Does Mixing Fluids A and B Create a Predictable Thermal Capacity?

[pomekrank]

Hi,
Say we have fluid A with thermal capacity C_a and fluid B with C_b. If we create a solution with X% of fluid A and (1-X)% of fluid B, is it true that the new thermal capacity of the mixture will be
C_new ?= C_a*X + C_b * (1-X)
Or it is a case-by-case relationship that depends on the nature of the fluids ?

Thank you

 

[Bystander]

Case by case.

 

[Chestermiller]

Hi,
Say we have fluid A with thermal capacity C_a and fluid B with C_b. If we create a solution with X% of fluid A and (1-X)% of fluid B, is it true that the new thermal capacity of the mixture will be
C_new ?= C_a*X + C_b * (1-X)
Or it is a case-by-case relationship that depends on the nature of the fluids ?

Thank you

If A and B form a so-called "ideal solution," then your mixing rule is correct. For a solution to be ideal, the molecular attractions between A and A, B and B, and A and B must be nearly the same.