2024 RVHS H2 Chemistry Prelim P4 (QP)

RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION H2 CHEMISTRY 9729 Paper 4 20 AUGUST 2024 2 HOURS 30 MINUTES NAME CLASS 23J ( ) INDEX NO. INSTRUCTIONS TO CANDIDATES DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO. Read these notes carefully. Write your name, class and index number in the spaces at the top of this page. Give details of the practical shift and laboratory where appropriate, in the boxes provided. Write in dark blue or black pen. You may use a 2B pencil for any diagram or graph. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. Shift Laboratory For Examiner’s Use s.f. Units Total 55 _______________________________________________________________________________ This Question Paper consists of 20 printed pages.

River Valley High School Pg 2 of 20 JC 2 H2 Chemistry 9729 2024 Preliminary Examination Paper 4 Answer all the questions in the spaces provided. 1 To determine the percentage by mass of Fe(NO3)2 in a salt mixture FA 1 is a solution containing a salt mixture of two different ionic compounds. One of the compounds is Fe(NO3)2. In this question, you will determine the percentage by mass of Fe(NO3)2 in the mixture by preparing a diluted solution of FA 1 and carry out a titration using potassium manganate(VII). The iron(II) ions, Fe2+, are oxidised by the manganate(VII) ions, MnO4−. 5Fe2+(aq) + MnO4−(aq) + 8H+(aq) → 5Fe3+(aq) + Mn2+(aq) + 4H2O(l) The end-point of the titration occurs when the presence of unreacted MnO4− causes the colour of the solution to become orange. The following reagents are provided. FA 1 is a solution containing 125.4 g dm−3 of the salt mixture in sulfuric acid. FA 2 is 0.0100 mol dm−3 manganate(VII) ions, MnO4−. FA 3 is 1.00 mol dm−3 sulfuric acid, H2SO4. (a) Determining the percentage by mass of Fe(NO3)2 1. Fill a burette with FA 2. 2. Use a pipette to transfer 25.0 cm3 of FA 1 into a 250 cm3 volumetric flask. 3. Make up to the mark with deionised water and label this solution FA 4. Shake to obtain a homogeneous solution. 4. Pipette 25.0 cm3 of FA 4 into a 250 cm3 conical flask. 5. Use the 25.00 cm3 measuring cylinder to add 25.00 cm3 of FA 3 into the conical flask. FA 3 is added in excess. 6. Run FA 2 from the burette into the conical flask. The end-point is reached when the solution changes colour from yellow to orange. 7. Record your titration results , to an appropriate level of precision, in the space provided on the next page. 8. Repeat steps 4 to 7 until consistent titre values are obtained.

River Valley High School Pg 3 of 20 JC 2 H2 Chemistry 9729 2024 Preliminary Examination Paper 4