empirical and molecular formula for chrysotile asbestos. Chrysotile has the following percent composition: 28.03\% Mg, 21.60\% Si, 1.16\% H, and 49.21\% O. The molar mass for chrysotile is 520.8 g/mol.

Polymers are large molecules composed of simple units repeated many times. Thus, they often have relatively simple empirical formulas. Calculate the empirical formulas of the following polymers: (a) Lucite (Plexiglas); 59.9\% C, 8.06\% H, 32.0\% O (b) Saran; 24.8\% C, 2.0\% H, 73.1\% Cl (c) polyethylene; \(86 \%\) C \(, 14 \%\) H (d) polystyrene; \(92.3 \%\) C \(, 7.7 \% \mathrm{H}\) (e) Orlon; \(67.9 \%\) C, \(5.70 \%\) H, \(26.4 \%\) N

Explain what changes and what stays the same when \(1.00 \mathrm{L}\) of a solution of \(\mathrm{NaCl}\) is diluted to \(1.80 \mathrm{L}\).

A 200-mL sample and a 400-mL sample of a solution of salt have the same molarity. In what ways are the two samples identical? In what ways are these two samples different?

Determine the molarity for each of the following solutions: (a) 0.444 mol of \(\mathrm{CoCl}_{2}\) in 0.654 L of solution. (b) \(98.0 \mathrm{g}\) of phosphoric acid, \(\mathrm{H}_{3} \mathrm{PO}_{4},\) in \(1.00 \mathrm{L}\) of solution. (c) \(0.2074 \mathrm{g}\) of calcium hydroxide, \(\mathrm{Ca}(\mathrm{OH})_{2},\) in \(40.00 \mathrm{mL}\) of solution. (d) \(10.5 \mathrm{kg}\) of \(\mathrm{Na}_{2} \mathrm{SO}_{4} \cdot 10 \mathrm{H}_{2} \mathrm{O}\) in \(18.60 \mathrm{L}\) of solution. (e) \(7.0 \times 10^{-3}\) mol of \(I_{2}\) in \(100.0 \mathrm{mL}\) of solution. (f) \(1.8 \times 10^{4} \mathrm{mg}\) of \(\mathrm{HCl}\) in \(0.075 \mathrm{L}\) of solution.

Consider this question: What is the mass of the solute in 0.500 L of 0.30 M glucose, \(C_{6} \mathrm{H}_{12} \mathrm{O}_{6}\), used for intravenous injection? (a) Outline the steps necessary to answer the question. (b) Answer the question.

Consider this question: What is the mass of solute in 200.0 L of a 1.556-M solution of KBr? (a) Outline the steps necessary to answer the question. (b) Answer the question.

Calculate the number of moles and the mass of the solute in each of the following solutions: (a) \(325 \mathrm{mL}\) of \(8.23 \times 10^{-5} \mathrm{M} \mathrm{KI}\), a source of iodine in the diet. (b) 75.0 mL of 2.2 \(\times 10^{-5} \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}\), a sample of acid rain. (c) 0.2500 L of 0.1135 \(M\) K \(_{2}\) CrO \(_{4}\), an analytical reagent used in iron assays. (d) \(10.5 \mathrm{L}\) of \(3.716 M\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4},\) a liquid fertilizer.

Consider this question: What is the molarity of \(\mathrm{KMnO}_{4}\) in a solution of \(0.0908 \mathrm{g}\) of \(\mathrm{KMnO}_{4}\) in \(0.500 \mathrm{L}\) of solution? (a) Outline the steps necessary to answer the question. (b) Answer the question.

Consider this question: What is the molarity of HCl if 35.23 mL of a solution of HCl contain 0.3366 g of HCl? (a) Outline the steps necessary to answer the question. (b) Answer the question.

Calculate the molarity of each of the following solutions: (a) 0.195 g of cholesterol, \(\mathrm{C}_{27} \mathrm{H}_{46} \mathrm{O}\), in 0.100 \(\mathrm{L}\) of serum, the average concentration of cholesterol in human serum. (b) 4.25 g of NH 3 in 0.500 L of solution, the concentration of NH 3 in household ammonia. (c) 1.49 kg of isopropyl alcohol, C \(_{3} \mathrm{H}_{7} \mathrm{OH}\), in 2.50 \(\mathrm{L}\) of solution, the concentration of isopropyl alcohol in rubbing alcohol. (d) 0.029 g of I_ in 0.100 L of solution, the solubility of I \(_{2}\) in water at \(20^{\circ} \mathrm{C}\).

Calculate the molarity of each of the following solutions: (a) 293 g HCl in 666 mL of solution, a concentrated HCl solution/ (b) \(2.026 \mathrm{g} \mathrm{FeCl}_{3}\) in \(0.1250 \mathrm{L}\) of a solution used as an unknown in general chemistry laboratories/ (c) 0.001 mg Cd 2+ in 0.100 L, the maximum permissible concentration of cadmium in drinking water. (d) \(0.0079 \mathrm{g} \mathrm{C}_{7} \mathrm{H}_{5} \mathrm{SNO}_{3}\) in one ounce \((29.6 \mathrm{mL}),\) the concentration of saccharin in a diet soft drink.

There is about \(1.0 \mathrm{g}\) of calcium, as \(\mathrm{Ca}^{2+},\) in \(1.0 \mathrm{L}\) of milk. What is the molarity of \(\mathrm{Ca}^{2+}\) in milk?

What volume of a \(1.00-M \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}\) solution can be diluted to prepare \(1.00 \mathrm{L}\) of a solution with a concentration of \(0.250 \mathrm{M} ?\)

If 0.1718 L of a \(0.3556-M C_{3} \mathrm{H}_{7}\) OH solution is diluted to a concentration of \(0.1222 M,\) what is the volume of the resulting solution?

If 4.12 L of a 0.850 \(M-\mathrm{H}_{3} \mathrm{PO}_{4}\) solution is be diluted to a volume of 10.00 \(\mathrm{L},\) what is the concentration of the resulting solution?

What volume of a 0.33- \(M\) C \(_{12} \mathrm{H}_{22} \mathrm{O}_{11}\) solution can be diluted to prepare 25 \(\mathrm{mL}\) of a solution with a concentration of \(0.025 \mathrm{M}\) ?

What is the concentration of the NaCl solution that results when 0.150 L of a 0.556-M solution is allowed to evaporate until the volume is reduced to \(0.105 \mathrm{L}\) ?

What is the molarity of the diluted solution when each of the following solutions is diluted to the given final volume? (a) \(1.00 \mathrm{L}\) of a \(0.250-M\) solution of \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}\) is diluted to a final volume of \(2.00 \mathrm{L}\). (b) 0.5000 L of a 0.1222-M solution of C \(_{3} \mathrm{H}_{7} \mathrm{OH}\) is diluted to a final volume of 1.250 \(\mathrm{L}\). (c) 2.35 L of a 0.350-M solution of H_3Pa is diluted to a final volume of 4.00 L. (d) 22.50 mL of a 0.025-M solution of \(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\) is diluted to \(100.0 \mathrm{mL}\).

What is the final concentration of the solution produced when \(225.5 \mathrm{mL}\) of a \(0.09988-M\) solution of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) allowed to evaporate until the solution volume is reduced to \(45.00 \mathrm{mL}\) ?

A 2.00-L bottle of a solution of concentrated HCl was purchased for the general chemistry laboratory. The solution contained 868.8 g of HCl. What is the molarity of the solution?

An experiment in a general chemistry laboratory calls for a 2.00-M solution of HCl. How many mL of 11.9 M HCl would be required to make 250 mL of 2.00 M HCl?

Consider this question: What mass of a concentrated solution of nitric acid ( \(68.0 \%\) HNO \(_{3}\) by mass) is needed to prepare 400.0 g of a 10.0\% solution of HNO \(_{3}\) by mass? (a) Outline the steps necessary to answer the question. (b) Answer the question.

What mass of a \(4.00 \% \mathrm{NaOH}\) solution by mass contains \(15.0 \mathrm{g}\) of \(\mathrm{NaOH}\) ?

What mass of solid NaOH (97.0\% NaOH by mass) is required to prepare 1.00 L of a 10.0\% solution of NaOH by mass? The density of the 10.0\% solution is 1.109 g/mL.

What mass of HCl is contained in 45.0 mL of an aqueous HCl solution that has a density of \(1.19 \mathrm{g} \mathrm{cm}^{-3}\) and contains 37.21\% HCl by mass?

Copper(I) iodide (CuI) is often added to table salt as a dietary source of iodine. How many moles of CuI are contained in 1.00 lb (454 g) of table salt containing 0.0100\% Cul by mass?

D5W is a solution used as an intravenous fluid. It is a 5.0\% by mass solution of dextrose ( \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\) ) in water. If the density of D5W is \(1.029 \mathrm{g} / \mathrm{mL}\), calculate the molarity of dextrose in the solution.

Find the molarity of a 40.0\% by mass aqueous solution of sulfuric acid, \(\mathrm{H}_{2} \mathrm{SO}_{4}\), for which the density is 1.3057 \(\mathrm{g} / \mathrm{mL}\).