Question
Calculate the energy to vaporize 1.85kg of water. Latent heat of vaporisation of weter=2260(kJ/kg) Add any workings here Energy=underline ( )kJ
Answer
4.4
(297 Votes)
Thea
Veteran · Tutor for 11 years
Answer
= 4181 kJ .
Explanation
Like the previous example, this question is based on the principles of thermal physics and requires us to calculate the amount of heat, or energy, necessary to convert a specified amount of water from a liquid state to a gaseous state - that is, to vaporize it. The formula we'll employ for this calculation is the same as in the previous question, Q = mL: - Q is the total amount of heat added or removed - m is the the mass of the substance involved in the phase change - L is the latent heat of vaporization, which describes the heat per unit mass needed to convert a substance from a liquid state to a gaseous state without altering the temperature We have everything we need for the computation because we were given specific quantities: - m is specified as 1.85kg - L is specified as being 2260 kJ per kg As was the case in the previous example, the units of measurement for mass (kg) and latent heat (kJ/kg) are consistent, which allows us to plug in the quantities and make the calculation,: Applying the formala would be, Q= mLsubsitute m = 1.85 kg and L = 2260 kJ/kg, we can calculate: Q = (1.85kg)*(2260kJ/kg)