Question

CH4 (g) yields C(g) + 4H (g) (reaction for expansion)

Answer 1

Answer:

Here's what I find.

Explanation:

$\rm CH _{4} (g) \, \rightleftharpoons \, C(g) + 4H(g)$

$\text{Same} =\begin{cases}1. & \text{The number of atoms of each element}\\2. & \text{The state of the methane molecules}\\4. &\text{The state of the carbon atoms}\\\end{cases}$

$\text{Different} =\begin{cases}3. & \text{The enthalpy change of the reaction}\\\end{cases}$

The sign of ΔH changes when you reverse the reaction.  

Answer 2

Answer:

Same:

-the number of atoms

of each element

-the state of the

methane molecules

Different:

-the state of the

carbon atoms

-the enthalpy change

of the reaction

Explanation:

The enthalpy changes are different for the two reactions even though all the same elements are involved in equal numbers. This illustrates that the enthalpy change of a reaction is dependent on the states of the reactants and products, as well as how the atoms are bonded.