How do you calculate the average specific heat capacity of a solution?

Answer 1

Specific heat capacity of a gas is not fixed but varies as per experimental conditions.

Specific heat capacity( denoted as C usually) is heat required to increase the temperature of unit amount of substance through 1 unit( 10c or 1 K) in a given temperature scale.

So C = Q/(m*(T2-T1)) -----equation 1.

here Q = heat supplied

m = amount of substance in Kg or moles

T2-T1 = temperature rise.

For a gas Specific heat capacity(C) can be determined at constant pressure or constant volume(these two are important) or any other condition.

For all experimental processes or conditions equation 1 can be used

To determine C at constant pressure we should be given heat supplied(Q), mass or moles(m) of gas used and temperature change(T2-T1) and it should be mentioned that change took place in constant pressure. Then we can substitute values in equation 1 to find C at constant pressure( Cp)

Actually Regnault's apparatus is used to find Cp.

To determine C(denoted by Cv) at constant volume mentioned condition is that volume is constant and other steps are same as above.

Also if either Cp or Cv is given, for an ideal we can use Cp - Cv = R (take care of units on each,should be same), here R is the gas constant.

Also Cp or Cv can be found by application of thermodynamics.

Cp = dH/dT where H denotes enthalpy, T denotes temperature.

Cv = dU/dT where u denotes Internal energy.

Answer 2

u can calculate it by use of an equation of state . see "the properties of gases and liquids" chapter 6

Answer 3

You would add the values of the Solution from each Trial, then divide the total by the number of Trials done.