The specific latent heat of vaporisation of water is 2200 kJ kg, and the specific heat capacity of water is 4200 J/ kg.K. A heating ele

Question

The specific latent heat of vaporisation of water is 2200 kJ kg, and the specific
heat capacity of water is 4200 J/ kg.K. A heating element is immersed in an
insulated cup of water. It takes five minutes to boil the water completely from an
initial temperature of 30°C. Assuming no heat is lost to the surroundings,
determine the mass of the water if the heating element is operating at 1000 W.​

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Huyền Thanh 3 months 2021-08-12T23:54:27+00:00 1 Answers 1 views 0

Answers ( )

    0
    2021-08-12T23:55:50+00:00

    Answer:

    0.12 kg

    Explanation:

    The amount of energy added is:

    1000 W × (5 min × 60 s/min) = 300,000 J = 300 kJ

    Heat to boil the water is:

    q = mCΔT + mL

    q = m (CΔT + L)

    300 kJ = m (4.2 kJ/kg/K × (100°C − 30°C) + 2200 kJ/kg)

    300 kJ = m (2494 kJ/kg)

    m = 0.12 kg

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