Carbon dioxide gas has a solubility of 0.0972g/100g H2O at 40. Expressed in parts per million, this concentration is closest to

a) 0.972ppm
b) 9.72ppm
c) 97.2ppm
d) 972ppm

d

To determine the concentration of carbon dioxide gas (CO2) in parts per million (ppm), we need to convert the given solubility in grams of CO2 per 100 grams of water into ppm.

First, we can calculate the concentration in grams of CO2 per gram of water:
0.0972 g CO2 / 100 g H2O = 0.000972 g CO2 / g H2O

Next, we convert the concentration of CO2 in grams per gram of water to the concentration in ppm. Since ppm is a unit of concentration relative to 1 million, we multiply the concentration by 1,000,000:
0.000972 g CO2 / g H2O * 1,000,000 ppm/g = 972 ppm

Therefore, the concentration of carbon dioxide gas in parts per million (ppm) is 972 ppm. So, the correct answer is (d) 972 ppm.