The heat of atomization of methane and ethane are $360 \ kJ/mol$ and $620 \ kJ/mol,$ respectively. The longest wavelength of light capable of breaking the $C-C$ bond is (Avogadro number $= 6.02 \times 10^{23},$ $h = 6.62 \times 10^{-34} \ J \cdot s$)

If $38.55 \ kJ$ of heat is absorbed when $6.0 \ g$ of $O_2$ reacts with $ClF$ according to the reaction $2ClF_{(g)} + O_{2(g)} \longrightarrow Cl_2O_{(g)} + OF_{2(g)}$. What is the standard enthalpy of reaction (in $kJ$)?

At $298 \ K$,the enthalpy change (in $kJ$) for the reaction given below is: $CH_{4(g)} + O_{2(g)} \rightarrow C_{(s)} + 2H_2O_{(l)}$
Given:
$1) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \rightarrow H_2O_{(l)} ; \Delta H^{\ominus} = -286 \ kJ$
$2) \ C_{(s)} + O_{2(g)} \rightarrow CO_{2(g)} ; \Delta H^{\ominus} = -394 \ kJ$
$3) \ CH_{4(g)} + 2O_{2(g)} \rightarrow CO_{2(g)} + 2H_2O_{(l)} ; \Delta H^{\ominus} = -890 \ kJ$

What is the enthalpy change for $2H_2O_{2(l)} \to 2H_2O_{(l)} + O_{2(g)}$ if the heats of formation of $H_2O_{2(l)}$ and $H_2O_{(l)}$ are $-188 \ kJ/mol$ and $-286 \ kJ/mol$ respectively?

Which of the following equations correctly represents the standard heat of formation $(\Delta H_f^o)$ of methane?

Molar enthalpy of combustion of $C_2H_{2(g)}$,$C_{(s)}$,and $H_{2(g)}$ are $-1300$,$-394$,and $-286 \ kJ/mol$ respectively. The standard enthalpy of formation of $C_2H_{2(g)}$ is $:$