C. Use the equation C(s) + 2H2(g) CH4(g), ΔH = –74.85, for the following questions. (5 points)
i. Is the formation of methane (CH4) an exothermic or endothermic reaction? (1 point)

ii. Draw a potential energy diagram for the reaction. (2 points)

iii. Label the graph with the following: "Reactants," "Products," "ΔHreaction," and "Ea." (2 points)

law of conservation of matter

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.