Basic concept in chemistry

1. 1
Seminar chemistry form 5 ( Revision for selaras 2)
Date : 5 th April 2011 ( Tuesday) Time: 3.15 pm
Name………………………………………………class……………………….teacher………….
1)
Refer to the diagram above:
Cell P Cell Q
Electrode M Electrode N Electrode R Electrode S
Name of cell
Label anode and
cathode
State products
State
observations
Write ionic
equations
State change of
energy

2. 2
2)
Answer the following questions
Electrode P Electrode Q
a) State all ions present
b) Label anode and
cathode
c) State ions attracted to
d) State ions discharged
e) State products and
what is the factor
involved?
f) Give a reason why you
have the product as
mentioned above?
g) Write ionic equations
h) State observations
and how do you test
the products?
i) If the experiment is
repeated with
concentration of
solution 0.001 mol
dm-3. State the
products . And what is
the factor involved?

3. 3
3) Organic reaction
CO2 + H2O
Reaction 1 Ethyl ethanoate
Ethene Reaction 2
Reaction 4
ethanol
Reaction 3
Reaction 5
Reaction 6
Ethanoic acid
A) Refer to the above reaction:
Reactions 1 2 3
a) Name of
reactions
b) Reagents used
c) Conditions
(if any)
d) Equations
Reactions 4 5 6
a) Name of
reactions
b) Reagents used
c) Conditions

4. 4
(if any)
d) Equations
B) Draw diagram for experiment to carry out for reaction 2
………………………………………………………………………………………………………………………………
4) DESCRIBE THE COAGULATION OF LATEX when exposed to air

5. 5
5) A student obtained the following data to determine heat of precipitation of lead(II) sulphate
(VI), PbSO4
Solution Volume (cm3) Concentration Initial temperature
(moldm-3) (oC)
Lead(II) nitrate 50 0.5 27.4
Sodium sulphate 50 0.5 27.6
Highest temperature = 30.5 oC
a) What is meant by heat of precipitation? …………………………………………………………………………………..
………………………………………..
…………………………………………………………………………………………………………………………………..
b) Using data above, calculate heat of precipitation of lead (II) sulphate
[Specific heat capacity 4.2 J g-1 o C-1 , density of solution , 1g cm-3 ]

6. 6
c) Write thermo chemical equation ……………………………………………………………………………
d) Write the ionic equation …………………………………………………………………………………………
e) Construct energy level diagram
…………………………………………………………………………………………….
f) The experiment is repeated, using potassium sulphate to replace sodium sulphate, with other
conditions remain constant, and it was found that heat of precipitation of lead(II) sulphate is the
same. Explain
…………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
6) A student carried out an experiment to determine heat of displacement of copper from copper
(II) sulphate solution . He added excess zinc powder to 50 cm3 of 0.20 mol dm-3 of copper(II)
sulphate solution. The thermo chemical equation is shown below
Zn + Cu 2+  Cu + Zn 2+ ∆H = -80.64kJ mol-1

7. 7
a) Using data above, calculate the change in temperature occur during the experiment
[Specific heat capacity 4.2 J g-1 o C-1 , density of solution , 1g cm-3 ]
……………………………………………………………………………………..
b) Write ionic equation …………………………………………………………………………………..
c) Experiments are repeated with the following changes. What is the effect on change in
temperature? Explain your answer
• concentration of copper(II) sulphate solution is doubled, without changing the
volume
…………………………………………………………………………………………………………………………
• The volume of copper(II) sulphate solution is halved without changing the
concentration
……………………………………………………………………………………………………….
7) State differences between heat change and heat of reaction
Heat change Heat of reaction
a) Other names Depends on name of reactions
1)
2)

8. 8
3)
4)
b) What formula to use ?
c) Unit?
d) Symbol?
END…..