Answer for P1:
1 B 26 B
2 B 27 C
3 D 28 A
4 A 29 A
5 D 30 C
6 C 31 C
7 B 32 C
8 A 33 B
9 D 34 C
10 A 35 D
11 C 36 B
12 C 37 C
13 D 38 D
14 A 39 C
15 D 40 B
16 D 41 C
17 D 42 B
18 C 43 C
19 B 44 D
20 B 45 C
21 A 46 D
22 B 47 C
23 B 48 C
24 A 49 D
25 A 50 B
Tuesday, November 29, 2011
Thursday, October 27, 2011
Thursday, August 25, 2011
Tuesday, August 23, 2011
Tuesday, August 16, 2011
Form 4 Revision
Chapter 2 Structure of Atom
1 Table 1 shows the incomplete information about 3 atoms; X, Y and Z.
Atom | Proton number | Number of neutron | Number of electron |
X | 8 | 6 | |
Y | 6 | 6 | |
Z | 17 | 17 |
Table 1
(a) State the name of subatomic particles that are found in nucleus of an atom.
…………………………………………………………………………………………… [1 mark]
(b) (i) What is the term of the total number of protons and neutrons in an atom?
…………………………………………………………………………………… [1 mark]
(ii) The total number of protons and neutrons for atom Z is 35.
What is the number of neutron in atom Z?
…………………………………………………………………………………… [1 mark]
(iii) Write the symbol for atom Z in the form of A X.
Z
…………………………………………………………………………………… [1 mark]
(iv) Draw the atomic structure of atom Z.
[1 mark]
(c) Atom X and atom Y are isotopes of an element.
(i) What is the proton number of atom X?
…………………………………………………………………………………… [1 mark]
(ii) Write the electron arrangement of atom Y.
…………………………………………………………………………………… [1 mark]
(iii) What is valence electron of atom X?
…………………………………………………………………………………… [1 mark]
(iv) Why atom X and atom Y has same chemical properties?
…………………………………………………………………………………… [1 mark]
(v) State one use of the isotope X in archaeology field.
…………………………………………………………………………………… [1 mark]
2 Diagram 2 shows the chemical symbols which represent three elements X, Y and Z
The letters used are not the actual symbols of the elements.
9 X 4 | 32 Y 15 | 31 Z 15 |
Diagram 2
(a) (i) What is meant by proton number?
…………………………………………………………………………………… [1 mark]
(ii) State the proton number for atom X
……………………………………………………………………………………… [1 mark]
(b) What is represented by the number 32 for the element Y?
……….…………………………………………………………………………………… [1 mark]
(c) (i) Atom Y and Z are isotopes. State the difference between the two atoms.
..……………………………………………………………………………………… [1 mark]
(ii) State one use of isotopes in daily life.
……………….……………………………………………………………………… [1 mark]
(d) (i) Write the electron arrangement of atom Y.
……………………………………………………………………………………… [1 mark]
(ii) Determine the number of valence electron for atom Y.
……………………………………………………………………………………… [1 mark]
(ii) Draw the electron arrangement for atom Z.
[2 marks]
3 Diagram 3.1 shows the arrangement of particles of substance X at different temperatures.
 |
(a) What is the physical state of substance X at
(i) 60 oC : .........................................................................
(ii) 90 oC : ......................................................................... [2 marks]
(b) State the movement of particles of substance X at 60 oC.
....……………………………………………………………………………………… [1 mark]
(c) Graph 3.2 shows the graph of temperature against time when substance X is heated from 60 oC to 90 oC. (i) What is meant by melting point?
……………………………………………………………………………………………..
……………………………………………………………………………………[1 mark]
(ii) Based on Graph 3.2, state the melting point of substance X.
…………………………………………………………………………………… [1 mark]
(iii) Explain why the temperature remains constant from t1 to t2.
...................................................................................................................................
................................................................................................................................[2 marks]
(d) (i) Substance X cannot conduct electricity in any state.
State the type of particles of substance X.
..................................................................................................................................[1 mark]
(ii) Table 3.3 shows two substances.
Magnesium oxide | |
Carbon dioxide |
|
Which substance has the same type of particles as substance X?
Tick (√ ) the correct answer.
[1 mark]
Tuesday, June 21, 2011
Monday, June 13, 2011
Monday, May 23, 2011
Wednesday, May 18, 2011
Form 5 Chapter 4 Thermochemistry
Describe an experiment to determine the heat of precipitation of silver chloride
Diagram:
Apparatus:
Measuring cylinders, thermometer and plastic cup
Materials:
0.5 mol dm-3 silver nitrate solution, 0.5 mol dm-3 sodium chloride solution
Procedure: | ||
1. 25cm3 of 0.5 mol dm-3 sodium chloride solution is measured and poured into a clean and dry plastic cup using a measuring cylinder. 2. The initial temperature of sodium chloride solution is measured and then recorded. 3. Using another measuring cylinder, 25 cm3 of 0.5 mol dm-3 silver nitrate solution is measured. The initial temperature of the silver nitrate solution is measured after 5 minutes and recorded. 4. The silver nitrate solution is poured quickly and carefully into the sodium chloride solution. 5. The mixture is stirred with a thermometer throughout the experiment and the highest temperature obtained is recorded. | ||
Result: | ||
Mass, m | c | q |
= (25 + 25) g = 50 g | 4.2 | Initial temperature of sodium chloride solution = T1oC Initial temperature of the silver nitrate = T2 oC Highest temperature reached = T4 oC => Average initial temperature = (T1+T2)/2 = T3 oC è Increase in temperature, q = (T4 - T3) oC |
Calculation: | ||
No of moles of sodium chloride used | No of moles of silver nitrate used | |
= MV/1000 = 0.0125 mole | = MV/1000= 0.0125 mole | |
Chemical equation: AgNO3 (aq) + NaCl (aq) Ã AgCl (s) + NaNO3 (aq) Ionic equation: Ag + (aq) + Cl- (aq) Ã AgCl (s) 1 mole 1 mole 1 mole Heat released = mcq = (25 + 25 ) x 4.2 x (T4 - T3) = x J 0.0125 mole of AgCl precipitated releases x J of heat energy. Therefore, 1 mole of AgCl precipitated will released Heat of precipitation, DH = x/0.0125 J = y J Thermochemical equation: AgNO3 (aq) + NaCl (aq) Ã AgCl (s) + NaNO3 (aq) DH = - y/1000 kJmol-1 | ||
Form 5 Chapter 4 Thermochemistry
Planning of experiment:
| 1 | | Different members of this homologous series have different heat of combustion. Table below shows the heat of combustion of some alcohols. | | |||||||||||||||||||||||||||||||||||||||
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| | | Plan a laboratory experiment to determine the heat of combustion of alcohols shown in the table. Your planning should include the following aspects: | ||||||||||||||||||||||||||||||||||||||||
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| | | (a) Statement of the problem Pernyataan masalah (b) All the variables Semua pembolehubah (c) Hypothesis Hipotesis (d) List of materials and apparatus Senarai bahan dan radas (e) Procedure Prosedur (f) Tabulation of data Penjadualan data [17 marks] [17 markah] Suggested Answer:
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