physics
posted by Mark .
A storage tank at stp contains 18.5kg of nitrogen. What is the volume of the tank and what would the pressure be if you added another 15kg of nitrogen at the same temperature?

Nitrogen gas (N2) has a mass of 28.0 grams per mole, and one mole occupies 22.4 liters at STP.
You have a mass of 18,500 g. Divide that by 28 g/mol for the number of moles. Then multiply that by 22.4 liter/mol for the number of liters.
If you add 15 kg to the 18.5 kg you already have, keeping T the same, you multiply the number of moles and the pressure by a factor
33.5/18.5 
Thanks