1. The problem statement, all variables and given/known data Zinc metal is added to hydrochloric acid to generate hydrogen gas and is collected over a liquid whose vapor pressure is the same as that of pure water at 20.0°C (18 torr). The volume of the mixture is 1.7 L, and its total pressure is 0.987 atm. Determine the number of moles of hydrogen gas present in the sample. a. 0.272 mol b. 0.04 mol c. 0.997 mol d. 0.139 mol e. 0.0681 mol So theres some container with a volume of 1.7L and pressure of 0.987.... The amount of hydrogen and the other substance in the container are unknown. We also know that the other substance has the same pressure as water does at 20C, (i don't think we use the temperature to find the solution)... And we know the pressure of the other substance is 18torr. Note; i'm not sure if the question is saying the pressure of water/the substance at 20C is 18torr. Or if the temperature of the substance is the same as water when the substance is 20C.