Name Aalin illes Post lab: Results and Discussion: Green Crystal Lab Section: oo
ID: 1008686 • Letter: N
Question
Name Aalin illes Post lab: Results and Discussion: Green Crystal Lab Section: oo3 Date: 27-1 Analysis Lab Results Part 1: Variable Percent of C20f in your sample Theoretical percent of C20 from Value chemical formula Percent yield Discussion: 1. So two students in the lab forgot to heat up one of their samples. When they started titrating it turned pink with 2.01 mL of KMnO4. They left the flask alone for a few minutes and then the pink color had gone away. They added more KMn04 with the same result. So what purpose do you think heating the solution had on the reaction?? Heohng the 4.st Solenn ans more veach..y 2. Using the chemical reaction in the introduction: a. What element is oxidized? b. What element is reduced? c. What element is the reducing agent? d. What element is the oxidizing agent? e. How many electrons are getting transferred? e)5 electen) List two possible errors that happened in the experiment that caused you not to get 100% on your percent error 3.
Explanation / Answer
Green crystal experiment
1. Heatng the solution ensures all of H2C2O4 in solution has dissolved. If not heated some of the H2C2O4 would remain in an undissolved state.
2. The chemical equation,
2MnO4- + 5C2O4^2- + 16H+ ---> 2Mn2+ + 10CO2 + 8H2O
a. Element oxidized = C
b. Element reduced = Mn
c. Element reducing agent = C
d. Element oxidizing agent = Mn
e. Number of electrons transferred = 5
3. Possoble errors in the experiment would be (a) Not heating the reaction led to undissolved H2C2O4 in solution (b) Losses during filtration of solid crystal.
Discussion
1. Titration curve
a. The titration is between a strong base and an acid
b. titrant being strong acid
c. Volume of titrant added to reach equaivalence point = 43 ml
2. Phenolphthalene remains colorless in acidic solution. So If the solution stays colorless we have added sufficient acid and it helps for stable equivalence point identification.
3. Possible errors (a) If the NaOH solution was kept in open, it absorbs moisture which changes molarity of solution (b) If level of buret is not read properly, introduces error.
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