$1.8 \ g$ of water is vaporized by supplying $4 \ kJ$ of heat at $100^{\circ}C$. What is the molar heat of vaporization of water at the same temperature?

$A$ swimmer coming out from a pool is covered with a film of water weighing about $18 \ g$. How much heat must be supplied to evaporate this water at $298 \ K$? Calculate the internal energy of vaporisation at $298 \ K$. Given: $\Delta_{vap} H^{\ominus}$ for water at $298 \ K = 44.01 \ kJ \ mol^{-1}$.

The enthalpy change on freezing of $1 \ mol$ of water at $5 \ ^\circ C$ to ice at $-5 \ ^\circ C$ is ..... $kJ \ mol^{-1}$.
(Given $\Delta _{fus}H = 6 \ kJ \ mol^{-1}$ at $0 \ ^\circ C$,
$C_p(H_2O, l) = 75.3 \ J \ mol^{-1} \ K^{-1}$,
$C_p(H_2O, s) = 36.8 \ J \ mol^{-1} \ K^{-1}$)

$A$ gas (Molar mass $= 280 \ g \ mol^{-1}$) was burnt in excess $O_2$ in a constant volume calorimeter and during combustion the temperature of calorimeter increased from $298.0 \ K$ to $298.45 \ K$. If the heat capacity of calorimeter is $2.5 \ kJ \ K^{-1}$ and enthalpy of combustion of gas is $9 \ kJ \ mol^{-1}$,then the amount of gas burnt is $...... \ g$. (Nearest Integer)

For the reaction $2Cl_{(s)} \to Cl_{2(s)}$,the signs of $\Delta H$ and $\Delta S$ respectively are

The ratio of heats liberated at $298 \ K$ from the combustion of one $kg$ of coke and by burning water gas obtained from $1 \ kg$ of coke is. (Assume coke to be $100 \%$ carbon.) (Given enthalpies of combustion of $CO_{2}, CO$ and $H_{2}$ as $393.5 \ kJ/mol, 283.5 \ kJ/mol, 285.5 \ kJ/mol$ respectively all at $298 \ K$.) (in $: 1$)