In an iron saucepan weighing 500 g, you need to heat 2 kg of water from 20 to 100 degrees Celsius.

| January 8, 2021 | education

In an iron saucepan weighing 500 g, you need to heat 2 kg of water from 20 to 100 degrees Celsius. How much does it take to burn coal?

To find the value of the mass of burnt coal, we use the equality: qku * m1 = (Cw * m2 + Czh * m3) * (t – t0), whence we express: m1 = (Cw * m2 + Czh * m3) * (t – t0 ) / qku.
Constants and variables: Cv – beats. heat capacity of water (Cw = 4.2 * 103 J / (kg * K)); m2 is the mass of water (m2 = 2 kg); Szh – beats heat capacity of iron (Czh = 460 J / (kg * K)); m3 is the mass of the iron pan (m3 = 500 g = 0.5 kg); t is the final temperature of the pot with water (t = 100 ºС); t0 – initial temperature (t0 = 20 ºС); qku – beats. heat of combustion of coal (qku = 2.7 * 10 ^ 7 J / kg)
Calculation: m1 = (Cw * m2 + Czh * m3) * (t – t0) / qku = (4.2 * 10 ^ 3 * 2 + 460 * 0.5) * (100 – 20) / (2.7 * 107) = 25.57 * 10 ^ -3 kg = 25.57 g.
Answer: You need to burn 25.57 grams of coal.



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