Concept explainers
For the reactions of molecular hydrogen with fluorine and with chlorine:
- (a) Calculate the enthalpy change for breaking all the bonds in the reactants.
- (b) Calculate the enthalpy change for forming all the bonds in the products.
- (c) From the results in parts (a) and (b), calculate the enthalpy change for the reaction.
- (d) Which reaction is most exothermic?
(a)
Interpretation:
The enthalpy change for breaking of all bonds present in all reactants of given reaction has to be calculated.
Answer to Problem 61QRT
The enthalpy change value for breaking of bonds for fluorine reaction is
Explanation of Solution
The reaction of molecular hydrogen with fluorine and chlorine is as follows,
Above both reactions, involves breaking of1
(b)
Interpretation:
The enthalpy change for forming of all bonds present in all products of given reaction has to be calculated.
Answer to Problem 61QRT
The enthalpy change value for forming of bonds in fluorine reaction is
Explanation of Solution
The reaction of molecular hydrogen with fluorine and chlorine is as follows,
Above both reactions involve formation of 2 hydrogen-halogen bonds. The
(c)
Interpretation:
The enthalpy change given reaction has to be calculated.
Concept Introduction:
The enthalpy change in a system
Where,
Answer to Problem 61QRT
The enthalpy change value for fluorine reaction is
Explanation of Solution
The reaction of molecular hydrogen with fluorine and chlorine is as follows,
The enthalpy change value for each reaction is determined by considering the formula,
(d)
Interpretation:
From the two given reactions, the exothermic reaction has to be identified.
Concept Introduction:
Enthalpy is the amount energy absorbed or released in a process. Under constant pressure conditions the enthalpy change will be equal to molar q.
Exothermic reaction: Exothermic reactions are those in which evolution of heat takes place during any chemical reaction. They release heat because the reactant molecules require less heat for breakage of bonds than the product molecules.
Endothermic reaction: Endothermic reactions are those in which heat is absorbed during any chemical reaction. In such type of reactions, external energy is needed.
Answer to Problem 61QRT
The reaction between molecular hydrogen and fluorine is more exothermic than the other one.
Explanation of Solution
The reaction of molecular hydrogen with fluorine is more exothermic since
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Chapter 4 Solutions
CHEMISTRY:MOLECULAR SCI.-STUD.SOLN.MAN.
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