DEPARTMENT OF TEACHER EDUCATION

BELVEDERE TECHNICAL TEACHERS’ COLLEGE

DEPARTMENT OF NATURAL SCIENCES

�SCIENCESECTION�

DIPLOMA IN EDUCATION (SECONDARY LEVEL)

NAMES: MAKWANA ADMIRE CANDIDATURE: 15/090 CLASS: DE1-POST ‘O’ SUBJECT: CHEMISTRY LECTURER: Ms. MADONDO TOPIC: REDOX TITRATION DATE: 27/10/15

INTERNAL MARK: COMMENT: ✍ MODERATOR’S MARK: COMMENT: ✍ EXTERNAL MARK: COMMENT:✍

 

 

 

                                                                                                         

        

 

   1a)  MnO  → Fe Mn H OFe2+ +   4

3+ +   2+ +   2            ………………………. → Fe eFe2+ 3+ +   − 5×        8H 5e  → Mn 4H OMnO4

− +   + +   − 2+ +   2            → 5Fe5Fe2+ 3+ + 5Fe−         → Mn O5MnO4

− + 8H+ + 5e− 2+ + 4H2         8H → 5Fe O5Fe2+ +MnO4

− +   2+ 3+ +Mn2+ + 4H2   b) 5 moles of   reacted with 1 mole of  ionsFe2+  MnO4

−   c) number of moles of  that react with 25cm3  of 0,04  Fe2+ KMnO4        umber of moles oncentration×volumen = c      umber of moles ×0.04  .001molesn = 25

1000 = 0      since the ratio is 1:5   Number of moles of Fe2+  =0.001   5 = 0,005 moles×   d) The mass of   which are in 200cm3 of the original solutionFe2+     20cm3  ×10= 5 −3     200cm3  ore= m       ×5×10 .050.2

0.02−3 = 0  

   Therefore mass =number of moles molecular mass×                                   ×565×10−2                              = 2.8g  1e)  percentage by mass of iron in impure iron (ɪɪ) salts.           Since 2.8g reacted          ×10010g

2.8g         =28%