Determine the mass of water that can be heated from 20 s to boiling by burning 30 kg of coal?
| April 21, 2021 | education
t1 = 20 ° C.
t2 = 100 ° C.
C = 4200 J / kg * ° C.
q = 2.7 * 10 ^ 7 J / kg.
mу = 30 kg.
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The amount of heat Qw required for heating water is expressed by the formula: Qw = C * mw * (t2-t1).
When coal is burned, the amount of heat Qу is released, which is determined by the formula: Qу = q * mу.
If we neglect the loss of thermal energy, then Qw = Qy.
C * mw * (t2 – t1) = q * mu.
mv = q * mу / C * (t2 – t1).
mw = 2.7 * 10 ^ 7 J / kg * 30 kg / 4200 J / kg * ° C * (100 ° C – 20 ° C) = 2410.7 kg.
Answer: when burning coal, you can heat mw = 2410.7 kg of water.
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