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2 marksMole Concept

CSEC Chemistry · January 2002 · Paper 2 · Question 1(a)(iii) [P2]

Reaction of magnesium with dilute hydrochloric acid in a flask connected to a 100 cm³ syringe (Figure 1).

How many moles of hydrogen were collected at rtp? (1 mol of any gas at rtp has a volume of 24 dm³.)

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Other parts of this question

  1. 1(a)(i)Explain what is meant by a 'normal salt' and an 'acid salt'.[2 marks]
  2. 1(a)(ii)Describe a suitable test to distinguish between a normal salt and an acid salt.[2 marks]
  3. 1(b)(i)In preparing samples of barium sulphate and zinc sulphate, discuss the possibilities of using the action of acid on the metal.[4.5 marks]
  4. 1(b)(ii)In preparing samples of barium sulphate and zinc sulphate, discuss the possibilities of using titration using acid and alkali.[4.5 marks]
  5. 1(c)(i)Giving full experimental details, outline a suitable method for preparing a sample of dry barium sulphate, specifying the reactions to be used.[2 marks]
  6. 1(c)(ii)Provide a description of the method for preparing the dry barium sulphate sample.[3 marks]
  7. 1(c)(iii)Write all relevant equations for the preparation of barium sulphate.[2 marks]
  8. 1(a)(i) [P2]Write an ionic equation for the reaction taking place in the flask.[2 marks]
  9. 1(a)(ii) [P2]What is the volume of hydrogen collected in the syringe?[1 mark]
  10. 1(a)(iv) [P2]How many moles of magnesium were used up?[1 mark]
  11. 1(a)(v) [P2]Explain why the volume of gas in the syringe is the volume of hydrogen produced, although air was already in the flask.[1 mark]
  12. 1(a)(vi) [P2]Select the apparatus for drying the gas by circling X, Y or Z, and select the apparatus to collect the dried gas by circling P, Q or R.[2 marks]
  13. 1(a)(vii) [P2]Suggest a reason why some gas should be allowed to escape before collecting dry hydrogen.[3 marks]
  14. 1(b)(i) [P2]Read off the height of the precipitate present in EACH test tube in millimetre and record it on the table.[4 marks]
  15. 1(b)(ii) [P2]Plot the results on the grid provided and draw the line of best fit.[6 marks]
  16. 1(b)(iii) [P2]In which test tube are the ions of neither solution M nor N in excess?[1 mark]
  17. 1(b)(iv) [P2]Name the ions present in the SOLUTION in Test tube 6 on page 4.[3 marks]
  18. 1(b)(v)a)5.0 cm³ of solution N completely reacts with ______ cm³ of Solution M.[1 mark]
  19. 1(b)(v)b)1 mole of lead ions completely reacts with ______ moles of iodide ions.[1 mark]
  20. 1(b)(vi) [P2]Use the answer in (v) b) to write the equation for the reaction taking place between lead ions and iodide ions.[2 marks]

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