Manipal Entrance Test 2015 Physics Paper

Molar specific heat = Molecular weight × gram specific heat.
CV=M×cV
2.98 cal/mol-K = M × 0.075 kcal/kg-K
=

M×0.075×103

103

‌cal∕g−K
∴ Molecular weight of argon,
M=

2.98

0.075

=39.7g
i.e. mass of 6.023×1023 atom =39.7g
Therefore, mass of single atom =

39.7

6.023×1023

=6.60×10−23g