Answer:
C(graphite) → C(diamond), ΔH = - 0.45 kcal
CH4 + 2O2 → CO2 + 2H2O + 212,800 cal
Explanation:
C(graphite) → C(diamond), ΔH = - 0.45 kcal
CH4 + 2O2 → CO2 + 2H2O + 212,800 cal
These reactions are exothermic reaction because heat is evolved.
The energy changes occur during the bonds formation and bonds breaking.
There are two types of reaction endothermic and exothermic reaction.
Endothermic reactions:
The type of reactions in which energy is absorbed are called endothermic reactions.
In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.
For example:
C + H₂O → CO + H₂
ΔH = +131 kj/mol
it can be written as,
C + H₂O + 131 kj/mol → CO + H₂
Exothermic reaction:
The type of reactions in which energy is released are called exothermic reactions.
In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.
For example:
Chemical equation:
C + O₂ → CO₂
ΔH = -393 Kj/mol
it can be written as,
C + O₂ → CO₂ + 393 Kj/mol
Answer:
Explanation:
Electron affinity is the energy released in adding an electron to a neutral atom in the gas phase.
It is a measure of the readiness of an atom to gain an electron. This property is very peculiar to non-metals. The higher the value, the greater the tendency to accept electrons.
Across a period electron affinity increases due to the increasing nuclear charge not being compensated for.
Down a group, electron affinity decreases due to the low nuclear charge and the large atomic radii.
The exception to this rule is the stability of half-filled sublevels. For example, nitrogen has a configuration of 2,5 with sublevel notation of 1s²2s²2p³.
The p-sublevel has a degeneracy of three and the three electrons goes in singly. This makes the configuration stable.
We expect such an atom to have a higher electron affinity but its configuration is stable and carbon would have a higher affinity than it across the same period.
Half filled sublevels are exception to the trend of electron affinity.
Mass:20g
Mole=20/[2(23)+16]
=0.32 mil
The correct answer is carbon.
The element carbon is found in all the organic constituents in the body of a human that comprises carbohydrates, fats, proteins, and nucleic acids. It is the second most abundant element found in the body of a human being. In supplementation to being a basic building block of the majority of the cellular compositions of the body, carbon is found in the blood as carbonic acid and bicarbonates.
The chemical equation for this reaction is this:
CO2 + 4H2 = CH4 + 2H2O
from the equation, the mole ration of CO2 to CH4 is ratio 1:1
and CH4 = 25.1
The mole ratio of H2 to H2O is 4:2
therefore, mole of H2 = 19.1* 4/2 = 38.2
The moles of methane produced is 38.2 moles
