A sample of helium gas has a volume of 900. milliliters and a pressure of 2.50 atm at 298 K. What is the new pressure when the temperature is changed to 336 K and the volume is decreased to 450. milliliters?

The new pressure = 5.64 atm.

Explanation:

Using The general gas equation,

P₁V₁/T₁ = P₂V₂/T₂ ... Equation 1

making P₂ the subject of the equation

P₂ = P₁V₁T₂/V₂T₁ ... Equation 2

Where P₁ = initial pressure, V₁ = initial Volume, T₁ = Initial temperature, P₂ = final pressure, V₂ = final volume, T₂ = final Temperature.

Given: P ₁ = 2.5 atm, T₁ = 298 K, V₁ = 900 milliliters, T ₂ = 336 K, V₂ = 450 milliliters

Substituting these values into equation 2,

P₂ = (2.5*900*336) / (298*450)

P₂ = 756000/134100

P₂ = 5.64 atm.

Thus the new pressure = 5.64 atm.