AP Chemistry

posted by .

CH3NH2(aq)+H2O(l)=>CH3NH3+(aq)+OH-(aq) Kb=4.4 x 10^-4
Methylamine, CH3NH2, is a weak base that reacts with water according to the equation above. A student obtains a 50.0 mL sample of a methylamine solution and determines the pH of the solution to be 11.77.
(a) Write the expression for the equilibrium constant, Kb, for methylamine.
(b) Calculate the molar concentration of OH- in the 50.0 mL sample of the methylamine solution.
(c) Calculate the initial molar concentration of CH3NH2(aq) in the solution before it reacted with water and equilibrium was established.
The 50.0 mL sample of the methylamine solution is titrated with HCl solution of unknown concentration. The equivalence point of the titration is reached after a volume of 36.0 mL of the HCl solution is added. The pH of the solution at the equivalence point is 5.98.
(d) Write the net-ionic equation that represents the reaction that takes place during the titration.
(e) Calculate the concentration of the HCl solution used to titrate the methylamine.
(f) using the axes provided, sketch the titration curve that results from the titration described above. On the graph, clearly label the equivalence point of the titration.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. CHEMISTRY

    Methylamine (CH3NH2) forms hydroxide ions in aqueous solution. Why is methylamine a Brønsted-Lowry base but not an Arrhenius base?
  2. CHEIMSRTY

    Methylamine (CH3NH2) forms hydroxide ions in aqueous solution. Why is methylamine a Brønsted-Lowry base but not an Arrhenius base?
  3. Chemistry

    A few questions I don't really get and need to see the work for A 50.0 mL sample of 0.55 M benzoic acid, C6H5COOH, a weak monoprotic acid, is titrated with 0.51 M NaOH. Calculate the pH at the equivalence point. Ka of C6H5COOH = 6.5 …
  4. college chemistry

    Calculate the [CH3NH3+] of a 7.02×10-3 M solution of the weak base CH3NH2 (make an approximate calculation assuming that initial concentration is equal to the equilibrium concentration). Round your answer to 3 significant digits. …
  5. College Chemistry Help Please!

    what is the pH of a solution that is 0.200 M in methylamine, CH3 NH2 CH3NH2+ H20<======> CH3NH3+ + OH- Kb= 4.2 x 10 ^-4
  6. Chemistry

    A solution is prepared by diluting 65.0 mL of 0.175 M methylamine, CH3NH2, to a total volume of 225 mL. Calculate the pH of the diluted solution. Kb (CH3NH2) = 4.40 x 10-4
  7. chemistry

    What ratio [CH3NH3+]/[CH3NH2] is needed to prepare a buffer solution with a pH of 8.60 from methylamine, CH3NH2, and methylammonium chloride, CH3NH3Cl?
  8. Analytical Chemistry

    Calculate the pH at the equivalence point for the titration of 0.160 M methylamine (CH3NH2) with 0.160 M HCl. The Kb of methylamine is 5.0× 10–4. Methylamine is a weak base and reacts with HCl to give the methylammonium ion. HCl …
  9. chemistry

    CH3NH2(aq)+H2O(l)=>CH3NH3+(aq)+OH-(aq) Kb=4.4 x 10^-4 Methylamine, CH3NH2, is a weak base that reacts with water according to the equation above. A student obtains a 50.0 mL sample of a methylamine solution and determines the pH …
  10. chemistry

    Consider a buffer solution consisting of CH3NH3Cl and CH3NH2. Which of the following statements are true concerning this solution?

More Similar Questions