Unit 1 – ppm
Unit 1 - Jan 2009
Q1.
Another halogenoalkane, bromomethane, CH3Br, is a toxic gas used to protect plants against insects.  Health and Safety advice states that concentrations above 5 parts per million (ppm) by volume of this gas are harmful.
A research laboratory contains 2.5 × 105 dm3 of air.  Calculate the maximum volume of bromomethane, in dm3, allowed in the laboratory to comply with the advice given.
(1)

Unit 1 - Jan 2010
Q2.
(e) Blood plasma typically contains 20 parts per million (ppm) of magnesium, by mass.
(i) Calculate the mass of magnesium, in grams, present in 100 g of plasma.
(1)

Unit 1 – Jun 2010
Q3.
(iii) 1 kg of a solution contains 0.100 mol of calcium ions, Ca2+.  What is the concentration of the calcium ions by mass in parts per million (ppm)? [Assume the relative atomic mass of calcium is 40.]
(2)

.....................................ppm
Unit 1 - Jun 2013
Q4.
A sample of swimming pool water contains 0.482 parts per million (ppm) of chlorine. This is equal to a percentage of
   A    0.000482
   B    0.0000482
   C    0.00000482
   D    0.000000482

Unit 1 - Jun 2014
Q5.
The recommended limit for safe exposure to sulfur dioxide in the air is 0.000025%. 
What is this concentration in parts per million, ppm?
   A    25
   B    0.25
   C    0.025
   D    0.0025

Answers
Q1

Q2

Q3

Q4

Q5