PHYSICS: THERMODYNAMICS Flashcards
Atoms
-all matter is made up of atoms
-smallest particles of an element that retains all the chemical properties of the element
Kinetic theory of matter
-states that atom and matter are in a constant state of motion
-the motion and spacing of atoms determine the state of simple matter
-the three ordinary states of matter are solid liquid and gas
-when matter is in the gas or liquid state, molecules, which are groups of atoms, are free to move around
-gases and liquids do not have definite shapes, when a liquid or gas is placed in a container the atoms or molecules move around freely in the container and take a shape
-these molecules move in all possible directions and keep colliding with the walls of the container
-each time a molecule collides with the wall it delivers an impulse to the wall
-the greater the quantity of gas or liquid in a container, the more frequent collisions are
Pressure
The result of the impulses from the collision of molecules with the walls of the container
[two important laws of thermodynamics]
Boyle’s law
-states that the volume of a fixed amount of gas varies inversely with the pressure of the gas
-if the volume of the gas is decreased, both the number of particle collisions and the pressure of the gas increase
-if the volume of the gas is increased, the pressure of the gas decreases
- V^P,, P^V,, FOR GAS
[two important laws of thermodynamics]
CHARLES’ LAW
-defined the relationship between the temperature and volume of a gas
-according to this law, the volume of a fixed amount of gas varies directly with its temperature (if pressure of gas is constant)
-if the temperature of gas increases the volume increases
-T^V^, V^T^
Temperature
-measure of the average kinetic energy of the particles in a substance
-tells how warm or cold a substance is with respect to other substances
-determines whether a substance gains or gives up heat when put into contact with other bodies
Heat
-form of energy that causes the particles of matter to move faster and farther apart
-when a substance is heated, temperature increases
Specific heat
The heat needed to raise the temperature of 1 gram of a substance by 1° Celsius
Phase change
-refers to the physical change of a substance from one state to another example ice when it melts
-when the temperature of a substance changes, its phase may change
Latent change
The heat energy needed per unit mass to change the phase of a substance
Temperature is measured with a thermometer using different scales
-most commonly used temperature scale is the Celsius scale
-two other scales are the Fahrenheit scale and the kelvin, or absolute temperature, scale
-ice point is the temperature at which ice melts or water freezes
-on the Fahrenheit scale, the ice point is 32° on the Celsius scale the ice point is 0°
-the steam point is the point at which water at standard pressure boils
-on the Celsius scale the steam point is 100°: it is 212° on the Fahrenheit scale
-the triple point (273.16 kelvins) on the kelvin scale is the temperature at which water exist simultaneously as a gas, liquid, and the solid
-on the kelvin scale the lowest possible temperature is known as absolute zero, or zero Kelvin (0 K)
Relationship of the kelvin to the Celsius scale
