What happens to water molecules when water is heated from 90 degrees Celsius to 110 degrees Celsius
a) They condense
b) They evaporate
c) They freeze
d) They remain unchanged
The Correct Answer and Explanation is :
The correct answer is b) They evaporate.
When water is heated from 90 degrees Celsius to 110 degrees Celsius, the water molecules gain kinetic energy, which increases their temperature. As the temperature of the water rises, the molecules move more rapidly. At 90 degrees Celsius, the water is still in the liquid state, but as it approaches 100 degrees Celsius, it reaches its boiling point at standard atmospheric pressure.
At this boiling point, water molecules begin to escape from the liquid phase into the gas phase, a process known as evaporation. Evaporation occurs at all temperatures, but it becomes more pronounced as the temperature rises. When water is heated above its boiling point, such as at 110 degrees Celsius, the rate of evaporation significantly increases. This is because more molecules have enough energy to overcome the intermolecular forces that hold them in the liquid state.
As the water continues to be heated, it can enter a phase where it is not just boiling but superheating. In this state, the water can remain liquid even above 100 degrees Celsius, but it is in a metastable state. The molecules are constantly moving, and the vapor pressure increases, leading to rapid evaporation when conditions allow for bubble formation.
In summary, heating water from 90 degrees Celsius to 110 degrees Celsius results in an increase in the kinetic energy of the water molecules, leading to an increase in the rate of evaporation. This is a direct result of the molecules gaining enough energy to break free from the attractive forces of neighboring molecules, transitioning from the liquid phase to the gaseous phase.