Mixed 5 liters of water with a temperature of 9 degrees Celsius with boiling water.

Mixed 5 liters of water with a temperature of 9 degrees Celsius with boiling water. Mix temperature = 30 degrees Celsius. What mass of boiling water was mixed with water.

Given: Vx (volume of cold water) = 5 l (in SI Vx = 0.005 m3); tx (cold water temperature) = 9 ºС; tc (temperature of the mixture obtained) = 30 ºС.

Reference values: tк (boiling water temperature) = 100 ºС; ρ (water density) = 1000 kg / m3.

We express the mass of boiling water that needed to be mixed with water from the equality: С * ρ * Vx * (tс – tх) = С * mк * (tк – tс), whence mк = С * ρ * Vx * (tс – tх) / (C * (tc – tc)) = ρ * Vx * (tc – tx) / (tc – tc).

Calculation: mk = 1000 * 0.005 * (30 – 9) / (100 – 30) = 1.5 kg.