Term 1 Exam Flashcards
(33 cards)
Define Thermodynamics.
The study of the relationship between thermal energy, heat, and work.
Define an open system.
A system in which matter can enter from or escape to the surroundings.
Define a closed system.
Matter is not allowed to enter or leave but heat can.
Define an isolated system.
A system that exchanges neither matter nor energy with its surroundings.
What does the basic atomic structure consist of?
Protons, Neutrons and Electrons.
What is internal energy and its symbol?
The sum of the total kinetic and potential energies.
The symbol is U
Define Temperature
A measure of the average kinetic energy.
What is absolute zero?
The temperature at which no more energy can be removed from matter.
What is the temperature in Kelvin for absolute zero/freezing point?
-273.15K
What is the formula to work out the average kinetic energy?
3/2(1.38x10-23) x temperature in kelvin
State the 0th law of thermodynamics.
When two objects come into contact, heat flows from the body of the higher temperature to the one of lower temperature
What is thermal equilibrium?
When two objects have the same temperature and there is no net heat flow.
How do we convert Kelvin to celcius?
Subtract 273.15
Define heat and what it does.
The energy transferred between objects that are at different temperatures.
Increases Kinetic energy which creates a higher temperature and increases potential energy making change of bonds.
What is calories in joules?
4.185J
What is BTU in joules?
1054J
What is the 1st law of thermodynamics?
Energy cannot be created or destroyed. It can only change form.
What does the change of temperature depend on?
The amount of heat added and the type of substance added.
Define specific heat capacity.
A measure of the ability of a material to absorb heat or the amount of energy required to raise the temperature of 1kg of a substance by 1K
What is the equation to work out the Specific heat capacity of an object?
DeltaQ = m x c x temperature change.
Define latent heat and what happens in phase change?
The amount of heat required to change the state of one unit of mass of a substance without any change of its temperature.
During phase change, the heat is only ALTERING THE POTENTIAL ENERGY by changing interactions between particles.
What are the 3 types of latent heat?
Latent heat of fusion or solidification - the amount of heat needed to melt a unit of mass of a substance from solid to liquid. (vice versa)
Latent heat of vaporisation or condensation - the amount of heat needed to vaporise a unit of mass of a substance from liquid to gas (vice versa)
Latent heat of sublimation or deposition - the amount of heat needed to vaporise a unit of mass of a substance from solid to gas (vice versa)
Define electricity
Created by the flow of electrons usually between atoms of metallic elements.
Define current including the symbol and unit.
When there is a voltage difference between two points in a circuit, electrons move along the wire creating flow of electrons
Symbol: I
Units: A (amperes)
