Choose the correct statement with respect to the vapour pressure of a ...
Vapour pressure is defined as the pressure exerted by the vapours above the liquid surface in equilibrium with the liquid at a given temperature. The vapour pressure of a liquid increases non-linearly with increasing temperature.
This is because kinetic energy is the function of temperature which means that as the temperature is increased, more molecules will have greater kinetic energies and thus they can escape from the surface of the liquid to the vapour phase resulting in higher vapour pressure.
Choose the correct statement with respect to the vapour pressure of a ...
Introduction:
The vapor pressure of a liquid is the pressure exerted by its vapor when the liquid and its vapor are in equilibrium at a given temperature. It is an important property of liquids that determines their boiling points and evaporation rates. The relationship between vapor pressure and temperature is described by the Clausius-Clapeyron equation.
Explanation:
The correct statement with respect to the vapor pressure of a liquid is option 'B', which states that vapor pressure increases non-linearly with increasing temperature. This means that as the temperature of a liquid increases, its vapor pressure also increases, but the rate of increase is not constant.
Reasoning:
1. The behavior of vapor pressure with temperature can be explained by the kinetic energy of the molecules in the liquid.
2. As the temperature increases, the average kinetic energy of the molecules also increases.
3. This leads to an increase in the number of molecules with enough energy to escape the liquid phase and enter the vapor phase.
4. Consequently, the vapor pressure of the liquid increases as more molecules are able to escape into the vapor phase.
5. However, the relationship between vapor pressure and temperature is not linear because the kinetic energy distribution of molecules follows a Boltzmann distribution.
6. The Boltzmann distribution describes the distribution of molecular energies in a system and shows that the number of molecules with higher energy increases exponentially with temperature.
7. Therefore, as the temperature increases, the increase in vapor pressure becomes more significant due to the exponential increase in the number of molecules with enough energy to escape into the vapor phase.
8. This non-linear relationship between vapor pressure and temperature is accurately described by the Clausius-Clapeyron equation, which takes into account the enthalpy of vaporization and the temperature dependence of vapor pressure.
Conclusion:
In summary, the vapor pressure of a liquid increases non-linearly with increasing temperature. This is due to the exponential increase in the number of molecules with enough energy to escape into the vapor phase as the temperature increases. The Clausius-Clapeyron equation provides a mathematical description of this relationship and allows for the calculation of vapor pressure at different temperatures.
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