Introduction:
If we remind in chapter 7, one of the acid - base titrations we executed, was the determination of the percentage purity of a substance. In the demonstration of a alike applicability to redox reactions, we shall in this practical laboratory class attempt to find out the percentage purity of a reductant, FeSO4.7H7O. This we will do via titrating against the standardized solution of potassium permanganate.
Experiment:
Determination of the concentrations of a solution of FeSO4.7H2O using a standard solution of potassium permanganate.
Requirements:
Chemical
Apparatus Quantity
KMnO4 solution
2M H2SO4
FeSO4 .7H2O
Distilled water
Burette (50cm3)
Pipette (25cm3)
Bunsen burner
Wire Gauze
Tripod stand
Clamp
Conical flask (25cm3)
1No
3No
Procedure
1. Rinse the burette (50.0cm3) twice with a few cm3 of KMnO4 solution. Fill the burette with the KMnO4 solution above the Zero mark and drain to this mark, making sure the burette tip is full and any air is ejected within the body of the KMnO4 solution.
2. Pipette out 25.0cm3 of the solution of FeSO4.7H20 into a 250cm3conical flask and add to it 20cm3 of 2moldm-3 sulphuric acid. Heat to between 60 and 80°c.
3. Titrate the hot mixture through KMnO4 from the burette until the solution in the conical flask attains a permanent faint pink colour.
4. Recur the titration using fresh samples each time until at least 2 titrations are within 0.2cm3 accuracy.
5 Record your titre values using the format in earlier experiments and discover the average titre value.
6 From us consequences, determine
a The number of moles of potassium permanganate utilized in the solution.
b The number of moles of the iron compound.
c The concentration in moldm-3 of the iron compound
d The percentage purity of the crystals.
(Mn = 55, K = 39, 0 =16, C=12, H = 1, N =14, 5
S = 32, Fe =56)
Results
Burette Reading
lst titration
2nd titration
3rd titration
Final reading
Initial Readings
Volume of KMnO4
used
Treatment of Results
Step 1: The equation of the reaction
MNO-4(aq) + Fe2+ (aq) + 8H (aq) Mn 2+ (aq ) + 4H2O
Step 2. We shall assume the followings:
1. The permanganate solution used is the standardized solution from the earlier experiment.
2. The amount in moldm-3 of the KMnO4 is 0.002 moldm-3.
3. The average titre value for KMnO4 is Wcm3 .
4. The FeSO4.7H2O solution was prepared in dissolving about 7.6g of the crystals in 250cm3 of solution.
Step3. The number of moles MnO4 = Molarity x (volume).W/ 1000
=W x 0.02 /1000
= M moles
Step4. Find the number of moles of the iron II crystals from the stoichimetric equation of the reaction
1 mole MnO4.5 moles Fe2+(aq )
M mole MnO4 = 5 x M mole Fe2+ (aq)
= 5 M mole in 25cm3
Step 5.The number in moles dm-3 of the Fe2+
= No of mole x 1000 / Volume
= 5M x 1000 / 25
= 200M molesdm-3
Step6. The mass Concentration of the FeSO4.7H2O
Mass concentration = moldin-3 x molar Mass
= 20M x 278gdm-3
= 5560Mgdm-3
= Ngdm-3
Step7. Estimate the percentage purity of the iron salt
Percent purity = mass determined during experiment / Actual mass of iron in 100cm3
= Ngdm-3 x 100 / 4 x 7.6
= q%.
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with an expert at https://www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online chemistry tutoring. Chat with us or submit request at [email protected]
tutorsglobe.com phyllode assignment help-homework help by online leaf modification tutors
tutorsglobe.com larval microbiology assignment help-homework help by online microbiology tutors
tutorsglobe.com non-toxic determinants of virulence assignment help-homework help by online pathogenic attributes of bacteria tutors
Excretory Mechanism tutorial all along with the key concepts of Introduction to Excretory Mechanism, secretion, excretion, elimination and egestion
introduction to petroleum chemistry tutorial all along with the key concepts of crude oil reserves, refining process, fractional distillation, quality of petrol - octane number, conversion processes, petrochemicals
the electron gun structure generates a beam of electrons which is accelerated in the direction of the target.
www.tutorsglobe.com offers answering questions to economic problems associated with unemployment, theory of unemployment theory, economics assignment help-homework help by online tutors
tutorsglobe.com oxygen molecule assignment help-homework help by online molecular orbital energy level diagrams tutors
introduction to organic chemistry tutorial all along with the key concepts of general properties of organic compounds, difference between an organic-an inorganic compound, functional groups
www.tutorsglobe.com free tutorials on role of system analyst, systems analysis skills, systems analyst as a professional, library professionals as system analysts.
tutorsglobe.com management of non-hazardous wastes assignment help-homework help by online waste management tutors
find qualified tutors and top rated roman history and law assignment help service to get customized paper at feasible prices.
tutorial all along with the key concepts of Seismic Reflection Method, Seismic Refraction Methods, Seismic Waves , Types of Elastic Wave, Seismic Velocities, Velocities and the Time-Average Equation, Ray-Path Diagrams , Reflection and Refraction
Our top-rated Plant Breeding Assignment Help tutors can handle all your tasks precisely and assist you to secure top grades at feasible prices!
tutorsglobe.com xenon fluoride compounds assignment help-homework help by online noble gases tutors
1945682
Questions Asked
3689
Tutors
1462513
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!