How many degrees did 20 liters of boiling water cool if it gave 1000 kJ of heat to the environment?

Data: V (volume of taken boiling water) = 20 l (in SI V = 0.02 m3); Q (the heat that the boiling water gave to the environment) = 1000 kJ (1 * 10 ^ 6 J).

Reference values: Sv (specific heat of boiling water, water) = 4200 J / (kg * K); ρw (density of boiling water, water) = 1000 kg / m3.

The change in the boiling water temperature during the transfer of heat to the environment is expressed from the formula: Q = Sv * ρw * V * Δt, whence Δt = Q / (Sv * ρw * V).

Let’s calculate: Δt = 1 * 10 ^ 6 / (4200 * 1000 * 0.02) = 11.9 ºС.

Answer: The boiling water has cooled down by 11.9 ºС.



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