During a combustion reaction, carbon dioxide and water are produced from an hydrocarbon and oxygen.
In this case the hydrocarbon is methane.
The combustion of methane is given by the following chemical equation:
-130KJ is the standard heat of formation of CuO.
Explanation:
The standard heat of formation or enthalpy change can be calculated by using the formula:
standard heat of formation of reaction = standard enthalpy of formation of product - sum of enthalpy of product formation
Data given:
Cu2O(s) ---> CuO(s) + Cu(s) ∆H° = 11.3 kJ
2 Cu2O(s) + O2(g) ---> 4 CuO(s) ∆H° = -287.9 kJ
CuO + Cu ⇒ Cu2O (-11.3 KJ) ( Formation of Cu2O)
When 1 mole Cu20 undergoes combustion 1/2 moles of oxygen is consumed.
Cu20 + 1/2 02 ⇒ 2CuO (I/2 of 238.7 KJ) or 119.35 KJ
So standard heat of formation of formation of Cu0 as:
Cu + 1/2 02 ⇒ CuO
putting the values in the equation
ΔHf = ΔH1 + ΔH2 (ΔH1 + ΔH2 enthalapy of reactants)
heat of formation = -11.3 + (-119.35)
= - 130.65kJ
-130.65 KJ is the heat of formation of CuO in the given reaction.
Answer:
Equal
Explanation:
Energy is always conserved in the nature and it is an universal law. According to the law conservation of energy, it is said that energy can never be created out of something and we can never destroy and vanish any energy in any form. Energy in any form can only be transformed to some other forms of energy. This is known as conversion of energy.
In the context, the chemical energy that is produced by the battery and the electrical energy produced should be equal.
A
Explanation:
The coiling up of DNA with the help of histone proteins - to what is called heterochromatic regions- is part of gene regulation. This makes genes inaccessible to RNA polymerase that makes mRNA from the genes. When the genes are exposed by DNA unwinding, these genes are transcribed and the resulting mRNAs are translated by ribosomes into proteins.
The DNA never unwinds completely, but rather does so region by region, because if it does so it would become so long that it wouldn't fit in the nucleus or cell.
