Question

Under which conditions of temperature and pressure would helium behave most like an ideal gas?
(1) 50 K and 20 kPa (3) 750 K and 20 kPa
(2) 50 K and 600 kPa (4) 750 K and 600 kPa

Answer 1

Answer : The correct option is, (3) 750 K and 20 kPa

Explanation :

The conditions for ideal gas are :

Ideal gas are those gas that has no intermolecular attractions.

Ideal gas are those gas that have negligible volume.

The ideal gas equation is,

$PV=nRT$

The conditions for real gas are :

Real gas are those gas that have intermolecular attractions.

Real gas are those gas that have volume.

The real gas equation is,

$(P+\frac{an^2}{V^2})(V-nb)=nRT$

A real gas behave ideally at high temperature and low pressure condition.

From the given options, option (3) have high temperature and low pressure is the correct option.

Hence, at 750 K and 20 kPa conditions of temperature and pressure does a sample of helium behave most like an ideal gas.