Hydrogen molecules (molar mass is equal to 2.016 g/mol) have an average velocity v. equal to 200 m/s. What is the temperature (In K)? Additional Materials eBook 6. [-/3 Points] DETAILS OSCOLPHYS2 13.6.P.050. (a) What is the vapor pressure (in Pa) of water at 10 C ? (b) What percentage of atmospheric pressure does this correspond to? (c) What percent of 10C air is water vapor if it has 100% relative humidity? (The density of dry air at 10.C is 1.25 kg/m .)