Chemistry problems!Help!

题目

Chemistry problems!Help!
1.Calculate the pH when we add 0.001 mole of HAc to 0.02 mole of NaAc and bring the volume up to 100ml with pure water.
HAc ↔ H+ + Ac− pKa = 4.76
2.Consider the following two systems:
(a) 0.1 litre of pure water at pH 7.0
(b) 0.1 litre of 0.1M phosphate buffer at pH 7.2
H2PO4 ↔ HPO42− + H+ pKa = 7.2
If we add 10ml of 0.01 M HCl to each,what will be the pH in each solution.
p/s:Solve the questions,not translate it for me!Thanks!
I need the answer in English,please..Help!

答案

1.suppose [H+]=x mol/Lbefore ionization[HAc]=0.01mol/L [Ac-]=0.2mol/LHAc ↔ H+ + Ac− before 0.01 0 0.2after 0.01-x x 0.2+xthus -lg[(0.2+x)*x/(0.01-x)]=4.76note that x is quite smalltherefor...