Aflask contains 2.0 mol of he gas at 25°c and 1.00 atm. how much he gas, in grams, must be added to increase the pressure to 2.00 atm at constant temperature and volume?

Mass of He required = 8.0 g

Explanation:

Given,

Initial moles of He = 2.0 mol

Initial pressure = 1.00 atm

final pressure = 2.00 atm

Ideal gas equation,

PV = nRT

As V, R and T are constant

So,

Molar mass of He = 4.00 g/mol

No. of moles of He needs to be added = 4.0 - 2.0 = 2.0 mol

Mass = No. of mole × Molar mass

         = 2.0 × 4.0

          = 8.0 g

no

explanation:

go away, people want answers, not to hook up

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons