# Helpp with thermodynamics and specific heat question!

For an ideal monatomic gas, the molar specific heat at constant volume,
Cv=3/2R, where R is the gas constant. The heat capacity at constant volume of a gas is measured to be 43.58kJK-1. How many kg-moles of the gas are present?

Iv tried looking in the lecture notes and in the textbook, but cant find anything of use.

Iv made an attempt and got 3.5kg-moles. Not sure that its right though. I used R=kNA, where k is Boltzmann constant and NA is Avogadros number.

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Andrew Mason
Homework Helper
For an ideal monatomic gas, the molar specific heat at constant volume,
Cv=3/2R, where R is the gas constant. The heat capacity at constant volume of a gas is measured to be 43.58kJK-1. How many kg-moles of the gas are present?

Iv tried looking in the lecture notes and in the textbook, but cant find anything of use.

Iv made an attempt and got 3.5kg-moles. Not sure that its right though. I used R=kNA, where k is Boltzmann constant and NA is Avogadros number.
The heat capacity of n moles is n times the molar heat capacity.

The heat capacity of one mole of gas at constant volume is that amount heat flow required to raise the temperature one degree:

$$C_v = Q/\Delta T$$

If there are n moles, multiply both sides by n to determine the amount of heat flow per degree of temperature change.

AM