The heat evolved in the combustion of methane is given by the following equation: $CH_{4(g)} + 2O_{2(g)} \to CO_{2(g)} + 2H_2O_{(l)}$; $\Delta H = -890.3 \ kJ$. How many grams of methane would be required to produce $445.15 \ kJ$ of heat of combustion?

Which one of the following is always not negative?

The quantity of heat (in $J$) required to raise the temperature of $1.0 \, kg$ of ethanol from $293.45 \, K$ to the boiling point and then change the liquid to vapor at that temperature is closest to
[Given,boiling point of ethanol $351.45 \, K$. Specific heat capacity of liquid ethanol $2.44 \, J \, g^{-1} \, K^{-1}$. Latent heat of vaporisation of ethanol $855 \, J \, g^{-1}$ ]

For a reaction,$X_{2(g)} + Y_{2(g)} \rightleftharpoons 2XY_{(g)}$. If $\Delta G_r^o = 20 \ kJ \ mol^{-1}$ and $\Delta S_r^o = -20 \ J \ K^{-1} \ mol^{-1}$ at $200 \ K$. Calculate $\Delta H_r^o$ at $400 \ K$ (Given $\Delta_r C_P = 20 \ J \ K^{-1} \ mol^{-1}$).

The oxidising power of chlorine in an aqueous solution can be determined by the parameters indicated below:
$\frac{1}{2} Cl_{2(g)} \xrightarrow{\frac{1}{2} \Delta_{diss} H^{\Theta}} Cl_{(g)} \xrightarrow{\Delta_{eg} H^{\Theta}} Cl^{-}_{(g)} \xrightarrow{\Delta_{Hyd} H^{\Theta}} Cl^{-}_{(aq)}$
(Using the data: $\Delta_{diss} H_{Cl_2}^{\Theta} = 240 \ kJ \ mol^{-1}$, $\Delta_{eg} H_{Cl}^{\Theta} = -349 \ kJ \ mol^{-1}$, $\Delta_{Hyd} H_{Cl}^{\Theta} = -381 \ kJ \ mol^{-1}$), the total enthalpy change $\Delta H$ will be ............. $kJ \ mol^{-1}$.

Which of the following statements is incorrect?