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Flashcards in 2. Thermal Physics Deck (29)
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Describe solid

Strong forces of attraction between particles
Have fixed pattern
Atoms vibrate but can't change position


Describe liquid

Weaker attractive force than solid
No fixed pattern
Particles slide past each other


Describe gas

Almost no intermolecular force
Particles are far apart, move quickly
Gases spread out to fill up the container and exert equal pressure on all surfaces
Collide with each other and bounce in all direction


What is pressure of gas

Due to particles colliding on the container wall


Describe brownian motion

Smoke particles appear to be in random motion
This is bc they are constantly being hit by other rapidly moving particles in the air
This is a evidence that particles in air are in constant random motion
Massive particles may be moved by light, fast moving particles


Describe evaporation

The transformation of liquid into a gas at a temperature below the boiling point of the liquid
Particles with more kinetic energy move faster and overcome the force of attraction between the molecules and escape from the surface
Constantly occur on the surface of the liquid


Relate evaporation to cooling

More energetic particles escape, the liquid contains fewer high energy particles and more lower energy particles so the average temperature decrease


Describe the factors affecting evaporation

More surface area, higher temperature and blow air across the surface increase evaporation


Describe Boyle's law

When temperature is constant, pressure x volume = constant


Describe the the al expansion of liquid gas and solid

Liquid expand -> increase volume
Gas expand at constant volume -> higher pressure, at constant pressure -> higher volume
Gas > liquid > solid


What is fixed point

Use to define a scale of temperature
Fix points are definite temperature at which sth happen
Ice point : 0c - pure ice melt
Steam point : 100c pure water boil


What is thermometric property of the thermometer

The physical property that varies with temperature


Describe the liquid in glass thermometer

Consists of a thin glass bulb joined to a capillary tube
The liquid fills the bulb and the tube
When the bulb become warmer, liquid expand and the liquid in the bulb is forced into the capillary tube
The amount of expansion can be matched to a temperature on the scale
Use in home, office, greenhouse and hospital


What is range

The lowest and highest temperature of the thermometer


What is sensitivity

The extent of change in the thermometric property for a 1c rise of temperature


What is linearity

Extent of difference between each individual degrees
Higher difference, poorer linearity


What is thermal capacity

The energy that must be supplied to an object to raise its temperature by 1c


How to calculate thermal capacity?

Energy / change in temperature


What is specific heat capacity

The energy needed to raise the temperature of 1kg of the substance by 1c
Unit J/(kg c)


How to calculate specific heat capacity

Energy / mass x change in temperature


What is melting point

The temperature at which it melts or solidify


What is boiling point

The temperature at which it boils or condenses


What is latent heat

The energy supplied to a substance when it changes its state without changing temperature


What is latent heat of fusion

The energy supplied for a substance to melts and turns to liquid
E energy used by molecules to break free from each other


What is latent heat of vaporization

The energy supplied for a substance to vaporize and is used by the molecules to break away from the liquid


What is the specific latent heat of fusion

The energy needed to melt 1kg of the substance at its melting point


What is the specific latent heat of vaporization

The energy needed too change 1kg of the substance at its boiling point from liquid - vapor


How to calculate the specific latent heat

Energy / mass
Unit J/kg


Why metal conducts heat

Metal contain a lot of conduction electrons
When it is heated, the free electrons at the hot end gain ke and move fast -> transfer ke to electrons and ions