Real gases will approach the behaviour of ideal gases at

Answer

To determine the conditions under which real gases behave like ideal gases, we can analyze the differences between the equations governing real gases and ideal gases.

### Step-by-Step Solution:

1. **Understanding the Ideal Gas Law**:
The ideal gas law is given by the equation:
\[ PV = nRT \]
Here, \( P \) is pressure, \( V \) is volume, \( n \) is the number of moles, \( R \) is the universal gas constant, and \( T \) is temperature. This equation assumes that gas particles do not interact and occupy no volume.

2. **Understanding the Real Gas Equation**:
The real gas behavior is described by the Van der Waals equation:
\[ \left(P + \frac{a n^2}{V^2}\right)(V - nb) = nRT \]
In this equation, \( a \) accounts for the attractive forces between gas molecules, and \( b \) accounts for the volume occupied by the gas molecules themselves.

3. **Conditions for Ideal Behavior**:
To convert the real gas equation to the ideal gas equation, we need to minimize the effects of the constants \( a \) and \( b \):
- **High Temperature**: At high temperatures, the kinetic energy of gas molecules increases, causing them to move further apart. This reduces the effect of intermolecular forces, making \( a \) approach zero.
- **Low Pressure**: At low pressures, gas molecules are also further apart, which means the volume occupied by the gas molecules (represented by \( b \)) becomes negligible. Thus, \( b \) approaches zero.

4. **Conclusion**:
Therefore, real gases will behave like ideal gases under the conditions of **high temperature and low pressure**.

### Final Answer:
Real gases will approach the behavior of ideal gases at **high temperature and low pressure**.

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