Ice weighing 2.5 kg at a temperature of -20 degrees Celsius was melted, then this water was heated to 100 degrees
Ice weighing 2.5 kg at a temperature of -20 degrees Celsius was melted, then this water was heated to 100 degrees Celsius and then completely evaporated. How much energy was required for this, how much kerosene was burned?
m = 2.5 kg.
t1 = -20 ° C.
t2 = 0 ° C.
t3 = 100 ° C.
Cl = 2100 J / kg * ° C.
q = 3.4 * 10 ^ 5 J / kg.
Cw = 4200 J / kg * ° C.
λ = 2.3 * 10 ^ 6 J / kg.
k = 4.6 * 10 ^ 7 J / kg.
mk -?
Q = Q1 + Q2 + Q3 + Q4.
Q1 = Cl * m * (t2 – t1).
Q1 = 2100 J / kg * ° C * 2.5 kg * (0 ° C – (- 20 ° C)) = 105000 J.
Q2 = q * m.
Q2 = 3.4 * 10 ^ 5 J / kg * 2.5 kg = 850,000 J.
Q3 = Cв * m * (t3 – t2).
Q3 = 4200 J / kg * ° C * 2.5 kg * (100 ° C – 0 ° C) = 1050000 J.
Q4 = λ * m.
Q4 = 2.3 * 10 ^ 6 J / kg * 2.5 kg = 5750000 J.
Q = 105000 J + 8500000 J + 1050000 J + 5750000 J = 7755000 J.
Q = k * mk.
mk = Q / k.
mk = 7755000 J / 4.6 * 10 ^ 7 J / kg = 0.17 kg.
Answer: Q = 7755000 J, mk = 0.17 kg.