Thermal Properties of matter 1 Flashcards
what is temperature
it is the degree of hotness or coldness of a body
what is heat
heat is the
form of energy transferred between two (or
more) systems or a system and its
surroundings by virtue of temperature
difference.
what is boyle’s law and charles law
When temperature
is held constant, the pressure and volume of a
quantity of gas are related as PV = constant.
This relationship is known as Boyle’s law, after
Robert Boyle (1627-1691) the English Chemist
who discovered it. When the pressure is held
constant, the volume of a quantity of the gas is
related to the temperature as V/T = constant.
This relationship is known as Charles’ law
what does each thermometer have
it has 2 fixed points called the upper fixed point and lower fixed point.
ufp: boiling point/ steam point
lfp: melting/freezing point/ icoe point
what is thermal expansion
The increase
in the dimensions of a body due to the increase
in its temperature is called thermal expansion.
The expansion in length is called linear
expansion. The expansion in area is called area
expansion. The expansion in volume is called
volume expansion
what is the anomalous behaviour of water
Water exhibits an anomalous behavour; it
contracts on heating between 0 °C and 4 °C.
The volume of a given amount of water decreases
as it is cooled from room temperature, until its
temperature reaches 4 °C, [Fig. 11.7(a)]. Below
4 °C, the volume increases, and therefore the
density decreases.This means that water has a maximum
density at 4 °C
how do marine life survive in cool temperature
Bodies of water, as in lakes and ponds, freeze at the top first. As a
lake cools toward 4 °C, water near the surface
loses energy to the atmosphere, becomes denser,
and sinks; the warmer, less dense water near
the bottom rises. However, once the colder water
on top reaches temperature below 4 °C, it
becomes less dense and remains at the surface,
where it freezes. If water did not have this
property, lakes and ponds would freeze from the
bottom up, which would destroy much of their
animal and plant life
dependence of coefficient of expansion of temperature
coefficient of linear expansion of solids is a charcateristic property of a material but not necessarily a constant. it increases with temperature. it becomes a constant at higher temperature.
For liquids, the
coefficient of volume expansion is relatively
independent of the temperature. However, for
gases it is dependent on temperature. For an
ideal gas, the coefficient of volume expansion at
constant pressure can be found from the ideal
gas equation.
it is inversly proportional to temperature/
what is thermal stress
when a metal rod whose both ends are fixed so as to prevent it from expansion or contraction undergoes a temperature change., thermal stress and strain is developed.
what is heat capacity
the amount of heat required to raise the temperature of the whole substance by 1K
what is specific heat capacity
the amount of heat required to raise the temperature of unit mass of substance by 1K
what is molar specific heat capacity
the amount of heat required to raise the temperature of 1 mole of substance by 1K
applications of water due to high specific heat capcptiy
Water has the highest specific heat capacity compared
to other substances. For this reason water is
used as a coolant in automobile radiators as well
as a heater in hot water bags. Owing to its high
specific heat capacity, the water warms up much
more slowly than the land during summer and
consequently wind from the sea has a cooling
effect.
what happens during change of state
both the solid
and liquid states of the substance coexist in
thermal equilibrium during the change of
states from solid to liquid. It is observed that the temperature
remains constant until the entire amount of the
solid substance melts.
what is melting and melting point
the change of state from solid to liquid is called as melting and from liquid to oslid is called fusion.
The temperature
at which the solid and the liquid states of the
substance in thermal equilibrium with each
other is called its melting point.
The melting point of a substance
at standard atomspheric pressure is called its
normal melting point.
