temperature Flashcards
definitions
heat
heat is a form of energy that can flow from one region to another
temperature
the temperature of a body is the physical quantity which indicates how cold or hot an object is.
heat transfer
when a hotter body is placed next to a colder body, thermal energy will flow from the hotter body to the colder body, this is known as heat transfer.
thermal contact
when a hotter body is placed in contact with a colder body , the bodies are said to be in thermal contact.
thermal equilibrium
when two objects in thermal contact , reach the same temperature and there is no net energy flow between them, the objects are in thermal equilibrium.
zeroth law of thermodynamics
this fundamental law states that if two bodies A and B are separately in thermal equilibrium with a third body C , then A and B are also in thermal equilibrium with each other.
fixed point
a fixed is a temperature where all thermometers show the same temperature
empirical scale of temperature
it is a temperature scale based on experimental values.
egs of empirical scale of temperature
resistance scale, thermoelectric scale , volume of liquid scale
effect of empirical scale of temperature
different thermometers give different reading, however all thermometers give same readings at fixed points
ice point
the ice point is the temp where ice and pure water are in equilibrium at standard atmospheric pressure.
steam point
the steam point is the temp where pure water and and its vapour are in equilibrium at standard atmospheric pressure.
numerical scale
it is the temperature interval between ice point and steam point
sensitivity
it is the distance moved by the mercury thread per 1° C increase in temperature.
thermodynamic scale of temperature
it is a scale of temp based on the properties of ideal gases.
unit = kelvin(K)
fixed points of thermodynamic
- absolute zero
- triple of water
absolute zero
it is the temperature at which no more energy can be removed from any object.
0K = -273.15° C
Triple point of water
the point where ice , water and water vapour are in equilibrium.
can be obtained by a triple point cell.
fixed as 273.16K
one kelvin
is defined as 1/273.16 x (temp of the triple point of water).
energy of molecules
even if a body/system/gas/liquid is at rest, its atoms move or vibrate like in a solid , so that each mole has microscopic Ek,
These atoms have interatomic forces which contribute to microscopic Ep
internal energy
It is the sum of randomly distributed Ep and Ek associated with the molecules in a system.
heat capacity
It is the qty of heat energy required to raise the temp of a body by 1°C or 1K
Specific heat capacity
SHC of a body is the amount of heat energy required to raise the temp of a unit mass of it by 1°C or 1K , without going through a change of state.
Q = mc▲T
Q=energy transferred in J
m=mass of water in g
c=SHC
T=temp ch
latent heat
the heat energy which changes the state of a substance.
latent heat of fusion definition
The energy needed to melt a solid at its melting point. OR
The energy needed to solidify a liquid at its at its freezing point.
specific latent heat of fusion
lf of a substance is defined as the amount of heat required to change the unit mass of the substance from solid to liquid state without changing its temp.
Q = m x lf
Q = amt of thermal energy absorbed or released (J)
m = mass of substance (kg)
lf = specific latent heat of fusion (j/kg)
specific latent heat of vaporization
lv of a substance is the amt of heat required to change the unit mass of the substance from liquid to gas state without changing its temp.
Q = m x lv
Q = amt of thermal energy absorbed or released (J)
m = mass of substance (kg)
lv = specific latent heat of vaporization
