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Question
Solve the following problem.
Specific latent heat of vaporization of water is 2.26 × 106 J/kg. Calculate the energy needed to change 5.0 g of water into steam at 100 ºC.
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Solution
Given: Lvap = 2.26 × 106 J/kg, m = 5g = 5 × 10-3 kg
In this case, no temperature change takes place an only a change of state occurs.
To find: Heat required to convert water into steam.
Formula: Heat required = mLvap
Calculation: From formula,
Heat required = 5 × 10-3 × 2.26 × 106
= 11300 J
= 1.13 × 104 J
Heat required to convert water into steam is 1.13 × 104 J.
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