Question

How much heat is required to convert 500g of liquid water at 28°C into steam at 150°C? Take the specific heat capacity of water to be 4183J/kg°C and the latent heat of vaporization to be 2.26×10⁶J/kg

Answer 1

1,327,063Joules

Step-by-step explanation:

Heat energy is the energy needed to convert the state of a body from one phase to another.

According to the question, we want to calculate the total heat required to convert water into vapour (steam).

Note that before water can vapourize, it has to reach the boiling point first which is at 100°C. Heat energy needed to convert the water to 100°C is expressed as H1 = mcΔθ

m is the mass of the object in kg =0.5kg

c is the spcific heat capacity of water = 4183J/kg°C

Δθ is the change in temperature = 100-28 = 72°C

H1 = 0.5*4183*72

H1 = 150,588Joules

Energy required to convert the water to team H2 =mLsteam

Lsteam is the latent heat of vaporization = 2.26×10⁶J/kg

H2 = 0.5*2.26×10⁶

H2 = 1130000Joules

Heat energy needed to convert the water to 150°C is expressed as H3 = mcΔθ

m is the mass of the object in kg =0.5kg

c is the spcific heat capacity of steam= 1859J/kg°C

Δθ is the change in temperature = 150-100 = 50°C

H3 = 0.5*1859*50

H1 = 46,475Joules

Total Heat requires = H1+H2+H3 = 150,588Joules+1130000Joules+ 46,475Joules = 1,327,063Joules