Determine the overall energy change for the reaction between hydrogen and oxygen shown in Question 13. Use Figure 2.

–500KJ

Explanation:

Data obtained from the question include the following:

Heat of reactant (Hr) = 800KJ

Heat of product (Hp) = 300KJ

Enthalphy change (ΔH) =..?

The enthalphy change is simply defined as the difference between the heat of product and the heat of reactant i.e

Enthalphy change = Heat of product – Heat of reactant

ΔH = Hp – Hr

With the above formula, we can easily calculate the enthalphy change as follow

ΔH = Hp – Hr

ΔH = 300 – 800

ΔH = –500KJ.

Therefore, the overall energy change for the reaction between hydrogen and oxygen shown in the diagram above is –500KJ

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.