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3 marksMole Concept

CSEC Chemistry · May/June 2012 · Paper 2 · Question 1(a)(v)

A student investigates the effect of particle size on the rate of reaction between calcium carbonate and nitric acid. They weigh 1.8 g of powdered calcium carbonate and 1.8 g of large granules (marble chips), reacting each with excess dilute nitric acid. The volume of gas produced is measured at 10-second intervals for 100 seconds. Table 1 records the gas volume for both reactions. Figure 1 is an incomplete diagram of the apparatus, and Figure 2 shows the graph for powdered calcium carbonate.

Calculate the volume of gas that can be obtained from reacting 1.8 g of calcium carbonate with dilute nitric acid at R.T.P. [1 mole of gas occupies 24 000 cm³ at R.T.P. R.A.M: C = 12; O = 16; Ca = 40]

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Other parts of this question

  1. 1(a)(i)Complete Figure 1 to show how the gas was collected and measured during the experiment.[2 marks]
  2. 1(a)(ii)Using the same axes in Figure 2, plot a graph of the volume of gas produced versus time for the reaction with marble chips. Four of the points have already…[3 marks]
  3. 1(a)(iii)With reference to the volume of gas produced and the slopes along the two curves on the graph, outline ONE similarity and ONE difference in the volume of…[4 marks]
  4. 1(a)(iv)Write a balanced equation for the reaction between calcium carbonate and nitric acid.[2 marks]
  5. 1(a)(vi)From the graph, the total volume of gas produced is 370 cm³. Suggest a possible reason for the difference in your answer obtained in (v) on page 4 and the…[1 mark]
  6. 1(a)(vii)State TWO other factors (than the one given in (vi) above) that can affect the rate of reaction between nitric acid and calcium carbonate.[2 marks]
  7. 1(b)(i)Complete Table 2, row 1, inference (i).[8 marks]
  8. 1(b)(ii)Complete Table 2, row 2, observation (ii).[8 marks]
  9. 1(b)(iii)Complete Table 2, row 3, inference (iii).[8 marks]
  10. 1(b)(iv)Complete Table 2, row 4, inference (iv).[8 marks]
  11. 1(b)(v)Complete Table 2, row 4, observation (v).[8 marks]

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