Hi I could really use some help with this pre lab. I have already asked this que
ID: 783708 • Letter: H
Question
Hi I could really use some help with this pre lab. I have already asked this question on cheeg without any success so if you can help me solve these missing parts I will re ask this question for another 3000 pts if my website accepts your answers. But more importantly I would like to understand what you did.
https://www.dropbox.com/s/pauj005wkcby0m1/probsetH2O2.pdf
i have done most of the work i just need help solving parts: C, E, F, I.
i found that:
Method 1
A) Molarity of MnO4- solution ...0.0264 M
B) Molarity of HOOH in the unknown...1.32 M
Method 2
C) Partial pressure of O2 collected.........??? mmHg
Correct for water vapor pressure which at 21 C or 296.15 K is 18.650 mmHg
D) Volume of O2 gas collected...53.3 mL
E) Milimoles of O2 generated.........??? mmol
The ideal gas law is PV=nRT
R, the Gas Constant, has a value of 0.08206 L atm / mol K . Use the correct units!
F) Molarity of HOOH in unknown.........??? M
Molarity = mol/L = mmol/mL
Method 3
G) Absorbance of the STANDARD...0.324
H) Absorbance of the UNKNOWN...0.404
I) Molarity of original UNKNOWN.........??? M
A mole of Iodate ion produces 3 moles of iodine.
One mL of your UNKNOWN was diluted to 250 mL
Thanks for your help in advance!
Explanation / Answer
since vapor pressure of water at the given temperature= 18.65mm. and total pressure 766mm. therefore partial pressure of oxygen = 766-18.65 = 747.35mm ( answer of c)......... vol of oxygen collected = (263.62-210.52)/0.996 = 53.3 mm (answer for d) ...... no of moles of oxygen = (PV)/(R*T) =(747.35/760)(53.3/1000)/(0.0821*294) = 2.17mmole (answer for e) .....molarity of H2O2 = ( 2* moles of O2 produced)/4.9ml = (2*2.17)/4.9 = 0.886