JAMB - Physics (2015 - No. 1)
If the volume of a gas is recorded as 76cm3 at a temperature of 27°C with a pressure of 800mmHg. What will be the volume of the gas at S.T.P?
36.2cm3
25.7cm3
72.8cm3
24.3cm3
Explanation
Using the general gas laws:
\(\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}\)
P\(_1\) = 800mmHg, V\(_1\) = 76cm\(^3\), T\(_1\) = 273 + 27 = 300k
P\(_2\) = 760mmHg, V\(_2\) = ? T\(_2\) = 273 + 0 = 273 (@ STP)
\(\frac{800 \times 76}{300} = \frac{760 \times V_2}{273}\)
V\(_2 = \frac{800 \times 76 \times 273}{300 \times 760}\) = 72.8cm\(^3\)
Therefore, the volume of gas at S.T.P = 72.8 cm\(^3\)
\(\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}\)
P\(_1\) = 800mmHg, V\(_1\) = 76cm\(^3\), T\(_1\) = 273 + 27 = 300k
P\(_2\) = 760mmHg, V\(_2\) = ? T\(_2\) = 273 + 0 = 273 (@ STP)
\(\frac{800 \times 76}{300} = \frac{760 \times V_2}{273}\)
V\(_2 = \frac{800 \times 76 \times 273}{300 \times 760}\) = 72.8cm\(^3\)
Therefore, the volume of gas at S.T.P = 72.8 cm\(^3\)
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