[unphazed]

I need help with these three problems..

1. Methylamine, CH3NH2, is a weak base.

CH3NH2 + H20 ---> <--- (equilibrium sign ) CH3NH3+ + OH-

If the pH of a 0.0065 M solution of the amine is 11.70, what is the value of Kb?

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2. Calculate the hydronium ion concentration and pH for a 0.015 M solution of sodium formate, NaHCO2.

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3. Calculate the hydronium ion concentration and the pH when 50.0 mL of 0.40M NH3 is mixed with 50.0 mL of 0.40M HCl.


thank you very much if you can help, i appreciate it.

[UG]

2. Calculate the hydronium ion concentration and pH for a 0.015 M solution of sodium formate, NaHCO2.

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3. Calculate the hydronium ion concentration and the pH when 50.0 mL of 0.40M NH3 is mixed with 50.0 mL of 0.40M HCl.

Okay, what do you know about pH? What is it exactly? You know that the pH = -log [H₃O⁺] ? The square brackets just means the concentration. Using this, can you calculate the answer to question number 2? Write a balanced equation for when sodium formate is put into water, what happens?

[AWK]

Check concentration in problem #1. It seems to be 0.065 M