A 1 kg block of metal at 100°C is placed in 2 kg of water at 20°C. Assuming no h
Practice Questions
Q1
A 1 kg block of metal at 100°C is placed in 2 kg of water at 20°C. Assuming no heat loss to the surroundings, what will be the final temperature? (Specific heat of water = 4.2 kJ/kg°C) (2022)
25°C
30°C
35°C
40°C
Questions & Step-by-Step Solutions
A 1 kg block of metal at 100°C is placed in 2 kg of water at 20°C. Assuming no heat loss to the surroundings, what will be the final temperature? (Specific heat of water = 4.2 kJ/kg°C) (2022)
Step 1: Identify the mass and initial temperature of the metal block. The mass is 1 kg and the initial temperature is 100°C.
Step 2: Identify the mass and initial temperature of the water. The mass is 2 kg and the initial temperature is 20°C.
Step 3: Use the formula for heat transfer: Q = mcΔT, where Q is heat, m is mass, c is specific heat, and ΔT is the change in temperature.
Step 4: Set up the equation for heat lost by the metal: Q_metal = m_metal * c_metal * (T_initial_metal - T_final).
Step 5: Set up the equation for heat gained by the water: Q_water = m_water * c_water * (T_final - T_initial_water).
Step 6: Since no heat is lost to the surroundings, set the heat lost by the metal equal to the heat gained by the water: Q_metal = Q_water.
Step 7: Substitute the known values into the equation and solve for T_final, the final temperature.
Conservation of Energy – The principle that energy cannot be created or destroyed, only transferred; in this case, heat lost by the metal equals heat gained by the water.
Specific Heat Capacity – The amount of heat required to change the temperature of a unit mass of a substance by one degree Celsius; important for calculating heat transfer.
Heat Transfer – The process of thermal energy moving from a hotter object (metal) to a cooler one (water) until thermal equilibrium is reached.
