Pure water boils at 100 ∘ C, has a specific latent heat of vaporisation of 2260kJ/kg and a specific heat capacity of 4200J/(kg ∘ C).Part AEnergy to boil waterAll questions in this part are answered correctlyHow much energy is required for 2.0kg of water to boil away if it is already at 100 ∘ C?
Question
Pure water boils at 100 ∘ C, has a specific latent heat of vaporisation of 2260kJ/kg and a specific heat capacity of 4200J/(kg ∘ C).Part AEnergy to boil waterAll questions in this part are answered correctlyHow much energy is required for 2.0kg of water to boil away if it is already at 100 ∘ C?
Solution
The energy required to boil away water that is already at its boiling point can be calculated using the formula:
Q = mL
where:
- Q is the heat energy,
- m is the mass of the substance, and
- L is the specific latent heat of vaporisation.
Given that the mass of the water (m) is 2.0 kg and the specific latent heat of vaporisation (L) is 2260 kJ/kg, we can substitute these values into the formula:
Q = 2.0 kg * 2260 kJ/kg
This gives:
Q = 4520 kJ
So, 4520 kJ of energy is required for 2.0 kg of water to boil away if it is already at 100 ∘ C.
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