container holding 340g of water (initially at 14 degrees celsius) is placed in microwave oven, which is turned on for 3 minutes. Assuming all microwave energy is absorbed by water, how much water is left in container?
4 answers
It would be helpful to know the radiation power of the microwave.
1000W
The microwave oven gives Q = P•t = 1000•180 =1.8•10^5 J.
The amount of heat necessary to heat the water to 100oC
Q1 = c•m1•Δt = 4180•0.340•86 =
= 1.22•10^5 J,
Q2 = Q – Q1 = 1.8•10^5 - 1.22•10^5 =
= 0.58•10^5 J.
This amount of heat transforms the mass m2 to the vapor
Q2 = r•m2 =2250000•m2,
m2 = 0.58•10^5/2250000 =2.58•10^-2 kg =0.0258 kg.
The amount of heat necessary to heat the water to 100oC
Q1 = c•m1•Δt = 4180•0.340•86 =
= 1.22•10^5 J,
Q2 = Q – Q1 = 1.8•10^5 - 1.22•10^5 =
= 0.58•10^5 J.
This amount of heat transforms the mass m2 to the vapor
Q2 = r•m2 =2250000•m2,
m2 = 0.58•10^5/2250000 =2.58•10^-2 kg =0.0258 kg.
Mass of left water is m1-m2= 0.340-0.0258 =0.31422 kg