Answer:
Explanation:
A <em>combustion reaction</em> is the reaction with oxygen along with the release of energy in form of heat or light.
Organic compounds (like CH₄) undergo combustion forming water and CO₂.
The combustion reaction of CH₄ is:
Hence, the first equation from the choices is not showing the combustion reaction of CH₄.
Not only organic compounds can undergo combustion. Metals and no metals can undergo combustion, i.e. metals and no metals can react with oxygen releasing light or heat.
The reaction of copper and oxygen (second choice) is a combustion reaction:
The formation of water (2H₂ + O₂ → 2H₂O) is other example of a combustion reaction where no organic compounds are involved.
On the other hand, the other two equations from the choice list are not reactions with oxygen, so they do not show combustion reactions.
Answer: 350 kj/mol
Explanation:
As shown below this expression gives the activation energy of the reverse reaction:
EA reverse reaction = EA forward reaction + | enthalpy change |
1) The activation energy, EA is the difference between the potential energies of the reactants and the transition state:
EA = energy of the transition state - energy of the reactants.
2) The activation energy of the forward reaction given is:
EA = energy of the transition state - energy of [ NO2(g) + CO(g) ] = 75 kj/mol
3) The negative enthalpy change - 275 kj / mol for the forward reaction means that the products are below in the potential energy diagram, and that the potential energy of the products, [NO(g) + CO2(g) ] is equal to 75 kj / mol - 275 kj / mol = - 200 kj/mol
4) For the reverse reaction the reactants are [NO(g) + CO2(g)], and the transition state is the same than that for the forward reaction.
5) The difference of energy between the transition state and the potential energy of [NO(g) + CO2(g) ] will be the absolute value of the change of enthalpy plus the activation energy for the forward reaction:
EA reverse reaction = EA forward reaction + | enthalpy change |
EA reverse reaction = 75 kj / mol + |-275 kj/mol | = 75 kj/mol + 275 kj/mol = 350 kj/mol.
And that is the answer, 350 kj/mol
Answer:
Explanation:
The relation between new scale and absolute temperature scale is given as follows
Aw = 2 K
for K = 273.15 ( freezing point of water at absolute scale )
Aw = 2 x 273.15 = 546.3 K
So each division of new scale is half the each division of absolute scale
each division of new scale is small .
The value of R = 8.314 J per mole per K
Here per K is equivalent to 2Aw
So the vale of R in new scale = 8.314/2 J per mole per Aw
= 4.157 J per mole per Aw
k = R / N
= 4.157 / 6.02 x 10²³
= .69 x 10⁻²³
= 6.9 x 10⁻²⁴ J per molecule per Aw .
