Parts per Million (ppm) Practice Problems

Air is enclosed in a container and exerts a total pressure of 2 atm. Find the concentration of carbon dioxide in parts per million if its partial pressure is 2.7×10^-4 atm, assuming that the average molar mass of air is 29 g/mol.

Describe the preparation of a 250 mL 102 ppm solution of salicylic acid in water

Swimming pools are treated with chlorine to kill germs. What mass of calcium chloride (CaCl₂) must be added to 900 L of water in order to create a solution containing 4.00 ppm chloride ion?

Determine which has the higher molarity in water, 30 ppm NaCl or 40000 ppb NaF.

The maximum allowable limit for cadmium is 0.2 ppb/day. The spectrophotometric quantitation of cadmium in drinking water can be performed using a complexation reaction. Cadmium(II) (Cd²⁺) makes a deep greenish-yellow complex (1:1 mole ratio) with alizarin red S. The extinction coefficient of the complex is 2.24×10³ L•mol⁻¹•cm⁻¹ at 422 nm. Given that most spectrophotometers cannot detect absorbances less than 0.0001 with good reliability, is this method a good way to quantify cadmium at its allowable limit in drinking water? Assume a cell path length of 1.0 cm.

Arsenic and all its inorganic compounds are highly toxic substances. A blood concentration of more than 5 μg/dL of arsenic is harmful to human health. A study performed on a small number of people working in the alloy industry found an average concentration of 8.5 μg/dL. Express this concentration in ppm units.

The maximum allowable amount of nitrate, measured as nitrogen, in drinking water is 10.0 ppm (by mass). Calculate the correponding molarity of the nitrate ion.

The US EPA's regulatory limit for mercury (Hg) in drinking water is 2.0 ppb. A 255 L water sample was acquired from a lake and found to contain 2.3 ppb of Hg. How many grams of mercury are there in the water sample?

A concentration of 4.00  ppm of chlorine is considered to be safe drinking water. How much water must a person consume in order to intake 1.0 g of chlorine?

WHO guidelines recommend that the amount of residual chlorine in drinking water should not be higher than 5 parts per million (ppm). The amount of chlorine can be determined by back titration with potassium iodide:
Cl₂(aq) + 2 I⁻(aq) → 2 Cl⁻(aq) + I₂(aq)
The iodine formed as a result of the reaction above is then titrated with a solution of sodium thiosulfate:
2 Na₂S₂O₃(aq) + I₂(aq) → 2 NaI(aq) + Na₂S₄O₆(aq)
A 385.0 mL water sample was added with excess solid sodium iodide and the resulting solution was then titrated against a 1.88×10⁻³ M sodium thiosulphate solution. The solution required 12.7 mL of Na₂S₂O₃ to reach the equivalence point. Calculate the concentration of chlorine in the water sample in ppm units.

WHO guidelines recommend that the amount of residual chlorine in drinking water should not be higher than 5 parts per million (ppm). The amount of chlorine can be determined by back titration with potassium iodide:
Cl₂(aq) + 2 I⁻(aq) → 2 Cl⁻(aq) + I₂(aq)
The iodine formed as a result of the reaction above is then titrated with a solution of sodium thiosulfate:
2 Na₂S₂O₃(aq) + I₂(aq) → 2 NaI(aq) + Na₂S₄O₆(aq)
A 350.0 mL water sample was added with excess solid sodium iodide and the resulting solution was then titrated against a 2.25×10⁻³ M sodium thiosulphate solution. The solution required 14.5 mL of Na₂S₂O₃ to reach the equivalence point. How many grams of chlorine are there in the water sample?

What is the concentration of mercury in ppm if there are 321.4 μg mercury ions in a 4.50 L of water?