Question

In blacksmithing, quenching is when you heat steel to 600°C, then dipping it into a pool of oil to quickly lower its temperature. Steel has a specific heat capacity of 470 J/kgK, and quenching oil has a specific heat capacity of 510 J/kgK. A 7kg sword was quenched in 20°C oil, reaching a final temperature of 75°C. What was the total mass of oil in that quenching pool?

Answer 1

The amount of heat lost by the sword is equal to the amount of heat gained by the oil. We can use the formula:

Q = mcΔT

where Q is the heat transferred, m is the mass of the object, c is the specific heat capacity, and ΔT is the change in temperature.

The heat lost by the sword is:

Q_sword = mcΔT = (7 kg)(470 J/kgK)(600°C - 75°C) = 2,835,000 J

The heat gained by the oil is:

Q_oil = mcΔT = (m_oil)(510 J/kgK)(75°C - 20°C)

We can solve for m_oil:

Q_oil = Q_sword

(m_oil)(510 J/kgK)(55°C) = 2,835,000 J

m_oil = 104,706 kg

Therefore, the total mass of oil in the quenching pool was 104,706 kg.