Question

A piece of copper of mass 120g is heated in an enclosure to a temperature of 125 degrees. It is then taken out of the enclosure and held in air for half a minute and dropped carefully into a copper calorimeter of mass 105g containing 200g of water at 20 degrees Celsius. Calculate the rate at which heat is being lost from the copper when it is held in if the specific heat capacity of copper is 400.

a) 100 J/s
b) 150 J/s
c) 200 J/s
d) 250 J/s

Answer 1

The rate at which heat is being lost from the copper when it is held in air is approximately 160 J/s. Therefore the correct answer is b) 150 J/s.

Step-by-step explanation:

To calculate the rate at which heat is being lost from the copper when it is held in air, we can use the formula Q = mcΔT, where Q is the heat energy transferred, m is the mass of the copper, c is the specific heat capacity of copper, and ΔT is the change in temperature.

First, we need to calculate the initial temperature difference between the copper and the air. The initial temperature of the copper is 125°C, and the final temperature when it is held in air is not given, so we'll assume it is at room temperature, around 25°C.

Therefore, the initial temperature difference is 125°C - 25°C = 100°C. Next, we can calculate the rate of heat loss, Q/t, by dividing the heat energy transferred, Q, by the time, t. In this case, the time is half a minute or 30 seconds. The mass of the copper is 120g, and the specific heat capacity of copper is 400 J/kg·°C or 0.4 J/g·°C. Plugging in these values into the formula Q = mcΔT, we get Q = (120g)(0.4 J/g·°C)(100°C) = 4800 J.

Finally, we can calculate the rate of heat loss, Q/t, by dividing the heat energy transferred, Q, by the time, t: (4800 J) / (30s) = 160 J/s. Therefore, the rate at which heat is being lost from the copper when it is held in air is approximately 160 J/s.