Water contains 9 ppm dissolved oxygen. What is the approximate mass of oxygen in 500 mL water?
Answer and explanation
Correct answer: 4.5 mg
For a dilute aqueous solution, 9 ppm is approximately 9 mg of dissolved oxygen per litre of water. Convert the volume: 500 mL = 0.500 L. Therefore, oxygen mass = 9 mg L−1 × 0.500 L = 4.5 mg. Option B is correct. Option A results from an incorrect factor, while 9.0 mg would correspond to 1 L; option D doubles the correct value.
Frequently asked questions
What is the correct answer to this question?
4.5 mg
Why is this the correct answer?
For a dilute aqueous solution, 9 ppm is approximately 9 mg of dissolved oxygen per litre of water. Convert the volume: 500 mL = 0.500 L. Therefore, oxygen mass = 9 mg L−1 × 0.500 L = 4.5 mg. Option B is correct. Option A results from an incorrect factor, while 9.0 mg would correspond to 1 L; option D doubles the correct value.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Chapter 01: Solutions.
