How much energy is produced in the burning of $1\, kg$ of coal?

The density of a material $A$ is $1500 \ kg/m^3$ and that of another material $B$ is $2000 \ kg/m^3$. It is found that the heat capacity of $8$ volumes of $A$ is equal to the heat capacity of $12$ volumes of $B$. The ratio of specific heats of $A$ and $B$ will be

What is the total energy for one mole of a solid substance?

$A$ $10\, kW$ drilling machine is used to drill a bore in a small aluminium block of mass $8.0\, kg$. How much is the rise in temperature of the block in $2.5$ minutes,assuming $50\, \%$ of power is used up in heating the machine itself or lost to the surroundings? (Specific heat of aluminium $= 0.91\, J\, g^{-1}\, K^{-1}$)

The quantities of heat required to raise the temperatures of two copper spheres of radii $r_{1}$ and $r_{2}$ $(r_{1} = 1.5 r_{2})$ through $1 \ K$ are in the ratio of:

The temperature of $5$ moles of a gas which was held at constant volume was changed from $100^{\circ}C$ to $120^{\circ}C$. The change in internal energy was found to be $80$ Joules. The total heat capacity of the gas at constant volume will be equal to ...... $J/K$.