Natural gas consists of about 90% methane, CH₄. Assume that the solubility of natural gas at 20 °C and 1 atm gas pressure is about the same as that of CH₄, 0.02 g/kg water. If a sample of natural gas under a pressure of 20 atm is kept in contact with 1.00 x 10³ kg of water, what mass of natural gas will dissolve?