Calculate Moles and Volume

Question

Given the following amounts of gasses, calculate the number of moles of each gas. Calculate the volume of each amount of gas would occupy at 100°C and 15atm. 

a. 5.8g NH₃

b. 48g O₂

c. 10.8g He

Answer 1

a). 5.8 g NH3 x 1 mol NH3 / 17 g NH3 = 0.34 moles NH3

PV = nRT (note: change temp of 100C to 373 K)

V = nRT/P = (0.34 mol)(0.0821 Latm/Kmol)(373K) / 15 atm = 0.69 liters

do the others the same way. Convert grams of material to moles by using the molar mass and then use the moles to find volume using PV = nRT just as in (a) above.