Workbook 3 Flashcards
What is Internal Energy?
The Internal Energy is the sum of the Kinetic energy and Potential energy in a system.
What is the relationship between internal energy and temperature?
The higher the internal energy per atom of an object, the higher the temperature.
Define temperature
Temperature is a measure of the degree of hotness of a body.
State the zeroth law of Thermodynamics
The Zeroth Law of thermodynamics states that if a body A, is in thermal equilibrium with a body B, and the body B is in thermal equilibrium with a body C, then bodies A and C are in thermal equilibrium with one another.
Define heat energy.
Heat energy is defined as being the energy in transit from one object to another.
What is thermal contact?
Thermal contact refers to two objects in a system where energy is being transferred from one to another through the process of heat.
State the first law of thermodynamics
The first Law of Thermodynamics states that any change in internal energy of a system can be caused by supplying/taking away heat energy to/from the system and/or by work done on/by the system.
How can energy be transferred?
By supplying heat energy, mechanically doing work and electrically (force exerted due to charges)
Define Heat Capacity
Heat Capacity of a body is defined as being the amount of heat required to raise the temperature of a body by 1 degree Celsius or 1 Kelvin.
Define Specific Heat Capacity
Specific Heat Capacity of an object is defined as being the amount of heat energy needed to raise the temperature of 1kg of a material by 1 degree Celsius or 1 Kelvin.
Define Latent Heat
Latent Heat is defined as the amount of heat energy supplied to a material to cause a change in state without causing a change in temperature.
Distinguish between Latent heat of fusion and Latent heat of vaporisation,
The Latent heat needed to change the state of a solid to a liquid is called the latent heat of fusion, whilst that needed to change the state from liquid to gas is referred to latent heat of vaporisation.
Define Specific Latent Heat
Specific Latent Heat of a substance is defined as the energy required to cause a change in state in 1kg of a substance without causing a change in temperature.
What is a thermometric property?
A thermometric property is a physical property that changes in a known way with temperature, and therefore can be used to measure temperature.
What is an ideal gas?
It is a gas that does not exist, whose molecules occupy negligible space and have no interaction with each other and that obeys the gas laws exactly.
State Boyle’s Law
Boyle’s Law states that for a fixed amount of gas, at constant temperature, the product of pressure and volume is a constant.
State Charles’ Law
Charles’ Law states that for a fixed amount of gas, at constant pressure, the volume is directly proportional to the temperature when measured in Kelvins.
State the Pressure/Gay Lussac’s Law
The Pressure Law states that for a fixed amount of gas, at constant volume, the pressure is directly proportional to the temperature when measured in Kelvin.
What is special about an ideal gas?
Its internal energy is entirely kinetic and depends only on its temperature. It is low pressure: very few collisions and little effect of electrostatic forces. Its temperature is larger than boiling point so that most of the internal energy will end up being kinetic rendering PE to be an even smaller fraction of total U.
Describe the Kinetic Theory
It states that a gas consists of a large number of molecules moving randomly at high average speeds. Collisions of these molecules with the sides of a container gives rise to pressure.
State the assumptions for the Kinetic Theory of Gases equation.
- A gas consists of a large number of molecules.
- These molecules move about randomly.
- Collisions between the molecules and the container are perfectly elastic.
- The forces of attraction between the molecules are negligible.
- The time of contact of the molecule with the sides of the container is negligible when compared to the time between collisions.
- The volume of the molecules themselves is negligible when compared to the volume of the container they are in.
Describe Brownian Motion
Brownian motion is a jerky, random, straight-line motion interrupted by collisions with other particles or with a physical boundary.
Why is the Root-Mean-Square used for velocities of gaseous particles?
This is because since velocity is a vector quantity, it can be both a positive and negative quantity. When trying to take the mean, this could equal zero, therefore to properly assess the average velocity, we take the average of the square and then square root the value.
Define the molar heat capacity of a substance.
The molar heat capacity of a substance is defined as being the heat energy required to produce a unit temperature rise in 1 mole of a substance.