Chemistry Paper 1 Questions and Answers - Maranda High Pre Mock Exams 2023

Instructions to Candidates  

• Answer ALL the questions in the spaces provided below each question.
• Mathematical tables and silent electronic calculators may be used. 
• All working MUST be clearly shown where necessary. 

1. The set up below represents the apparatus that may be used to separate a mixture of two miscible  liquids C and D whose boiling points are 80⁰C and 110⁰C. 
   
   1. Name B ( 1 mark)
   2. What is the purpose of the thermometer (1mark)
   3. Which liquid was collected in the test tube? (1mark)
2. Substances can be classified as either a mixture, compound or pure elements.  Give two reasons why air is classified as a mixture. (2marks)
3. Describe how you can extract oil from ground nuts. (3marks)
4. Study the information in the table below and answer the questions that follow. The letters do not  represent the actual symbols of the elements. 
   

   Substance	Solubility in water	Electrical conductivity
   		Solid	Molten
   A	Insoluble	Good	Good
   B	Soluble	Poor	Good
   C	Insoluble	Poor	Poor

   1. Which of the substances is highly likely to be sodium chloride? Explain (1mark)
   2. What type of bond exists in substance A? (1mark)
   3. State a possible structure in substance C? (1mark)
5. The table below shows behaviour of metals R, X, Y and Z. Study it and answer the questions that  follow. 
   

   Metal	Appearance on  exposure to air	Reaction in water	Reaction with dilute  hydrochloric acid
   R	Slowly tarnishes	Slow	Vigorous
   X	Slowly turns white	Vigorous	Violent
   Y	No change	Does not react	Does not react
   Z	No change	No reaction	Reacts moderately

   1. Arrange the metals in the order of reactivity starting with the least reactive. (2 marks)
   2. Name a metal which is likely to be Y. (1 mark)
6. The table below gives information about ions of P and Y 
   

   Ion	P+	Y2-
   Electron arrangement	2.8	2.8.8
   Number of Neutrons	12	16

   1. Write the electron arrangement for the atom of Y (1mark)
   2. How many protons are there in the nucleus of (1mark) (i)
      1. P……………………………………………………………………………………... 
      2. Y……………………………………………………………………………………
   3. Write the formula of the compound formed when P and Y reacts (1mark)
7. Use the scheme below to answer the following questions. 
   
   1. Name the type of reaction which takes place between ethan-1,2-dioic acid and concentrated sulphuric (VI) acid (1mark)
   2. Why is the gaseous mixture passed through concentrated KOH? (1mark)
   3. Write a chemical equation that produces gas C and E (1mark)
8. The set up below can be used for the laboratory preparation of product W. 
   
   1. Write chemical equation for the reaction that takes place in the retort flask. (1 mark)
   2. Explain why product W appears yellow in colour. How is the colour removed? (2 marks) 
9. Starting with 100cm³of 2.0M sodium hydroxide solution, describe how to prepare pure sodium  sulphate crystals. (3marks)
10. Study the set up below used to investigate the properties of ammonia gas. 
    
    1. State two observations made in this experiment. (1mark)
    2. What is the purpose of using the hot wire in this experiment? (1mark)
    3. State the identity of the hot spiral of metal U. (1mark)
11. 3.1g of an organic compound containing carbon, hydrogen and oxygen only, produced 4.4g of  carbon (IV) oxide and 1.8g of water on complete combustion. Determine its molecular formula if  its formula mass is 60. (3marks)  
12. A student collected samples of water from two different sources. She measured equal volume of  water in two different test-tubes. She added soap solution from a burette until permanent lather was  formed. She then boiled another two samples of the same waters and repeated the experiment. She  recorded the results in the table below.  
    

    Sample of water	Volume of soap used  before boiling (cm3)	Volume of soap used after  boiling (cm3)
    A	15	5
    B	15	15

    1. Name the type of water hardness in sample A. Explain. (1mark)
    2. Name two salts that causes water hardness in water sample B. (1mark)
    3. Using a chemical equation, show sodium carbonate can be used to soften water sample B.   (1mark)  
13. 60cm³of oxygen gas diffused through a porous partition in 40 seconds. If 80cm³of gas X diffuses  through the same partition under the same conditions is 75.5 seconds, determine the molecular  mass of gas X. (O=16.0) (3marks)
14. The diagram below represents large scale manufacture of hydrochloric acid. Study it and answer  the questions that follow. 
    
    1. State the function of the glass beads. (1mark)  
    2. Identify gas A. (1mark)  
    3. Explain why gas B is ignited as a jet as shown in the diagram. (1mark)  
15. Below is a structure of an element X. Use it to answer the questions that follow.
     
    1. Name the chemical family to which element X belongs. Give a reason. (2marks)
    2. State the type of bond illustrated above in the structure of element X. (1mark)  
16. The table below shows information of four elements A, B, C and D. Study it and answer the   questions that follow. The letters do not represent the actual symbols of the elements. 
    

    Element	Electronic arrangement	Atomic radius	Ionic radius
    A	2.8.2	0.136	0.065
    B	2.8.7	0.099	0.181
    C	2.8.8.1	0.203	0.133
    D	2.8.8.2	0.174	0.099

    1. Which two elements have similar properties? (1 mark)
    2. Explain why B ionic radius is larger than its atomic radius. (2 marks)
17.  
    1. State the Bronsted – Lowry definition of an acid. (1mark)
    2. With a reason, identify a base in the equation below. (1mark)
       Hph _(aq) + H₂O _(l)  H₃O⁺_(aq) + Ph^-(aq)
    3. Distinguish between strong acid and concentrated acid (1mark)
18. Some average bond energies are given below. 
    

    Bond	Energy(kJ/mol)
    C-C	348
    C-H	414
    Cl-Cl	243
    C-Cl	432
    H-Cl	340

    Calculate the energy change for the reaction below:
    C₂H_6(g) + Cl_2(g)  CH₃CH₂Cl_(g) + HCl_(g) (3marks)
19. The solubility of salt Z at 60⁰C is ^40g/_100g of water and ^48g /_100g of water at 80⁰C .
    1. Define the term solubility (1mark)
    2. 150 g of saturated solution of Z at 80⁰C is cooled to 60⁰C.Calculate the mass of Z that crystallizes  out.         (2marks)
20. Use the table below to answer the questions that follow. 
    

    Substance	A	B	C	D	E
    Symbol	R-COO-Na+	CH2OH   |  CHOH   |  CH2OH		R-COOCH2  |  R- COOCH   |  R- COOCH2	R-OSO3-Na+

    1. Which substances is  
       1. A soapless detergent: ……………………………………………...…………………………(½mark)
       2. An ester………….:…………………………………………..(½mark)
    2. Give name to substance B (1mark)
    3. Write an equation for the reaction between the structure of substance D and Sodium hydroxide solution. (1mark)
21. The figure below shows a simple extraction process of Sulphur 
    
    1. State the name of substances represented by A and B (2marks)
    2. What is the function of the substance represented by C during the extraction process? (1mark)
22. A hydrocarbon X was found to decolourise acidified potassium manganate (VII) solution. When  two moles of X were burnt completely in air six moles of carbon (IV) oxide and six moles of  water were formed.  
    1. Draw the structural formula of X. (1mark)  
    2. State the homologous series to which X belongs. (1mark)
    3. Name a pair of reagents that can be used to prepare X (1mark)
23. The diagram below represents an experiment which was carried out by a student to investigate the  effect of passing an electric current on molten Lead(II) bromide 
    
    1. Molten lead(II) bromide is a binary electrolyte. State the meaning of the term binary electrolyte.  (1mark)
    2. State the observations made at the anode. (1mark)
    3. Write an equation to show what happens at the cathode. (1 mark)
24. The diagram below shows an experiment involving chlorine water. 
    
    1. Describe the confirmatory test for Gas A. (2marks)
    2. Write an equation to show the formation of gas A. (1mark)
25. Study the flow chart below and answer the questions that follow: 
    
    1. Identify
       1. The cation present in solution K (1mark)
       2. The white precipitate L (1mark)
    2. Write down the formula of the complex ion present in the colourless solution M (1mark)
26. Using dot (•) and cross (x) diagram, show the bonding in ;
    1. Phosphonium ion PH⁺₄ ( P=15.0, H=1.0). (2marks)
    2. Sodium oxide (Na = 11, O = 8) (1 mark)
27. Below is a sketch of a reaction profile. 
    
    1. On the diagram show the heat of reaction ∆H (1mark)
    2. State and explain the type of reaction represented by the profile (2marks) 

MARKING SCHEME

1.  
   1. Liegbig condenser 
   2. To measure the temperature at which the liquids boil 
   3. C  
2.  
   • Components are physically combined - composition varies
   • Separated by physical means
   • Components retain their physical and chemical properties
3. Crush the groundnuts using pestle and mortar. Add propanone/acetone as you continue crushing. Decant to obtain oil solution. Leave in the sun for propanone/acetone to evaporate. Wash in distilled water and separate the mixture using a separating funnel
4.  
   1. B. Conducts in molten state but not in solid state 
   2. Metallic bond
   3. Giant covalent/atomic structure/Molecular
5.  
   1. Y, Z, R, X  /    X, R, Z, Y
                         ←Increasing reactivity
   2. Copper/Gold/Silver
6.  
   1. 2.8.6
   2.  
      1. P - 11
      2. Y - 16
   3. P₂Y/Na₂S        rej YP₂/SNa₂ 
7.  
   1. Dehydration
   2. Absorb CO₂ 
   3. P₂bO_(s) + CO_(g) → Pb_(s) + CO_2(g) 
8.  
   1. KNO_3(s) + H₂SO_4(l) → KHSO_4(s) +HNO_3(l) 
   2. Presence of dissolved NO₂. The yellow colour is removed by passing air/oxygen through the acid
9. Add 100cm³ of 2.0M sodium hydroxide to 100cm³ of 1.0M/50cm³ of 2MH₂SO₄ sulphuric (VI) acid ina beaker and stir. Heat the resultant solution to saturation and allow to cool for sodium sulphate crystals to form. Filter out crystals and dry.
10.  
    1.  
       • Hot spiral wire glows red
       • Brown fumes mof NO₂ observed
       • Ammonia burns with a green flame
    2. Catalyses the reaction/increase the reaction rate.  accept catalyst
    3. Platinum/Nichrome. Accept Cu.
11. Mass of H2 = ²/₁₈ × 1.8g = 0.2
    Mass of C = ¹²/₄₄ × 4.4g = 1.2g
    Mass of O2 = 3.1 − (0.2 + 1.2) = 1.7g
                            C              H           O
    Moles        = ^1.2/₁₂      ^0.2/₁       ^1.7/₁₆
    Mole ratio =  ^0.1/_0.1    ^0.2/_0.1     ^0.11/_0.1 
                            1            2            1
    E.F.D = CH₂O
    n = ⁶⁰/₃₀ = 2
    M.F is (CH₂O)₂
    = C₂H₄O₂ 
12.  
    1. Temporary water hardnes, softened removed by boiling
    2. Magnesium chloride/Magnesium Sulphate/ Calcium Chloride.    
       Accept: Nitrates of Mg or Ca        rej.  CaSO₄
    3.  
       • MgCl_2(aq) + Na₂CO_3(aq) → MgCO_3(s) + 2NaCl_(aq) 
       • CaCl_2(aq) + Na₂CO_3(aq) → CaCO_3(s) + 2NaCl_(aq) 
       • MgSO_4(aq) + Na₂CO_3(aq) → MgCO_3(s) + Na₂SO_4(aq) 
13.   
    
    =   2.25   = M_x
       1.2276     32 
    M_x = 2.25 × 32 
              1.12276
         = 64.13
    ALT
    If 60cm³ → 40s
       80cm3 → 80×40
                           60
                  = 53.3333
     (75.5)²  = √^x/₃₂)² 
    (53.33)
    2.004 =  x 
         1      32
    x = 64.13
    M_x = 64.13
14.  
    1. Increase S.A for absorption of HCl(g)
    2. Chlorine/Cl₂ 
    3. Mixture of H₂ and Cl₂ react explosively when heated.
15.  
    1. Alkaline Earth Metals. Has two valence electrons
    2. Metallic
16.  
    1. A and D
    2. Due to increased electron- electron repulsion between the incoming electrons and existing electrons.      Accept shielding effect explained
17.  
    1. An acid is a proton donor
    2. H₂O(l)
       Accept a proton      rej. lone pair of electron donor
    3. Strong acid is one which ionizes fully in water to give more hydrogen ions while concetrated acid is one which has higher proportion of acid mas compared to water
18.  
    
    B.B.E = (1×348) + (6×414) + (1×243)
              = +3075
    BFE =  (1×348) + (5×414) + (1×432) + (1×340)
           = −3190
    ΔH = + 3075 − 3190
          = −115kJ/mol
19.  
    1. Maximum mass of solute that can saturate 100g of water at a given temperature
    2. At 60°C
       if 140g of sln → 40g of salt
           150g → ?
       150 × 40 = 42.86g
           140
       At 80°C
       if 148g of sln → 48g of salt
           150g → ?
       150 × 48 = 48.65g
           148
       Mass of crystals 
       = 48.65 − 42.86 = 5.79g
20.  
    1.  
       1. E/R-OSO₃^-Na⁺
       2. D or 
          R-COOCH₂
           | 
          R- COOCH 
           | 
          R- COOCH₂
    2. Propan -1, 2, 3 - triol     accept Glycerol
    3. R-COOCH₂                                                   CH₂OH
        |                                                                    |
       R- COOCH  + 3NaOH → 3R - COO⁻Na⁺ +  CHOH
        |                                                                     |
       R- COOCH₂                                                  CH₂OH
21.  
    1.  
       
       1. A - Hot compressed air
       2. B - Molten Sulphur & water
    2. To melt Sulphur
22.  
    1.  
       
    2. Alkenes
    3. Propanol and Concentrated Sulphuric (VI) acid/ Aluminium oxide
23.   
    1. An electrolyte that contains one kind of cation and one kind of anion
    2. Brown fumes of bromine gas observed
    3. Pb2⁺_(l) + 2e⁻ → Pb(s)
24.  
    1. Lower/introduce a glowing splint into a gas jar containing gas A; the glowing splint is relit/ rekindled
    2.                     sunlight
       2HOCl_(aq)  2HCl+ O_2(g) 
25.  
    1.  
       1. Pb²⁺
       2. Lead (II) hydroxide/Pb(OH)₂
    2. [Pb(OH)₄]²⁻ 
26.  
    1.  
       
       electron distribution -1
       Charge - 1
    2.  
       
27.  
    1.  
       
    2. Endothermic. Products have more energy/ higher energy compared to reactants