How much gasoline do you need to burn to heat 500 ml water to 20 degrees Celsius? Neglect heat loss.

To find the mass of gasoline expended for heating water, you can use the equality (no heat loss): qb * m = Sv * ρ * V * Δt and m = Sv * ρ * V * Δt / qb.

Variables and constants: Sv – heat capacity of water (Sv = 4200 J / (kg * K)); ρ is the density of water (ρ = 1000 kg / m3); V is the volume of water (V = 500 ml = 500 * 10 ^ -6 kg); Δt – temperature change (Δt = 20 ºС); qb is the heat of combustion of gasoline (qb = 4.6 * 10 ^ 7 J / kg).

Calculation: m = 4200 * 1000 * 500 * 10 ^ -6 * 20 / (4.6 * 10 ^ 7) = 9.13 * 10 ^ -4 kg or 0.913 g.