How Much Heat Is Transferred When 25.0 Grams Of Ethyl Alcohol At 68°C Is Cooled To Room Temperature (22°C)? Is The Energy Absorbed Or Released?
Introduction
When a substance undergoes a change in temperature, it either absorbs or releases heat energy. In this scenario, we are interested in determining the amount of heat transferred when 25.0 grams of ethyl alcohol at 68°C is cooled to room temperature (22°C). To solve this problem, we will employ the principles of heat transfer and energy changes.
Understanding Heat Transfer
Heat transfer occurs when there is a temperature difference between two systems. In this case, the ethyl alcohol is initially at a higher temperature (68°C) than the room temperature (22°C). As the ethyl alcohol cools down, it will release heat energy to the surroundings. This process is an example of heat transfer from a higher temperature system to a lower temperature system.
Specific Heat Capacity of Ethyl Alcohol
To calculate the amount of heat transferred, we need to know the specific heat capacity of ethyl alcohol. The specific heat capacity is the amount of heat energy required to raise the temperature of a unit mass of a substance by one degree Celsius. The specific heat capacity of ethyl alcohol is approximately 2.44 J/g°C.
Calculating Heat Transfer
We can use the formula for heat transfer to calculate the amount of heat transferred:
Q = mcΔT
Where:
- Q is the amount of heat transferred
- m is the mass of the substance (25.0 grams in this case)
- c is the specific heat capacity of the substance (2.44 J/g°C for ethyl alcohol)
- ΔT is the change in temperature (68°C - 22°C = 46°C)
Plugging in the values, we get:
Q = (25.0 g) × (2.44 J/g°C) × (46°C)
Q = 2832.8 J
Energy Absorbed or Released
Since the ethyl alcohol is cooling down, it will release heat energy to the surroundings. Therefore, the energy change is negative, indicating that the ethyl alcohol releases heat energy.
Conclusion
In conclusion, when 25.0 grams of ethyl alcohol at 68°C is cooled to room temperature (22°C), the amount of heat transferred is approximately 2832.8 J. The energy change is negative, indicating that the ethyl alcohol releases heat energy to the surroundings.
Applications of Heat Transfer
Heat transfer is an essential concept in various fields, including chemistry, physics, and engineering. Understanding heat transfer is crucial in designing systems that involve temperature changes, such as refrigeration systems, heat exchangers, and thermal energy storage systems.
Real-World Examples
Heat transfer is all around us, and we encounter it in our daily lives. For example, when you take a hot shower, the water releases heat energy to the air, causing the air to warm up. Similarly, when you leave a hot cup of coffee on a cold surface, the coffee releases heat energy to the surroundings, causing the coffee to cool down.
Importance of Heat Transfer
Heat transfer is an essential process that occurs in various natural and industrial systems. Understanding heat transfer is crucial in designing systems that involve temperature changes, such as refrigeration systems, heat exchangers, and thermal energy storage systems.
Future Research Directions
Future research directions in heat transfer include developing more efficient heat transfer systems, understanding the effects of heat transfer on the environment, and exploring new applications of heat transfer in various fields.
Conclusion
In conclusion, heat transfer is an essential concept in chemistry and physics that involves the transfer of energy from one system to another due to a temperature difference. Understanding heat transfer is crucial in designing systems that involve temperature changes, such as refrigeration systems, heat exchangers, and thermal energy storage systems.
Q: What is heat transfer?
A: Heat transfer is the process by which energy is transferred from one system to another due to a temperature difference. In the case of ethyl alcohol cooling, heat transfer occurs from the ethyl alcohol to the surroundings.
Q: What is the specific heat capacity of ethyl alcohol?
A: The specific heat capacity of ethyl alcohol is approximately 2.44 J/g°C. This means that it takes 2.44 joules of energy to raise the temperature of 1 gram of ethyl alcohol by 1 degree Celsius.
Q: How do you calculate the amount of heat transferred?
A: To calculate the amount of heat transferred, you can use the formula:
Q = mcΔT
Where:
- Q is the amount of heat transferred
- m is the mass of the substance (25.0 grams in this case)
- c is the specific heat capacity of the substance (2.44 J/g°C for ethyl alcohol)
- ΔT is the change in temperature (68°C - 22°C = 46°C)
Q: Is the energy change positive or negative?
A: Since the ethyl alcohol is cooling down, it will release heat energy to the surroundings. Therefore, the energy change is negative, indicating that the ethyl alcohol releases heat energy.
Q: What are some real-world examples of heat transfer?
A: Heat transfer is all around us, and we encounter it in our daily lives. For example:
- When you take a hot shower, the water releases heat energy to the air, causing the air to warm up.
- When you leave a hot cup of coffee on a cold surface, the coffee releases heat energy to the surroundings, causing the coffee to cool down.
- When you drive a car, the engine releases heat energy to the surroundings, causing the air to warm up.
Q: Why is heat transfer important?
A: Heat transfer is an essential process that occurs in various natural and industrial systems. Understanding heat transfer is crucial in designing systems that involve temperature changes, such as refrigeration systems, heat exchangers, and thermal energy storage systems.
Q: What are some future research directions in heat transfer?
A: Future research directions in heat transfer include:
- Developing more efficient heat transfer systems
- Understanding the effects of heat transfer on the environment
- Exploring new applications of heat transfer in various fields
Q: Can heat transfer be used to generate electricity?
A: Yes, heat transfer can be used to generate electricity. For example, in a steam turbine, heat energy is transferred from a high-temperature source to a low-temperature sink, causing the steam to expand and drive a turbine, which generates electricity.
Q: Can heat transfer be used to cool buildings?
A: Yes, heat transfer can be used to cool buildings. For example, in a heat exchanger, heat energy is transferred from a hot fluid to a cold fluid, causing the hot fluid to cool down and the cold fluid to warm up.
Q: What are some common applications of heat transfer?
A: Some common applications of heat transfer include:
- Refrigeration systems
- Heat exchangers
- Thermal energy storage systems
- Power generation systems
- Building cooling systems
Q: Can heat transfer be used to improve energy efficiency?
A: Yes, heat transfer can be used to improve energy efficiency. For example, in a heat exchanger, heat energy is transferred from a hot fluid to a cold fluid, causing the hot fluid to cool down and the cold fluid to warm up, which can improve the overall efficiency of the system.