To heat 1.55 liters of water at 80 K on an alcohol lamp, 80 g of alcohol were consumed.

To heat 1.55 liters of water at 80 K on an alcohol lamp, 80 g of alcohol were consumed. Determine the efficiency of the spirit lamp.

To determine the efficiency of the spirit lamp used, we will use the formula: η = Qw / Qz = Sv * mw * ΔT / (qsp * msp).

Const: St. – beats. heat capacity of water (Sv = 4.18 * 10 ^ 3 J / (kg * K)); qsp – beats. the heat of combustion of alcohol (qsp = 2.7 * 10 ^ 7 J / kg).

Data: mw is the mass of water (V = 1.55 l corresponding to mw = 1.55 l); Δt – change, increase in temperature (Δt = 80 K); msp is the mass of consumed alcohol (msp = 80 g, in the SI system msp = 0.08 kg).

Let’s calculate: η = 4.18 * 10 ^ 3 * 1.55 * 80 / (2.7 * 10 ^ 7 * 0.08) ≈ 0.24 or 24%.

Answer: The efficiency of the used spirit lamp is 24%.