Convert 0.005 ppm to ppb.

To convert parts per million (ppm) to parts per billion (ppb), you need to know the relationship between these two units. One part per million (ppm) is equivalent to 1,000 parts per billion (ppb). Therefore, when you want to convert a value from ppm to ppb, you multiply the ppm value by 1,000.

In this case, you're converting 0.005 ppm to ppb. By applying the conversion factor:

0.005 ppm × 1,000 ppb/ppm = 5 ppb

This calculation shows that 0.005 ppm equals 5 ppb, confirming that the correct answer is 5. Understanding the conversion factor is crucial for accurately moving between these two units of measurement, particularly in environmental science, where concentrations of substances in water are often expressed in these terms.