What volume will 40.0 L of He at 50.00°C
and 1201 torr occupy at STP?

we can use the combined gas law equation as the amount of gas is constant in both instances.

\frac{P1V1}{T1} = \frac{P2V2}{T2}

T1

P1V1

=

T2

P2V2

P - pressure , V- volume and T - temperature in kelvin

parameters at STP are on the left side and parameters for the second instance are on the right side of the equation

P1 - 101 325 Pa

T1 - 273 K

V1 - 15.0 L

P2 - 735 Torr x 133 Pa/Torr = 97 755 Pa

T2 - 57 °C + 273 = 330 K

substituting these values in the equation

\frac{101 325Pa *15.0 L}{273K} = \frac{97755Pa*V}{330K}

273K

101325Pa∗15.0L

=

330K

97755Pa∗V

V = 18.8 L

the volume it occupies at the given conditions is 18.8 L

there is none because earth is stationary and flat.