How many of the following physical properties are extensive:
(i) Free energy (ii) vapour pressure (iii) mole (iv) kinetic energy
(v) Entropy (vi) Internal energy (vii) Enthalpy (viii) specific heat capacity
(ix) Coefficient of viscosity

Explanation

To determine how many of the given physical properties are extensive, we first need to understand what extensive properties are. Extensive properties are those that depend on the amount of substance present. In contrast, intensive properties do not depend on the quantity of substance.

Let's analyze each of the given properties:

1. **Free Energy**:
- Free energy is an extensive property because it depends on the amount of substance. More substance means more free energy.

2. **Vapour Pressure**:
- Vapour pressure is an intensive property because it does not depend on the amount of substance. It remains the same regardless of how much substance is present.

3. **Mole**:
- The mole is an extensive property since it directly relates to the quantity of substance. For example, 18 grams of water corresponds to 1 mole, while 36 grams corresponds to 2 moles.

4. **Kinetic Energy**:
- Kinetic energy is an extensive property because it depends on the mass of the substance. More mass means more kinetic energy.

5. **Entropy**:
- Entropy is also an extensive property as it is directly related to the amount of substance present. More substance results in greater entropy.

6. **Internal Energy**:
- Internal energy is an extensive property because it is proportional to the amount of substance. More substance means more internal energy.

7. **Enthalpy**:
- Enthalpy is an extensive property as well, as it depends on the amount of substance. More substance leads to higher enthalpy.

8. **Specific Heat Capacity**:
- Specific heat capacity is an intensive property because it is defined as the heat capacity per unit mass. It does not change with the amount of substance.

9. **Coefficient of Viscosity**:
- Coefficient of viscosity is an intensive property because it does not depend on the amount of substance. It remains constant regardless of the quantity.

Now, let's summarize the findings:

- Extensive properties: Free Energy, Mole, Kinetic Energy, Entropy, Internal Energy, Enthalpy (Total: 6)
- Intensive properties: Vapour Pressure, Specific Heat Capacity, Coefficient of Viscosity (Total: 3)

**Final Count of Extensive Properties**: 6

### Summary:
Out of the 9 properties listed, 6 are extensive properties.

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