Upload
voncold
View
213
Download
1
Embed Size (px)
DESCRIPTION
er
Citation preview
1a) Fe2+¿+MnO4→Fe3 +¿+Mn
2+¿+H 2O ¿¿¿
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:✍
Fe2+¿→Fe3+¿+e−¿¿¿ ¿……………………….×5
MnO4−¿+8 H +¿+5 e−¿→Mn
2+¿+4 H2O¿¿¿ ¿
5 Fe2+¿→5 Fe3+¿+5 Fe−¿¿¿¿
5MnO4−¿+8 H+¿+5e−¿→Mn
2+¿+4H 2O ¿¿¿ ¿
5 Fe2+¿+MnO4−¿+8H2+¿→ 5Fe3+¿+Mn
2+¿+ 4H 2O¿¿ ¿¿¿
b) 5 moles of Fe2+¿¿ reacted with 1 mole of MnO4−¿ ¿ions
c) number of moles of Fe2+¿¿that react with 25cm3 of 0,04 KMnO4
number of moles=concentration×volume
number onmoles=25
1000×0.04=0.001moles
since the ratio is 1:5 Number of moles of Fe2+¿¿
=0.001 × 5 = 0,005 moles
d) The mass of Fe2+¿¿ which are in 200cm3 of the original solution 20cm3 ¿5×10−3
200cm3 ¿more
0.2
0.02×5×10−3=0.05
Therefore mass =number of moles×molecularmass 5×10−2×56 = 2.8g
1e) percentage by mass of iron in impure iron (ɪɪ) salts. Since 2.8g reacted
2.8g10g
×100
=28%