How much gasoline needs to be burned to heat 200 kg of water to 30C

To calculate the mass of gasoline burned, we will use the heat balance equation: Q1 = Q2; Sv * m1 * Δt = qb * m2, whence we express: m2 = Sv * m1 * Δt / qb.

Constants and variables: Sv – heat capacity of water (Sv = 4200 J / (kg * K)); m1 is the mass of water (m1 = 200 kg); Δt is the required temperature change (Δt = 30 ºС); qb is the heat of combustion of gasoline (qb = 4.6 * 10 ^ 7 J / kg).

Calculation: m2 = Sv * m1 * Δt / qb = 4200 * 200 * 30 / (4.6 * 10 ^ 7) = 0.548 kg (548 g).

Answer: You need to burn 548 g of gasoline.