Final answer:
To calculate the mass of fish needed to obtain a fatal dose of mercury, first convert the concentration to a decimal and then multiply by the mass of a fatal dose. The mass of fish required is approximately 0.006 kilograms. Option a
Step-by-step explanation:
To calculate the mass of fish needed to obtain a fatal dose of mercury, we need to convert the concentration of mercury in the fish to a mass.
First, we convert 30 parts per million (ppm) to a decimal by dividing by 1,000,000, which gives us 0.00003. Then, we multiply this decimal by the mass of the fish that would result in a fatal dose of mercury, which is 0.20 grams. This calculation gives us a mass of fish of 0.006 grams, or 0.006 kilograms.
Therefore, the correct answer is option a) 0.0067 kg.