Thermal physics Flashcards
(20 cards)
What is the Kinetic theory?
- All matter is made up of particles and are in constant motion
- The particles are attracted to each other and held together by intermolecular forces
- The higher the temperature the faster they move, so the more kinetic enery they contain.
What is heat?
The trasnfer of thermal energy between molecules and is measured in Joules
What is temperature?
The average kinetic energy in a material or system and its measured in Kelvin or celcius
What is the connection between temperature and heat?
Heat is the transfer of thermal energy that is caused by the difference in temperature between molecules
What happens when heat is added to an object?
-The average kinetic energyy of the atoms will increase
- the temperature will increase
- the object will expand
The state of matter may change
A change in temperature can affect the objects….
size
pressure
state of matter
solubility
What is a lab thermometer?
A liquid in gas thermometer
It holds liquid in the bulb
when placed in a substance, the liquid will exapand or contract based on the temperature of the substance
contract when its cooled
expand when it heated
range: -10 degrees to 110 degrees
What is the clinial thermometer?
- used to measure the body temperature of humans.
- ranges from 35 degrees to 42 degrees
- based on the expansion of mercury
- when placed under the tongue or armpit the body temperature causes the mercury to expand and rise up in the capillary tube to indicate the temperature.
What is the thermocouple?
- consists of two wires of different temperature
- when the end wire is exposed to a temperature it causes a pd differnce between them which gives the temperature.
It ranges between 95 and 1600 degrees - it uses a change in potential difference to indicate the temperature
Explain boyles law
- At a constant temperature the volume of a fixed mass of gas varies indirectly to the pressure.
- As the volume decreases the particles have less space to move around so they hit the walls of the container more frequently, thus increasing the pressure.
p1v1=p2v2
Explain charles law
-At a constant pressure, the volume of a given amount of gas is directly proportional to the kelvin temperature .
- As the temperature increases the particles gain kinetic energy and move faster. For pressure to remain constant, the volume has to increase.
v1/t1=v2/t2
Explain the pressure law
- At a constant volume, the pressure of a gas is directly proportional to the kelvin temperature.
p1/t1=p2/t2
What is the general gas law?
p1v1/t1=p1v2/t2
- The volume of a gas is proportional to the ratio of its temperature and pressure.
What is heat capacity?
Give the formula,symbol and unit
- The amount of heat energy needed to raise the temperature of a substance by 1 kelvin or degree celcius
- heat energy/temperature change
- J/k or Jk-1
symbol- C
What is specific heat capacity?
Give formula,symbol and unit
The amount of heat energy needed to raise 1kg a substance by 1 kelvin or degree celcius
- heat energy/mass x change in temperature
- Jkg-1k-1
symbol- c
What’s an alternative formula for finding heat capacity?
C=mc
What is latent heat?
The heat energy needed to change the phase or state of an object without temperature change.
What is the specific latent heat of fusion?
The latent heat of fusion of a solid substance is the amount of heat energy needed to change 1kg of the substance from solid to liquid wihout a change in temperature.
What is the specific latent heat of vapourisation?
The specific latent heat of vapourisation of a liquid substance is the amount of heat energy needed to change 1kf of the substance from liquid to gas without a change in temperature.
