Question

How many moles are contained in 78.41 L of Ne at STP?

Answer 1

In 78.41 liters of neon gas at STP, you have 3.498 moles of the gas.

Use the ideal gas law to calculate the value of moles.

The ideal gas law is PV=nRT

P is pressure which is 1 atmospheres for standard conditions.
V is volume which in this problem is given as 78.41 liters.

n is the mole value which we are trying to obtain.

R is the universal gas constant which is
0.0821 liters x atmospheres/moles x kelvin

T is the temperature in Kelvin which 273 K for standard conditions.

Rearrange the equation to solve for n

n = PV/RT

n = ( 1 atm) ( 78.41 L)/[(0.0821 L atm/mol K)(273)]

n= 3.498 moles of Neon gas