Question

Calculate the volume occupied by 5 g of acetylene gas at 5 c and 740 mm pressure

Answer 1

Applying the general gas equation

PV = nRT = m/M RT

Here, Mol. wt. of acetylene i.e., C2H2 (M) = 26, P = 740/760 atm,

T = 50oC = 50 + 273 = 323 K

∴ V = mRT/MP or V 5 * 0.082 *323 *760/26 *740 = 5.23 l

Answer 2

Answer: The volume occupied by the gas is  4.5 L

Explanation:

To calculate the volume of acetylene gas, we use the equation given by ideal gas:

$PV=\frac{m}{M}RT$

where,

P = Pressure of acetylene gas = 740 mmHg

V = Volume of the acetylene gas = ?

m = mass of acetylene gas = 5 g

M = molar mass of acetylene gas = 26 g/mol

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

T = Temperature of acetylene gas = $5^oC=[273+5]K=278K$

Putting values in above equation, we get:

$740mmHg\times V=\frac{5g}{26g/mol}\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 278K\\\\\V=4.5L$

Hence, the volume occupied by gas is 4.5 L.