Question

the dissolved oxygen concentration of a pond is 8 ppm by volume. this level of dissolved oxygen indicates that 8 ml of oxygen is found in a. 1 000 000 ml of water b. 10 000 ml of water c. 1 000 ml of water d. 100 ml of water

Explanation:

Step1: Understand ppm definition

ppm (parts per million) by volume means the volume of solute (oxygen) per \(10^6\) volumes of solution (water). So, 8 ppm by volume means 8 mL of oxygen per \(10^6\) mL of water.

Step2: Match with options

Check each option:

• Option A: \(1000000\) mL of water. If 8 ppm, 8 mL O₂ in \(10^6\) mL water. This matches.
• Option B: 10000 mL water. 8 ppm would be \( \frac{8}{10^6} \times 10000 = 0.08 \) mL O₂, not 8.
• Option C: 1000 mL water. \( \frac{8}{10^6} \times 1000 = 0.008 \) mL O₂, not 8.
• Option D: 100 mL water. \( \frac{8}{10^6} \times 100 = 0.0008 \) mL O₂, not 8.

Answer:

A. 1 000 000 mL of water