The mass of a monoatomic gas can be computed from its specific heat at constant volume cv. (note that this is not cv.) take cv = 0.075 cal/g · c° for a gas and calculate (a) the mass of its atom and (b) the molar mass.

a)

b) 39.74 g/mol

Explanation:

We have specific heat at constant volume cal/g if the monoatomic gas behaves as ideal gas, we can know the molar specific heat at constant volume . For a monoatomical gas with R the universal gas constant. So . We can calculate the heat with or as follows with m: mass and n: number of moles. So we can solve that equation for the molar mass (M=m/n) obtaining . We can answer the question b) M=2.9805/0.075=39.74 g/molWith the molar mass and the avogadro's number ( we can calculate the atom mass as follows Answer for the question a) is   

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