A 1 kg block of ice at 0°C is placed in 2 kg of water at 80°C. What will be the
Practice Questions
Q1
A 1 kg block of ice at 0°C is placed in 2 kg of water at 80°C. What will be the final temperature of the mixture? (Assume no heat loss to the surroundings) (2019)
0°C
40°C
60°C
80°C
Questions & Step-by-Step Solutions
A 1 kg block of ice at 0°C is placed in 2 kg of water at 80°C. What will be the final temperature of the mixture? (Assume no heat loss to the surroundings) (2019)
Step 1: Understand that we have a 1 kg block of ice at 0°C and 2 kg of water at 80°C.
Step 2: Know that when the ice is placed in the water, the water will lose heat and the ice will gain heat.
Step 3: Remember that the heat lost by the water will equal the heat gained by the ice (this is called the conservation of energy).
Step 4: Realize that the ice will first melt into water at 0°C before it can increase in temperature.
Step 5: Calculate the heat needed to melt the ice: it takes 334 kJ to melt 1 kg of ice.
Step 6: Calculate the heat lost by the water as it cools down from 80°C to 0°C: it takes 2 kg of water and a specific heat capacity of 4.18 kJ/kg°C.
Step 7: Compare the heat lost by the water to the heat gained by the ice. If the heat lost by the water is enough to melt the ice, the final temperature will be 0°C.
Step 8: Conclude that since the water can provide enough heat to melt the ice, the final temperature of the mixture will be 0°C.
Heat Transfer – The principle of conservation of energy where heat lost by the warmer substance equals heat gained by the cooler substance.
Phase Change – Understanding that ice at 0°C will absorb heat to melt before the temperature of the mixture can increase.
