Exam 4: Solution Chemistry: The Hydrosphere

What mass of calcium hydroxide (molar mass = 74.1 g/mol) is produced when 15 mL of a 0.220 M solution of calcium nitrate is mixed with 25 mL of a 0.140 M solution of potassium hydroxide?

Silver salts are used in black-and-white photography. Owing to the value of silver, the ions left in developing solutions are often collected by precipitation reactions for recycling. A 4.5 L jug of a developing solution was treated with an excess of sodium chloride, and a precipitate containing 2.86 g of dry silver chloride was collected. What was the molar concentration of the silver ions in the developing solution? The net ionic equation is Ag⁺(aq) Cl^-(aq) AgCl(s)

The half-reaction for the reduction of molecular oxygen to water is ________

Magnesium metal burns brightly in the air to make a white powder. What are the likely products?

Identify the solution below that will conduct electricity the best, and explain why you picked it. (a) 1.0 M NaCl, (b) 1.2 M KCl, (c) 1.0 M Na₂SO₄, (d) 0.75 M LiCl

Sodium fluoride is added to drinking water in some municipalities to protect teeth against cavities. The target is to convert hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂, into more stable fluorapatite, Ca₁₀(PO₄)₆F₂. The U.S. Environmental Protection Agency currently restricts the concentration of fluoride in drinking water to 4 mg/L. Express this concentration in parts per million (ppm).

What is the molar concentration of sodium ions in a 0.3 M sodium phosphate (Na₃PO₄, 164 g/mol) solution? Sodium phosphate is used as a cleaning agent, food additive, and stain remover.

In which compound does chlorine have an oxidation number of +5?

The World Health Organization recommends that the maximum allowable concentration of lead(II) in drinking water be limited to 0.015 mg/L. If the absorbance of lead(II) at 417 nm is 0.289 at this concentration, what is the molar absorptivity, assuming a 10-cm-long cell was used?'

A concentrated aqueous ammonia solution has a density of 0.90 g/mL and is 28.0% ammonia by mass. Determine the molar concentration of this solution.

What is the oxidation number of P in H₂PO₄^-?

A medical saline solution is prepared by mixing 55 mg of morphine (C₁₇H₁₉NO₃) with water to make 75.0 mL of solution. What is the millimolar concentration of this solution?

Which one of the following statements regarding a weak base is not correct?

What mass of lead(II) chloride is produced when 200.0 mL of a 0.250 M solution of sodium chloride is mixed with 200.0 mL of a 0.250 M solution of lead(II) nitrate.

What mass of potassium hydroxide is needed to prepare 150 mL of a 1.30 M solution?

Assuming that the density of water is 1.00 g/mL, how many moles of water are there in a liter of water?

What mass of potassium iodide (molar mass = 166.0 g/mol) is needed to produce 325.0 mL of a solution that has a concentration of 0.0150 M ?

A food chemist determined the concentration of acetic acid in a sample of apple cider vinegar. The density of the sample was 1.01 g/mL. The volume of 1.215 M NaOH required to titrate a 25.00 mL sample of the vinegar was 19.85 mL. What is (a) the molar concentration, and (b) the percent by mass of acetic acid in this vinegar? (CH₃COOH, 60.05 g/mol)

If there are 0.505 g of NaCl left in a beaker that originally contained 75.0 mL of saltwater, what must have been the concentration of the original solution?

Sodium metal easily loses an electron to form the sodium ion. In this process, sodium is ________