Page 94 - Chemistry

b) Iodine can react with chlorine as shown below:-
I 2(g) + Cl (g) 2lcl (s) DH= -68kJ
Determine the molar enthalpy change for this reaction
c) Draw an energy level diagram for the reaction in (b) above
27. Study the diagram below and answer the questions that follow:

+ -
NH 4 (g) + Cl (g)

∆H 2

∆H 1 NH 4 ( aq) + Cl ( aq)
+
-

Energy
∆H 3
NH 4Cl( s)

Reaction Co-ordinate
Reaction Co-ordinate

a) What do ∆H 1 and ∆H 2 represent?
∆H 1 …………………………………………………………………….
∆H 2 ……………………………………………………………………..
b) Write an expression to show the relationship between ∆H 1, ∆H 2 and ∆H 3.

Reaction rates and reversible reactions
1. Study the following equilibrium reaction and answer the questions that follow:-
+
-
HL (aq) + H 2O( l) H 3O (aq) L (aq)
Red Blue
+
+
Given that in an acid solution, H 3O (aq) act in place of hydrogen ions, H , according to the
equation.
-
H 3O (aq) + OH (aq) 2H 2O (l)
Explain what would be observed when potassium hydroxide solution is added to the above
equilibrium mixture

2. The scheme below shows the energy changes that take place between ice, water and steam.
Study it and answer the questions that follow:-
H 1 H 2
H 2O (s) H 2O (l) H 2O (g)
H 4 H 3
(a) What name is given to the energy change H 4?
(b) What is the sign H 3, give a reason

3. The table below gives bond energies for three covalent bonds

Bond Bond energy (KJmol-1)
H –H 435
Cl – Cl 240

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