Why does gas have two principal specific heat capacities while solids and liquids have only one?
we have two principle specific heats of a gas, one at constant pressure and another at constant volume. When heat is supplied to a solid or liquid, there is negligble expansion of the solid or liquid. That is why there is only one value of specific heat of solid or liquid which is at constant volume.
Why do we define two specific heats specific heat capacity at constant volume and specific heat capacity at constant pressure?
When gas is heated at a constant pressure, it expands, and gas has to do work against the external pressure. Therefore, in addition to the heat which is required to raise the temperature, heat is also required to expand the gas. So, at constant pressure, we require more heat than at constant volume.
Why does a gas not possesses a unique or single specific heat?
This is because a gas can be heated under different conditions of pressure and volume. The amount of heat required to raise the temperature of unit mass through unit degree is different under different conditions of heating.
What is relation between CP and CV?
The specific heat of gas at constant volume in terms of degree of freedom ‘f’ is given as: Cv = (f/2) R. Also, Cp – Cv = R. Therefore, Cp = (f/2) R + R =R (1 + f/2)
Which specific heat of a gas is greater Why?
Explanation of Cp is greater that Cv : When a gas is heated at a constant pressure, it expands. The heat supplied to it is used partly in raising its temperature and partly in doing work against the external pressure. If, on the other hand, the gas is heated at constant volume, no work is done.
Why is specific heat capacity important?
Specific heat capacity is a measure of the amount of heat energy required to change the temperature of 1 kg of a material by 1 K. Hence it is important as it will give an indication of how much energy will be required to heat or cool an object of a given mass by a given amount.
What does specific heat of a gas possess?
For the gases, the temperature is increased by either constant volume and constant pressure, known as Cp and Cv. Hence, gases have Cp and Cv. Also in case of solid, the values of Cp and Cv remains almost same, hence solid has only one specific heat.
Why does CP exceed CV for an ideal gas?
Cp is greater than the molar specific heat at constant volume Cv because energy must now be supplied not only to raise the temperature of the gas but also for the gas to do work. More heat would be required at constant pressure to cause the same temperature rise and Cp will be greater than Cv.
What is the relation between the two specific heats of a gas which is greater and why?
specific heat at constant pressure is more than the specific heat at constant volume because the gas can expand in the first case, causing more absorption of heat as compared to other one..
What is specific heat of a gas?
The specific heat of a gas at constant pressure is the amount of heat required to raise the temperature of one mole of a gas by unit temperature at constant pressure.
Why is specific heat capacity more useful than heat capacity?
Meanwhile, specific heat capacity is an intensive property because it does not matter the amount of substance present. For example in lecture, the heat capacity was 49 kj/c while the specific heat capacity is j/k × mol. The specific heat capacity is more useful in calculations because it is an intensive property.
Why do we define two specific heats of gases?
Hence it is necessary to define two specific heats of gases. viz. Specific heat at constant pressure and specific heat at constant volume. The quantity of heat required to raise the temperature of one mole of gas through 1K (or 1 °C) when the volume is kept constant is called molar specific heat at constant volume. It is denoted by C V.
What is principal specific heat at constant volume?
The quantity of heat required to raise the temperature of a unit mass of gas through 1 K (or 1 °C) when its volume is kept constant, is called its principal specific heat at constant volume. It is denoted by c V. Its S.I. unit is J K -1 kg -1.
What is heat capacity of a gas?
Gases have two kinds of heat capicities. one for at constant pressure called as heat capacity at constant pressure. in this kind of heat capacity work is done by system because the volume of the gas increases.
What is the difference between heat capacity ratio and specific heat?
Heat capacity ratio is defined for compressible substances coz only compressible substances have two specific heats Cp (heat capacity at constant pressure) and CV (heat capacity constant volume). For in compressible substances we have only single specific heat