A 3.2-gram sample of air contains 0.000 74 gram of hydrogen cyanide. Determine the concentration, in parts per million, of the hydrogen cyanide in this sample.

The answer is: 231.25 ppm.

To solve this, compute first the percentage of hydrogen in the 3.2 g air sample. % = (0.00074g/3.2g) * 100 = 0.023125%

1% = 10,000ppm < - - - use this as conversion factor.

0.023125% (10,000ppm/1%) = 231.25 ppm