Question
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?
Answers
bobpursley
It would be helpful to know the radiation power of the microwave.
Dave
1000W
Elena
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.
Elena
Mass of left water is m1-m2= 0.340-0.0258 =0.31422 kg