This is a workaholic problem.
1. Determine empirical formula.
2. Determine molar mass
3. Determine molecular formula.
4. Determine the molarity of the maleic acid in the titration experiment.
5. Determine Ka1.
And you need help with which one. Show your work for what you have and I can help you through.
Item 1
Maleic acid is a carbon-hydrogen-oxygen compound used in dyeing and finishing fabrics and as a preservative of oils and fats. •In a combustion analysis, a 1.054-g sample of maleic acid yields 1.599 g of CO2 and 0.327 g of H2O.
•When 0.609 g of maleic acid is dissolved in 25.00 g of glacial acetic acid, the freezing point drops by 0.82 ∘C. Maleic acid does not ionize in glacial acetic acid, which has a freezing-point depression constant of Kf=3.90 ∘C/m.
•In a titration experiment, a 0.4250-g sample of maleic acid is dissolved in water and requires 34.03 mL of 0.2152 M KOH for its complete neutralization.
•The pH of 0.215 g of maleic acid in 50.00 mL of aqueous solution is found to be 1.80.
Determine the first ionization constant, Ka1, of maleic acid
5 answers
I have the molecular formula C4H4O4. and I know that there is 2 ionisable H ions but I don't know where to go from there.
So you have 1,2,3.
4. C4H4O4 which since it is diprotic we can write H2M.
H2M + 2KOH ==> 2H2O + K2M
mols KOH = M x L = ?
mols H2M = 1/2 that from the coefficients
M H2M = mols H2M/L H2M. That give you the M of the solution but I don't understand why this information is needed.
5. M H2M = grams/molar mass = ? which I will call Y, whatever that is. Also convert pH to H^+
.....H2M ==> H^+ + HM^-
I.....Y......0.....0
C.....-x.....x.....x
E......Y-x...x.....x
k1 = (H^+)(HM^-)/(HM)
You know H^+ (from pH) and HM and HM, solve for k1.
Post your work if you get stuck.
4. C4H4O4 which since it is diprotic we can write H2M.
H2M + 2KOH ==> 2H2O + K2M
mols KOH = M x L = ?
mols H2M = 1/2 that from the coefficients
M H2M = mols H2M/L H2M. That give you the M of the solution but I don't understand why this information is needed.
5. M H2M = grams/molar mass = ? which I will call Y, whatever that is. Also convert pH to H^+
.....H2M ==> H^+ + HM^-
I.....Y......0.....0
C.....-x.....x.....x
E......Y-x...x.....x
k1 = (H^+)(HM^-)/(HM)
You know H^+ (from pH) and HM and HM, solve for k1.
Post your work if you get stuck.
I still cant figure this out.
For 4, what is your problem? What have you done and what don't you understand.
For 5, what is your problem? What have you done? Where are you stuck? What do you not understand.?
Still can't figure it out doesn't help me know what's wrong.
For 5, what is your problem? What have you done? Where are you stuck? What do you not understand.?
Still can't figure it out doesn't help me know what's wrong.
4 answers