SAJC_H2_CHEM_P2_QNS Prelim

1       [Turn over  1 Answer all the questions Planning (P) Iron(II) sulfate is one of the most readily available sources of iron( II). Hence it is used to make iron supplement tablets to treat anaemia and other iron deficiencies. Women are at a higher risk for iron-deficiency anaemia than men, especially pregnant women. However, excess iron in the body can lead to health problems, and in severe cases, death. The percentage by mass of iron in an iron supplement tablet can be determined by titrating it with acidified potassium manganate( VII). (a) Using the Data Booklet, write an ionic equation for the reaction between iron( II) sulfate and acidified potassium manganate(VII). _________________________________________________________________ [1] (b) If the concentration of a standard solution of potassium manganate( VII) is 0.500 mol dm ‒3, calculate the range of mass of powdered iron supplement tablets needed for a suitable and reliable titration. You may assume that the percentage mass of iron in iron supplement tablets is between 80% to 90%. [2]

2       [Turn over  1 (c) Write a plan for the titration that you would carry out to calculate the mass of iron present in the tablet. You are given a 0.500 mol dm ‒3 standard solution of potassium manganate( VII) and excess powdered iron tablets. You may use the reagents and apparatus normally found in a school or college laboratory. In your plan, you should give: Details, including quantities of all reagents and capacities of apparatus used; The essential details of the titration procedure. _________________________________________________________________  _________________________________________________________________  _________________________________________________________________ _________________________________________________________________  _________________________________________________________________  _________________________________________________________________ _________________________________________________________________  _________________________________________________________________  _________________________________________________________________ _________________________________________________________________  _________________________________________________________________  _________________________________________________________________ _________________________________________________________________  _________________________________________________________________  _________________________________________________________________ _________________________________________________________________  _________________________________________________________________  _________________________________________________________________ _________________________________________________________________  ____________