Use the formation reactions below such that when added together, they match the balanced equation for the combustion of methane. Cgraphite(s)+ 2H2(g) → CH4(g) ΔH 1=−74.80kJ
Cgraphite(s)+ O2(g) → CO2(g) ΔH2=−393.5k
H2(g)+ 1/2O2(g) → H2O(g) ΔH3=−241.80kJ
Calculate ΔHrxn for the combustion of methane, CH4(g).
CH4(g)+ 2O2(g) → CO2(g)+ 2H2O(g) ΔHrxn =kJ

ΔH of the reaction is -802.3kJ.

Explanation:

Using Hess's law, you can know ΔH of reaction by the sum of ΔH's of half-reactions.

Using the reactions:

(1) Cgraphite(s)+ 2H₂(g) → CH₄(g) ΔH₁ = −74.80kJ

(2) Cgraphite(s)+ O₂(g) → CO₂(g) ΔH₂ = −393.5k J

(3) H₂(g) + 1/2 O₂(g) → H₂O(g) ΔH₃ = −241.80kJ

The sum of (2) - (1) produce:

CH₄(g) + O₂(g) → CO₂(g) + 2H₂(g) ΔH' = -393.5kJ - (-74.80kJ) = -318.7kJ

And the sum of this reaction with 2×(3) produce:

CH₄(g) + 2 O₂(g) → CO₂(g) + 2H₂O(g) And ΔH = -318.7kJ + 2×(-241.80kJ) =

-802.3kJ

3 1/4 %

explanation:

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .