Problem 1,2, and 3 please. Calculate the quantity of KMnO_4 needed to prepare 35
ID: 1005672 • Letter: P
Question
Problem 1,2, and 3 please.
Calculate the quantity of KMnO_4 needed to prepare 350 mL of 0.004 M solution. Determine the weight of Fe(NH_4)_2(SO_4)_2 middot 6H_2O which is required to react completely with 20.0 mL of 0.004 M KMnO_4. Answer the following questions in your notebook before arriving at the laboratory. Potassium dichromate reacts with potassium oxalate according to the equation: 3K_2C_2O_4(aq) + K_2Cr_2O_7(aq) + 8H^+(aq) rightarrow 6CO_2(g) + Cr_2O_3(s) + 4H_2O(l) + 8K^+(aq) When 0.2016 g of anhydrous potassium oxalate was dissolved in dilute acid and titrated with a solution of potassium dichromate, the volume required to reach the endpoint was 17.97 mL. Calculate the concentration of the potassium dichromate solution. 1.145 g of sodium chloride and 1.285 times 10^-2 mol of sodium peroxydisulfate (Na_2S_2O_8) were mixed together and ground in a mortar and pestle. Calculate the percent by mass of sodium chloride in the resulting mixture. The potassium dichromate solution from question 1 was used to titrate a sample known to contain a mixture of sodium sulfate and sodium oxalate. The dichromate does not react with sodium sulfate. 0.2487 g of the mixture was dissolved in dilute acid and titrated with the potassium dichromate solution to an endpoint at 12.61 mL. Calculate the percent by mass of sodium oxalate in the unknown mixture.Explanation / Answer
3K2C2O4 + K2Cr2O7 + 8 H+ ------> 6 CO2 + Cr2O3 + 4H2O + 8K+
number of moles of K2C2O4 = 0.2016/184.23 = 1.0943 * 10^-3
3 moles of K2C2O4 requires 1 mole of K2Cr2O7
1.0943 * 10^-3 moles of K2C2O4 requires 1.0943 * 10^-3/3 = 3.647 * 10^-4moles
concentration of K2Cr2O7 = 3.647*10^-4/17.97*1000 = 0.02029 M
mass of Na2S2O8 = 1.285 * 10^-2 * 238.1 = 3.0596 g
mass of NaoH = 1.145 g
percentage mass = 1.145/(1.145 + 3.0596)*100 = 27.23%
number of moles of K2Cr2O7 = 12.61 * 0.02029/1000 = 2.559 * 10^-4moles
number of moles of Na2C2O4 required = 3 * 0.2559 moles = 7.677 * 10^-4
mass of Na2C2O4 = 7.677 * 10^-4 * 134 = 0.1029
pecentage of mass = 0.1029/0.2487*100 = 41.37%
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.