Chemistry - Grade 12 -2023 G.C

Grade 12 students can now access their exam results by visiting the Educational Assessment and Examination Services (EAES) website.


75. Which one of the following explains the determination of the cell potential of Zn-Cu cell using voltmeter?

  1. After the experiment the mass of zinc is increased.
  2. Each U-tube served as a salt bridge that can be filled with saturated KCI.
  3. In the Zn half- cell, Zn metal will be dipped in CuSO4 solution.
  4. In the Cu half-cell, Cu metal will be dipped in ZnSO4 solution.


76. The rate law for: 1 is rate= 2.
The accepted mechanism for the reaction is3
Why DOES NOT H2O appear in the rate law? Beacuse

  1. water is missing in the rate determining step.
  2. water exists in the liquid state in the reaction.
  3. water is an intermediate species.
  4. water is a catalyst in the reaction.


77. Which type of substances has the following general formula? (R1, R2 and R3 hydrocarbon groups.)
1

  1. Fatty acids
  2. Alcohols
  3. Fats
  4. Carboxylic acids


78. The rate law for this reaction CO(g)+NO2(g) → CO2(g)+NO(g) is rate = k [NO2]2.
Which one of the following could be a plausible mechanism for the reaction?

  1. NO2(g)+NO2(g)→NO3(g)+NO2(g)[fast]
    NO3(g)+CO(g)→NO2(g)+CO2(g) [slow]" >NO2(g)+NO2(g)→NO3(g)+NO2(g)[fast]
    NO3(g)+CO(g)→NO2(g)+CO2(g) [slow]
  2. NO3(g)+NO(g)→NO2(g)+NO2(g)[slow]
    NO2(g)+CO2(g)→NO3(g)+CO2(g)[fast]" >NO3(g)+NO(g)→NO2(g)+NO2(g)[slow]
    NO2(g)+CO2(g)→NO3(g)+CO2(g)[fast]
  3. NO3(g)+NO(g)→NO2(g)+NO2(g)[slow]
    NO3(g)+CO(g)→NO2(g)+CO2(g)[fast]" >NO3(g)+NO(g)→NO2(g)+NO2(g)[slow]
    NO3(g)+CO(g)→NO2(g)+CO2(g)[fast]
  4. NO2(g)+NO2(g)→NO3(g)+NO(g)[slow]
    NO3(g)+CO(g)→NO2(g)+CO2(g)[fast]" >NO2(g)+NO2(g)→NO3(g)+NO(g)[slow]
    NO3(g)+CO(g)→NO2(g)+CO2(g)[fast]


79. The speed with which a solute goes into solution is

  1. extent of dissolution
  2. rate of dissolution
  3. heat of solution
  4. degree of solvation


We have provided these questions from previous years grade 12 Ethiopian Secondary School Leaving Certificate Examination (ESSLCE) exams with the sole purpose of assisting students in their studies and preparations for upcoming exams. Please be aware that these questions are not indicative of future exam content. Good luck with your studies!

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