Which of the following values gives the number of parts per million (ppm) of NaCl in a 0.90% saline solution?

Question

Which of the following values gives the number of parts per million (ppm) of NaCl in a 0.90% saline solution?

Quizplus · Accepted Answer

11ecba2d_11f6_46da_a3bf_b7a2fe537075_MD0008_00 Similar to the concept of a percent (a fraction out of a basis of 100), parts per million (ppm) is a fraction out of a basis of 1,000,000. For example, 1 ppm means 1 unit in 1,000,000 units. 11ecba2d_11f6_46db_a3bf_9126c1a02388_MD0008_00 Because the units involved in the fraction are the same (or can be converted to an equivalent by a conversion factor), the units cancel out and ppm (like percent) becomes a dimensionless quantity. A fraction correctly expresses ppm as long as the numerator is one million times smaller than the denominator. For solutions, the density of water (1 g/mL) can be used to relate the mass of water to its volume. Accordingly, 1 L (1,000 mL) of water has a mass of 1 kg (1,000 g). This relationship shows that 1 ppm in an aqueous solution is equivalent to 1 mg/L. 11ecba2d_11f6_46dc_a3bf_f7e827215f90_MD0008_00 The relationship between percent and ppm is a matter of scale because the basis for ppm is 10,000 times larger than the basis for percent (1,000,000 ÷ 100 = 10,000). As a result 1% = 10,000 ppm. Using this equality as a conversion factor, the equivalent ppm concentration for the 0.90% aqueous NaCl solution can be determined by multiplying the percentage by the conversion factor: 0.90% × 10,000 ppm/percent = 9,000 ppm. Alternately, the conversion can be performed more rigorously by setting up an equation involving equivalent ratios and solving for the unknown quantity in the ppm ratio: 11ecba2d_11f6_46dd_a3bf_eb8488021079_MD0008_00 11ecba2d_11f6_46de_a3bf_396b6a0e63a7_MD0008_00 11ecba2d_11f6_6def_a3bf_63379668a449_MD0008_00 11ecba2d_11f6_6df0_a3bf_3f43d1182458_MD0008_00 Therefore, a 0.90% NaCl solution is equivalent to a concentration of 9,000 ppm. (Choice A) A value of 900 is the equivalent concentration in parts per one hundred thousand, not parts per million. (Choice C) A value of 90,000 is the equivalent concentration in parts per ten million, not parts per million. (Choice D) A value of 900,000 is the equivalent concentration in parts per one hundred million, not parts per million. Educational objective: Parts per million (ppm) is a dimensionless quantity used to express concentrations as a fraction out of a basis of 1,000,000. In aqueous solutions, 1 ppm = 1 mg/L, and for concentrations expressed as a percentage, 1% = 10,000 ppm.

Which of the Following Values Gives the Number of Parts