The heat provided by the heater is given by the equation:

$Q = \text{Power} \times \text{Time}$

Substituting the given values:

$Q = 60 \, \text{W} \times 100 \, \text{s} = 6000 \, \text{J}$

The heat capacity (C) is defined as the amount of heat required to raise the temperature of a substance by one degree. It is given by the equation:

$C = Q/\Delta T$

Substituting the given values:

$C = 6000 \, \text{J} / 5 \, \text{°C} = 1200 \, \text{J/K}$

So, the heat capacity of the given gas is approximately 1200 J/K.