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1 vote
You are given the following information, where C represents the specific heat capacity of a material.

For ethanol:

C=2.671 J/g•°C

For water.

C=4.184 J/g•°C

You have two identical containers, one contains 100.0 g of ethanol, and the other contains 100.0 g of water. Each sample starts at 75.0°C. The two samples are
allowed to cool in air.

Which of the following is a CORRECT statement?

A The water will cool to a lower temperature.

B The ethanol will cool to a lower temperature.

C Both will result in the same temperature, but water will cool first.

D Both will result in at the same temperature, but ethanol will cool first.

User Yuro
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2 Answers

3 votes

Answer:

While both the ethanol and the water eventually will reach the same temperature, the ethanol will cool first. Thus, the correct answer is D.

Step-by-step explanation:

The specific heat capacity of a substance is the amount of heat energy required to raise the temperature of a unit mass of the substance by 1 °C. We're told that ethanol's specific heat capacity is 2.671 J/g °C and water's is 4.184 J/g °C.

Ethanol has a lower specific heat capacity than water. This means that for a given amount of energy, the temperature of a given mass of ethanol will increase by a greater amount than the same mass of water. Therefore, ethanol requires less energy to raise its temperature by 1 °C. Conversely, this also means that ethanol will lose heat at a faster rate than water; when ethanol and water are placed in a cooler environment, the ethanol will lose heat at a faster rate than the water and therefore cool down faster.

When energy is added to a substance, its temperature increases; when energy is removed from a substance, its temperature decreases. The change in a substance's temperature is inversely proportional to the substance's specific heat capacity. When both the ethanol and the water are placed in cooler surroundings, heat will flow from them to the environment until thermal equilibrium is reached. So, while both the ethanol and the water will eventually reach thermal equilibrium with their surroundings (i.e., they will both reach the same temperature at the end), ethanol will lose heat at a faster rate than water, and therefore it will cool down faster.

User Kaarto
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8.4k points
3 votes
C both will result in the same temperature but water will cool first
User Rpj
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7.9k points