O Levels Combined Chemistry G3

O Levels G3 Combined Chemistry Paper 1 mock

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1. Lead(IV) chloride has a melting point of -15 °C and boiling point of 50 °C.

Which type of structure do you expect lead(IV) chloride to have?

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2. How many of the following processes will lead to an increase in greenhouse gas emissions?

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3. On adding 50 g of impure limestone, CaCO3 (Mr = 100), to excess hydrochloric acid, 6.0 dm3 of CO2 was evolved at room temperature and pressure.

What is the percentage purity of the limestone?

 

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4. When crude oil is fractionally distilled, which list best describes the mixture of compounds collected at the bottom of the fractionating column?

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5. A paper chromatography experiment was carried out to determine the inks present in a mixture, and the results shown below were obtained.

Which statement about the results is incorrect?

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6. Which equations below represent redox reactions?

1. H+ + OH− → H2O

2. MnO4− + 8H+ + 5e− → Mn2+ + 4H2O

3. Cl2 + 2Br −→ Br2 + 2Cl −

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7. Aqueous hydrogen peroxide decomposes to form water and oxygen gas. Two experiments were carried out to measure the rate of production of oxygen from aqueous hydrogen peroxide.

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8. An element T forms an ion, T2+, which has an electronic arrangement 2.8.8.

Which statement(s) concerning T is/are correct?

I T is an alkali metal.

II T forms a basic oxide with oxygen.

III T is in Period 4 of the Periodic Table.

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9. The structure of brass is shown below.

What is the purpose of adding zinc to copper?

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10. When excess aluminium oxide, Al2O3 was added to a portion of dilute sodium hydroxide. Which of the following correctly describes the pH change and the explanation?

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11. Which statement does not explain why the speed of the reaction between zinc and dilute sulfuric acid increases when the acid is warmed?

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12. Which statement explains why sodium chloride, NaCl, has a lower melting point than magnesium oxide, MgO?

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13. Which compound has the lowest percentage by mass of nitrogen?

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14. The following chemicals are available in the laboratory.

  1. aqueous bromine
  2. Universal Indicator solution
  3. magnesium powder
  4. sodium carbonate

Which of these chemicals can be used to distinguish between propene and propanoic acid?

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15. Which diagram best represents the structure of calcium oxide?

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16. Three elements W, X, Y, and Z have consecutive, increasing proton (atomic) numbers. Element Y exists as a colourless, monatomic gas at room temperature.

Which will be the chemical formula of a compound formed between W and chlorine?

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17. Ammonia and excess carbon dioxide can react to form urea and water in a reaction.

2NH3 + CO2 → CON2H4 + H2O

The percentage yield of this reaction is 80 %.

What is the mass of ammonia required for this reaction to obtain 60.0 g of urea?

[Mr: NH3, 17; CO2, 44; CON2H4, 60; H2O, 18]

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18. An unknown substance X starts melting at –180 °C and finishes melting at –160 °C. What is substance X likely to be?

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19. CH4, H2O and HCl are covalent compounds.

Which atoms in these compounds do not use all their outer shell electrons in bonding?

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20. Which of these Group 1 elements reacts most violently with water?

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