3. Temperature A.md
2024-4-11|2024-4-12
Pat
type
status
date
slug
summary
tags
category
icon
password
Thermal Equilibrium
- Understanding: What happens to thermal energy when it is transferred from a region of higher temperature to a region of lower temperature? Answer: When thermal energy is transferred from a region of higher temperature to a region of lower temperature, the higher temperature region cools down and the lower temperature region warms up. This transfer continues until both regions reach the same temperature, at which point they are in thermal equilibrium.
- Understanding: What is meant by thermal equilibrium? Answer: Thermal equilibrium is a state in which all parts of a system are at the same temperature. In this state, no heat flows from one part of the system to another, indicating that the system has reached a balanced state of energy distribution.
Temperature Scales
- Understanding: What kind of physical properties that vary with temperature can be used for the measurement of temperature? Can you state examples of such properties? Answer: Physical properties that vary with temperature and can be used for the measurement of temperature include the density of a liquid, the volume of a gas at constant pressure, the resistance of a metal, and the electromotive force of a thermocouple.
- Understanding: Why does the scale of thermodynamic temperature not depend on the property of any particular substance? Answer: The scale of thermodynamic temperature does not depend on the property of any particular substance because it is based on the absolute zero point, the temperature at which all molecular motion ceases. This is a universal property, not dependent on any specific substance.
- Conversion: Convert a temperature of 25°C into kelvins. Answer: The conversion between Celsius and Kelvin is given by T(K) = θ(°C) + 273.15. So, a temperature of 25°C is equivalent to 25 + 273.15 = 298.15 K.
- Understanding: What is the lowest possible temperature on the thermodynamic temperature scale and what is it known as? Answer: The lowest possible temperature on the thermodynamic temperature scale is zero kelvin. This is known as absolute zero and represents a state of minimum thermal energy where all molecular motion theoretically ceases.
Specific Heat Capacity and Specific Latent Heat
- Definition and Use: Define specific heat capacity and use it to calculate the heat required to raise the temperature of 2 kg of water by 5°C. The specific heat capacity of water is 4186 J/kg°C. Answer: Specific heat capacity is the amount of heat energy required to raise the temperature of one kilogram of a substance by one degree Celsius. The heat required can be calculated using the formula Q = mcΔT, where m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. For 2 kg of water with a change in temperature of 5°C, the heat required is Q = 2 kg 4186 J/kg°C 5°C = 41860 J.
- Definition and Use: Define specific latent heat and distinguish between specific latent heat of fusion and specific latent heat of vaporisation. Answer: Specific latent heat is the amount of heat energy required to change the phase of one kilogram of a substance without changing its temperature. The specific latent heat of fusion is the heat energy required to change a substance from solid to liquid at its melting point per unit of mass, while the specific latent heat of vaporisation is the heat energy required to change a substance from liquid to gas (or vice versa) at its boiling point.
Loading...