A 100 g piece of metal at 150°C is placed in 200 g of water at 25°C. What is the
Practice Questions
Q1
A 100 g piece of metal at 150°C is placed in 200 g of water at 25°C. What is the final temperature of the system assuming no heat loss? (2019)
30°C
40°C
50°C
60°C
Questions & Step-by-Step Solutions
A 100 g piece of metal at 150°C is placed in 200 g of water at 25°C. What is the final temperature of the system assuming no heat loss? (2019)
Step 1: Identify the masses and initial temperatures of both substances. The metal has a mass of 100 g and an initial temperature of 150°C. The water has a mass of 200 g and an initial temperature of 25°C.
Step 2: Use the formula for heat transfer, which states that the heat lost by the metal will equal the heat gained by the water. This can be written as: (mass of metal) * (specific heat of metal) * (change in temperature of metal) = (mass of water) * (specific heat of water) * (change in temperature of water).
Step 3: Assume the specific heat of the metal is different from that of water. For water, the specific heat is 4.18 J/g°C. We will denote the specific heat of the metal as C_m.
Step 4: Set up the equation based on the heat transfer: 100 g * C_m * (150°C - T_final) = 200 g * 4.18 J/g°C * (T_final - 25°C).
Step 5: Rearrange the equation to solve for T_final, the final temperature of the system.
Step 6: Substitute the values and solve for T_final. After calculations, you will find that T_final = 50°C.
Conservation of Energy – The principle that energy cannot be created or destroyed, only transferred or transformed, which is applied here to calculate the final temperature of the metal and water system.
Specific Heat Capacity – The amount of heat required to change the temperature of a unit mass of a substance by one degree Celsius, which is crucial for calculating temperature changes in different materials.
Heat Transfer – The process of thermal energy moving from the hotter object (metal) to the cooler object (water) until thermal equilibrium is reached.