The volume of gas under STP is 0.512 liters.
Explanation:
At STP (Standaed Temperature and Pressure)
T = 0°C
P = 1 atm = 760 mmHg
Given
P1 = 756 mmHg
T1 = -21.5°C = -21.5 + 273 = 251.5 K
V1 = 475 mL = 0.475 L
P2 = 760 mmHg
T1 = 0°C = 0 + 273 = 273 K
We know that
[tex]\frac{P1 \times V1}{T1} = \frac{P2 \times V2 }{T2}\\\\\frac{756 \times 0.475}{251.5} = \frac{760 \times V2}{273}\\[/tex]
[tex]V2 = \frac{273 \times 756 \times 0.475}{251.5 \times 760} \\V2 = \frac{98034.3}{191140}[/tex]
V2 = 0.512 L
