Answer to Question #181211 in General Chemistry for andrew

Question

Calculate the number of moles of O2 gas held in a sealed 2.00 L tank at 3.50 atm and 25.0 ℃. How many moles would be in the tank if the temperature was raised to 49.0 ℃, but pressure and volume stayed the same?

Answer 1

We will apply the Ideal gas Equation;

PV = nRT

In part I of the question we have;

P=3.50 atm

V=2.00 L

T = (25^oC + 273) = 298 K

R= 0.0821 L*atm*mol^-1*K^-1 (because pressure is in atm)

We are interested in finding the value of n

If we rearrange the equation we get;

$n=\dfrac{PV}{RT}$

$n=\dfrac{3.50 atm x 2.00L}{0.0821 L*atm*mol^-1*K^-1 x 298K}$

= 0.286 mol

In part II we have

P= 3.50 atm

V= 2.00 L

R=(40.0^oC + 273) = 313 K

Thus solving for n we have;

$n=\dfrac{3.50 atm x 2.00L}{0.0821L*atm*mol^-1*K^-1 x 313 K}$

n = 0.272 mol