MJC_H2_CHEM_P4_Qns.pdf - 2017 MJC H2 Chemistry Prelim Paper...

Info icon This preview shows pages 1–5. Sign up to view the full content.

1 MJC Prelim 2017 H2 Chemistry 1 Magnesium carbonate is a white solid that is readily found in nature. In this experiment, you will determine the percentage purity of a sample impure magnesium carbonate. FA 1 is a sample of impure magnesium carbonate. You may assume that only the magnesium carbonate present in the sample will react with the acid. You will first dissolve FA 1 in excess hydrochloric acid. MgCO 3 (s) + 2HC l (aq) MgC l 2 (aq) + H 2 O( l ) + CO 2 (g) The resulting solution will then be titrated using sodium hydroxide. You may assume that no compounds present in FA 1 will react with the sodium hydroxide. NaOH(aq) + HC l (aq) NaC l (aq) + H 2 O( l ) FA 1 is impure magnesium carbonate. FA 2 is 2.0 mol dm -3 hydrochloric acid, HC l . FA 4 is 0.20 mol dm -3 sodium hydroxide, NaOH. methyl orange indicator (a) Procedure Preparation of standard solution 1. Fill a burette with FA 2 . 2. Run between 47.50 and 48.50 cm 3 of FA 2 into a 250 cm 3 beaker. 3. Record your burette readings and the volume of FA 2 in the space below. 4. Weigh accurately about 2.0 g of FA 1 in a weighing bottle. 5. Transfer the FA 1 from the weighing bottle as fully as you can into the beaker containing FA 2 . 6. Reweigh the weighing bottle and record all masses in the space below. 2017 MJC H2 Chemistry Prelim Paper 4
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.