Form 4 Chemistry national exam 2024/2025 with answers
The 2024/2025 Form 4 national exam paper for Form 4 Chemistry, question by question. Take it timed like the real exam, then see the answer and explanation to every question.
- 69 questions, 100 marks
- 120 minutes
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120 minutes, 100 marks. Multiple choice is marked for you; you mark your written answers against the marking points.
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Instructions to candidates
Answer all questions. Read each question carefully before answering. Write your answers on the exam paper. Time: 2 hours.
SECTION A: Circle the Correct Answer (40 Marks)
- 11 mark
Which branch of science relates to all branches of science?
- A.Physics
- B.Geography
- C.Biology
- D.Chemistry
- 21 mark
Which one of the following compounds has the maximum number of hydrogen atom
- A.Butene
- B.Butyl
- C.Butane
- D.Buytne
- 31 mark
Which part of the atmosphere contains the ozone (O3) layer?
- A.Troposphere
- B.Stratosphere
- C.Thermosphere
- D.Mesosphere
- 41 mark
The molar mass of CaCO3 given atomic mass of (Ca = 40 C = 12 O = 16)
- A.98 g/mole
- B.89 g/mole
- C.101 g/mole
- D.100 g/mole
- 51 mark
The figure below states a change of state of matter. What process occurs the part labeled at X
- A.Condensation
- B.Melting
- C.Evaporation
- D.Freezing
- 61 mark
Which of the following does NOT belong to conditions for a reaction to occur?
- A.Collision
- B.Power
- C.Energy
- D.Orientation
- 71 mark
The IUPAC name for product formed when CH3-CH2-CH2-O-K + CH3-CH2-Br is
- A.Ethoxy ethane
- B.Methoxy ethane
- C.Ethoxy propane
- D.Methoxy propane
- 81 mark
The PH of a solution was determined to be 3.5, The [H3O+] ion of that solution is:
- A.1.5 × 10^-4 M
- B.3.2 × 10^-4 M
- C.5.1 × 10^-4 M
- D.2.3 × 10^-4 M
- 91 mark
The horizontal rows of the periodic table
- A.Triad
- B.Group
- C.Trends
- D.period
- 101 mark
The figure below represent the structural formula of glucose, it has molecular formula C6H12O6, what will be its configuration
- A.α -sugar
- B.D- sugar
- C.β -sugar
- D.L-sugar
- 111 mark
The figure below show that the penetrating ability of radioactive emissions by using the detector labeled part at Z is
- A.Alpha
- B.Beta
- C.Gamma
- D.Neutron
- 121 mark
The chemical formula of aluminum sulphate is
- A.Al2 SO4
- B.Al3 SO4
- C.Al2(SO4)3
- D.Al SO4
- 131 mark
If a nucleotide was obtained to have 30% of adenine nucleotides, how many guanine will have
- A.40%
- B.10%
- C.30%
- D.20%
- 141 mark
The quantity of electricity requires to deposit one mole of Magnesium ion
- A.1 F
- B.2F
- C.3F
- D.4F
- 151 mark
Which one of the following changes will increase the rate of chemical reaction
- A.Decrease temperature
- B.Removing of catalyst
- C.Increase temperature
- D.Decreasing amount of reactant
- 161 mark
A Student has balloons filled with three different gases. The symbols for the gas inside are written on each balloon. To which group of the periodic table do the gases belong? (The balloons show He, Ar and Ne.)
- A.Group 5
- B.Group 6
- C.Group 7
- D.Group 8
- 171 mark
By the evaluating the molecular weight of the below alcohols, which alcohol has the highest boiling point
- A.Pentanol
- B.butanol
- C.propanol
- D.methanol
- 181 mark
Which carbon allotrope represent by the picture below
- A.Diamond
- B.Bucky ball
- C.Graphite
- D.Giant
- 191 mark
The chemical symbol of Tungsten is
- A.Tg
- B.Tn
- C.W
- D.M
- 201 mark
The reaction below shows a reaction at equilibrium. HCl(g) + NaOH(aq) ⇌ NaCl(aq) + H2O(l). Find the equilibrium constant Kc and then analyze the direction which shift the reaction if their concentrations are [HCl] = 3.2M [NaOH] = 4.3m [NaCl] = 6M and [H2O] = 2M
- A.0.22 left
- B.0.44 right
- C.0.22right
- D.0.44 left
- 211 mark
The structures below states that some organic compounds, which structure illustrates carboxylic acid
- A.Structure A
- B.Structure B
- C.Structure C
- D.Structure D
- 221 mark
How many electrons are shared to form a double bond?
- A.8
- B.8
- C.4
- D.2
- 231 mark
Calculate the oxidation number of Sulfur in H2SO4
- A.+6
- B.+8
- C.-8
- D.-6
- 241 mark
The reaction between carboxylic acid and alcohol is called _____
- A.Neutralization
- B.Radiation
- C.Esterification
- D.Precipitation
- 251 mark
If C2H4 reacts with HBr. What is the molecular formula of the product?
- A.C2H3Br
- B.C2H2Br
- C.C2H4Br
- D.C2H5Br
- 261 mark
When salt is added to water, a solution is formed as shown in the diagram below. What term is used to describe the water
- A.Solute
- B.Solvent
- C.Salination
- D.Saponificatin
- 271 mark
All are conditions required the chemical reaction to reach the equilibrium state EXCEPT
- A.Open system
- B.Closed system
- C.Constant Temperature
- D.Equal rates both directions
- 281 mark
The structure of a common household substance is given below:
- A.C6H7Cl
- B.C8H8Cl
- C.C8H9Cl
- D.C7H8Cl
- 291 mark
What is the valence electron configuration of group 15?
- A.ns^2np^2
- B.ns^2np^1
- C.ns^2np^4
- D.ns^2np^3
- 301 mark
The expression of equilibrium concentrations for a reaction below is: 2SO2(g) + 3O2(g) ⇌ 2SO3(g)
- 311 mark
The table below shows compounds A to E, where R represents a CH3 group and R' represents a C2H5 group. Which structures are alcohols
- A.Structure B and C
- B.Structure D and E
- C.Structure A and C
- D.Structure C and E
- 321 mark
Organic compounds which contain oxy (- O -) as a functional group.
- A.Alcohol
- B.Phenol
- C.Ether
- D.ester
- 331 mark
The splitting of the nucleus of an atom into lighter nucleus
- A.Nuclear fusion
- B.Nuclear fission
- C.Decay
- D.Half life
- 341 mark
The number of possible isomers for octane with molecular formula of (C8H18)
- A.5
- B.9
- C.18
- D.35
- 351 mark
235/92 U + 1/0 n → x/30 Z + 160/y Sn + 4(1/0 n). The value of X in the nuclear equation above is
- A.72
- B.27
- C.173
- D.137
- 361 mark
Which of the following elements belong to Alkali metal elements
- A.Barium
- B.Cesium
- C.Calcium
- D.Radium
- 371 mark
The mechanism of this reaction consists two elementary steps: step 1: 2NO(g) + O2(g) → N2O2(g); step 2: N2O2(g) + O2(g) → 2NO2(g). The intermediate species that appears in the mechanism of reaction is
- A.NO2
- B.N2O
- C.NO
- D.N2O2
- 381 mark
Which of the following is an example of exothermic reactions?
- A.Decomposing of stone
- B.Heating of butter
- C.Explosion
- D.Evaporation
- 391 mark
The isotope shown 218/84 Po determine its number of neutrons
- A.134
- B.84
- C.218
- D.136
- 401 mark
The diagram below shows a section of periodic table and symbols of first 20 elements. Which two elements belongs to group 13 elements
- A.Li and Be
- B.B and Al
- C.O and S
- D.K and C
SECTION B: Structured Questions (60 Marks)
- 41a3 marks
The diagram shows a reaction sequence: butane → (X) → ethene → (Y) → ethanol → (Z) → carbon dioxide and water. Name the processes labeled at: a) Y
- 41b3 marks
The diagram shows a reaction sequence: butane → (X) → ethene → (Y) → ethanol → (Z) → carbon dioxide and water. Name the processes labeled at: b) Z
- 42a1 mark
Describe the general formula of a) Alkane
- 42b1 mark
Describe the general formula of b) Benzene
- 434 marks
A sample gas occupies a volume of 1 liter at a pressure of 1 atm, At what pressure will its volume be 0.5 liter? (assuming temperature is constant)
- 44a3 marks
The table below which is collected at a set of temperature: Experiment 1: [A] = 0.20M, [B] = 0.20M, Rate = 0.4 M/s; Experiment 2: [A] = 0.20 M, [B] = 0.040M, Rate = 0.8 M/s; Experiment 3: [A] = 0.40 M, [B] = 0.20M, Rate = 1.6 M/s. a) Determine the rate law?
- 44b3 marks
The table below which is collected at a set of temperature: Experiment 1: [A] = 0.20M, [B] = 0.20M, Rate = 0.4 M/s; Experiment 2: [A] = 0.20 M, [B] = 0.040M, Rate = 0.8 M/s; Experiment 3: [A] = 0.40 M, [B] = 0.20M, Rate = 1.6 M/s. b) Calculate the value of rate constant?
- 45a1 mark
Identify the following elements as metals, non-metals and metalloids. a. Silicon
- 45b1 mark
Identify the following elements as metals, non-metals and metalloids. b. Mercury
- 45c1 mark
Identify the following elements as metals, non-metals and metalloids. c. Carbon
- 45d1 mark
Identify the following elements as metals, non-metals and metalloids. d. Gold
- 462 marks
What are types of physical forms of radiation?
- 47a2 marks
Reactions can be classified into exothermic and endothermic reaction. In the figure below is reaction profile (the products are at a higher energy than the reactants). a) What is type of reaction indicate above reaction profile
- 47b1 mark
Reactions can be classified into exothermic and endothermic reaction. In the figure below is reaction profile (the products are at a higher energy than the reactants). b) Describe the sign of ΔH the reaction you mentioned in "a"
- 484 marks
Sodium atom reacts with chlorine molecule gas to forma sodium chloride. Write balanced chemical equation of above reaction
- 49a2 marks
Amino acids combine to form proteins, when four amino acids are linked they form tetra peptides. The figure shows the tetrapeptide H2N-Cys-His-Glu-Met-COOH with the amino acids labelled Cytosine (C), Histidine (H), Glutaric acid (E) and Methionine (M) from left to right. a) By using the above figure which amino acid is N-terminal
- 49b2 marks
Amino acids combine to form proteins, when four amino acids are linked they form tetra peptides. The figure shows the tetrapeptide H2N-Cys-His-Glu-Met-COOH with the amino acids labelled Cytosine (C), Histidine (H), Glutaric acid (E) and Methionine (M) from left to right. b) By using the above figure which is C-terminal
- 50a3 marks
Calculate the pH of each of the following a. [OH-] = 1.5 × 10^-5
- 50b3 marks
Calculate the pH of each of the following b. [H3O+] = 2.3 × 10^-2
- 514 marks
What is the equilibrium constant, Kc, if the equilibrium concentrations are as follows: PCl5 is 0.096 M, PCl3 is 0.024 M and Cl2 is 0.024 M. PCl5(g) ⇌ PCl3(g) + Cl2(g)
- 52i1 mark
Salt bridge is U shaped tube filled with a mixture of agar-agar which plays an important roles in Galvanic cell. Name the labeled parts (i) Q and S (ii) by using the figure below. i. Q
- 52ii1 mark
Salt bridge is U shaped tube filled with a mixture of agar-agar which plays an important roles in Galvanic cell. Name the labeled parts (i) Q and S (ii) by using the figure below. ii. S
- 53a2 marks
The following table shows the boiling points of alkanes, aldehydes, ketones and alcohols: Pentane CH3CH2CH2CH2CH3 36 °C; Butanal CH3CH2CH2CHO 76 °C; 2-butane CH3CH2COCH3 80 °C; 1-butanol CH3CH2CH2CHOH 118 °C. Use the table to answer these questions: a. Explain why aldehydes and ketones have lower boiling points than alcohols?
- 53b2 marks
The following table shows the boiling points of alkanes, aldehydes, ketones and alcohols: Pentane CH3CH2CH2CH2CH3 36 °C; Butanal CH3CH2CH2CHO 76 °C; 2-butane CH3CH2COCH3 80 °C; 1-butanol CH3CH2CH2CHOH 118 °C. Use the table to answer these questions: b. Predict which one has a higher boiling point pentane or butanal? Justify your answer.
- 54a1 mark
Indicate whether the reaction rate increase or decrease: a. Adding of catalyst in reaction
- 54b1 mark
Indicate whether the reaction rate increase or decrease: b. Decreasing temperature
- 54c1 mark
Indicate whether the reaction rate increase or decrease: c. Decreasing the concentration of reactant
- 54d1 mark
Indicate whether the reaction rate increase or decrease: d. Reducing size of solid reactant
- 555 marks
The half life of the polonium-210 is 138.4 days. How many milligrams of polonium-210 remains after 692 days if the starting with 8mg of isotope?
Paper set by the Federal Ministry of Education, Culture and Higher Education (MoECHE), Somalia. Shared free of charge to help students prepare. The answers and explanations are written by Sheerxirfad teachers.
