3.3 Molarity  (Page 5/14)

What does it mean when we say that 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 CoCl ₂ in 0.654 L of solution

(b) 98.0 g of phosphoric acid, H ₃ PO ₄ , in 1.00 L of solution

(c) 0.2074 g of calcium hydroxide, Ca(OH) ₂ , in 40.00 mL of solution

(d) 10.5 kg of Na ₂ SO ₄ ·10H ₂ O in 18.60 L of solution

(e) 7.0 $\times$ 10 ⁻³ mol of I ₂ in 100.0 mL of solution

(f) 1.8 $\times$ 10 ⁴ mg of HCl in 0.075 L of solution

Determine the molarity of each of the following solutions:

(a) 1.457 mol KCl in 1.500 L of solution

(b) 0.515 g of H ₂ SO ₄ in 1.00 L of solution

(c) 20.54 g of Al(NO ₃ ) ₃ in 1575 mL of solution

(d) 2.76 kg of CuSO ₄ ·5H ₂ O in 1.45 L of solution

(e) 0.005653 mol of Br ₂ in 10.00 mL of solution

(f) 0.000889 g of glycine, C ₂ H ₅ NO ₂ , in 1.05 mL of solution

Consider this question: What is the mass of the solute in 0.500 L of 0.30 M glucose, C ₆ H ₁₂ 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) 2.00 L of 18.5 M H ₂ SO ₄ , concentrated sulfuric acid

(b) 100.0 mL of 3.8 $\times$ 10 ⁻⁵ M NaCN, the minimum lethal concentration of sodium cyanide in blood serum

(c) 5.50 L of 13.3 M H ₂ CO, the formaldehyde used to “fix” tissue samples

(d) 325 mL of 1.8 $\times$ 10 ⁻⁶ M FeSO ₄ , the minimum concentration of iron sulfate detectable by taste in drinking water

Calculate the number of moles and the mass of the solute in each of the following solutions:

(a) 325 mL of 8.23 $\times$ 10 ⁻⁵ M KI, a source of iodine in the diet

(b) 75.0 mL of 2.2 $\times$ 10 ⁻⁵ M H ₂ 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 L of 3.716 M (NH ₄ ) ₂ SO ₄ , a liquid fertilizer

Consider this question: What is the molarity of KMnO ₄ in a solution of 0.0908 g of KMnO ₄ in 0.500 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, C ₂₇ H ₄₆ O, in 0.100 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 H ₇ OH, in 2.50 L of solution, the concentration of isopropyl alcohol in rubbing alcohol

(d) 0.029 g of I ₂ in 0.100 L of solution, the solubility of I ₂ in water at 20 °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 g FeCl ₃ in 0.1250 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 g C ₇ H ₅ SNO ₃ in one ounce (29.6 mL), the concentration of saccharin in a diet soft drink.

There is about 1.0 g of calcium, as Ca ²⁺ , in 1.0 L of milk. What is the molarity of Ca ²⁺ in milk?

What volume of a 1.00- M Fe(NO ₃ ) ₃ solution can be diluted to prepare 1.00 L of a solution with a concentration of 0.250 M ?

If 0.1718 L of a 0.3556- M C ₃ 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 -H ₃ PO ₄ solution is be diluted to a volume of 10.00 L, what is the concentration of the resulting solution?

What volume of a 0.33- M C ₁₂ H ₂₂ O ₁₁ solution can be diluted to prepare 25 mL of a solution with a concentration of 0.025 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 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 L of a 0.250- M solution of Fe(NO ₃ ) ₃ is diluted to a final volume of 2.00 L

(b) 0.5000 L of a 0.1222- M solution of C ₃ H ₇ OH is diluted to a final volume of 1.250 L

(c) 2.35 L of a 0.350- M solution of H ₃ PO ₄ is diluted to a final volume of 4.00 L

(d) 22.50 mL of a 0.025- M solution of C ₁₂ H ₂₂ O ₁₁ is diluted to 100.0 mL

What is the final concentration of the solution produced when 225.5 mL of a 0.09988- M solution of Na ₂ CO ₃ is allowed to evaporate until the solution volume is reduced to 45.00 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?

What volume of a 0.20- M K ₂ SO ₄ solution contains 57 g of K ₂ SO ₄ ?

The US Environmental Protection Agency (EPA) places limits on the quantities of toxic substances that may be discharged into the sewer system. Limits have been established for a variety of substances, including hexavalent chromium, which is limited to 0.50 mg/L. If an industry is discharging hexavalent chromium as potassium dichromate (K ₂ Cr ₂ O ₇ ), what is the maximum permissible molarity of that substance?