Question

Which of the following statements is true for real gases?

Choose all that apply.
A. The volume occupied by the molecules can cause an increase in pressure compared to the ideal gas.
B. The volume occupied by the molecules can cause a decrease in pressure compared to the ideal gas.
C. As molecules increase in size, deviations from ideal behavior become more apparent at relatively low pressures.
D. As attractive forces between molecules increase, deviations from ideal behavior become more apparent at relatively low temperatures.

Answer 1

Answer:

A. The volume occupied by the molecules can cause an increase in pressure compared to the ideal gas.

D. As attractive forces between molecules increase, deviations from ideal behavior become more apparent at relatively low temperatures.

Explanation:

as we know by real gas equation

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

while ideal gas equation is given as

$PV = nRT$

so from above formula we can say that net pressure is increased in real gas

Also we know that all real gas will close to behave like ideal gas when the pressure of the real gas is low and temperature of the gas is high

So above are the correct observations

Answer 2

Answer: Option (D) is the correct answer.

Explanation:

In real gases, there exists force of attraction between the molecules at low temperature and high pressure. This is because at low temperature there occurs a decrease in kinetic energy of gas molecules and high pressure causes the molecules to come closer to each other.

As a result, forces of attraction increases as molecules come closer to each other and therefore, gases deviate from an ideal gas behavior.

And, at low pressure and high temperature there exists no force of attraction or repulsion between the molecules of a gas. Hence gases behave ideally at these conditions.

Thus, we can conclude that the statement as attractive forces between molecules increase, deviations from ideal behavior become more apparent at relatively low temperatures, is true for real gases.