Problem 83 - Chemistry: The Central Science

Question

(a) List two experimental conditions under which gases deviate from ideal behavior. (b) List two reasons why the gases deviate from ideal behavior. (c) Explain how the function \(P V / R T\) can be used to show how gases behave nonideally.

Step-by-Step Solution

Answer

(a) Gases deviate from ideal behavior under high pressure and low temperature conditions. (b) Deviation occurs due to intermolecular forces and the actual volume occupied by gas particles. (c) The function \(PV/RT\) can be used to show nonideal behavior, as gases with a value that deviates from \(1\) indicate nonideality.

Step 1: (a) Explain Two Experimental Conditions Under Which Gases Deviate from Ideal Behavior

There are several experimental conditions that lead to deviation from ideal behavior. Here are two such conditions: 1. High pressure: Gases deviate from ideal behavior when the pressure is high because under high pressure conditions, the gas particles are pushed closer together, causing particle interactions and volume occupancies that were initially negligible to become significant. 2. Low temperature: Deviation from ideal behavior is observed at low temperatures because, as the temperature decreases, gas particles move more slowly and have more time to interact. These interactions between gas particles become more apparent at lower temperatures.

Step 2: (b) List Two Reasons Why Gases Deviate from Ideal Behavior

Gases deviate from ideal behavior for various reasons. Here are two significant factors: 1. Intermolecular forces: At high pressure and low temperature, the intermolecular forces between gas particles become more pronounced and affect the gas' behavior. These molecular forces are not taken into account in the ideal gas law, causing deviations. 2. Particle size: In the ideal gas law, gas particles are assumed to have negligible volume. However, as pressure increases and/or temperature decreases, the volume occupied by the gas particles can no longer be considered negligible, leading to deviations from ideal behavior.

Step 3: (c) Explain How the Function \(PV/RT\) Can Be Used to Show How Gases Behave Nonideally

The function \(PV/RT\) is derived from the ideal gas law, where \(P\) represents pressure, \(V\) represents volume, \(n\) represents the number of moles, \(R\) is the ideal gas constant, and \(T\) is the temperature. In an ideal gas, the value of \(PV/RT = 1\). However, a gas that does not follow ideal behavior will have a \(PV/RT\) value that deviates from \(1\). The deviation of the ratio from 1 indicates the degree of nonideality of the gas. By comparing the \(PV/RT\) values of different gases under various conditions (e.g., high pressure or low temperature), we can determine the extent to which a particular gas deviates from ideal behavior. Additionally, comparing these values can help us understand the effects of particle size and intermolecular forces on the gas' behavior.