multiple choice question\nhow would you determine the heat released when 28.3 g of methane burns, given the…

multiple choice question\nhow would you determine the heat released when 28.3 g of methane burns, given the following thermochemical equation?\nch₄(g) + 2o₂(g) → co₂(g) + 2h₂o(g) δh = -891 kj\n\ndivide δh by the amount of methane in moles.\nthe answer is equal to δh regardless of the quantity of reactant.\nconvert the mass of methane to moles, then multiply by δh.\nmultiply the mass of methane by δh.

multiple choice question\nhow would you determine the heat released when 28.3 g of methane burns, given the following thermochemical equation?\nch₄(g) + 2o₂(g) → co₂(g) + 2h₂o(g) δh = -891 kj\n\ndivide δh by the amount of methane in moles.\nthe answer is equal to δh regardless of the quantity of reactant.\nconvert the mass of methane to moles, then multiply by δh.\nmultiply the mass of methane by δh.

Answer

Explanation:

Step1: Recall molar - heat relationship

The $\Delta H$ given in the thermochemical equation is for the reaction as written in moles. First, we need to convert the mass of methane to moles. The molar mass of $CH_4$ is $M=(12 + 4\times1)\text{ g/mol}=16\text{ g/mol}$. The number of moles of $CH_4$, $n=\frac{m}{M}$, where $m = 28.3\text{ g}$.

Step2: Determine heat released

The heat released $q$ is related to the number of moles of the reactant and the $\Delta H$ of the reaction. The heat released for a given amount of reactant is $q=n\times\Delta H$, where $n$ is the number of moles of the reactant and $\Delta H$ is the enthalpy change of the reaction per mole of the reaction as written. So we convert the mass of methane to moles and then multiply by $\Delta H$.

Answer:

C. Convert the mass of methane to moles, then multiply by $\Delta H$