chem ch 16 - Ch 16 Acid-base equilibria Whats the pH of 0.200M acetic acid Ka for acetic acid = 1.8 x 10-5 pH = Whats the pH of a solution that is made

chem ch 16 - Ch 16 Acid-base equilibria Whats the pH of...

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Ch 16: Acid-base equilibria What’s the pH of 0.200M acetic acid? K What’s the pH of a solution that is made of 0.200M acetic acid and 0.100M sodium acetate? Remember that salts are 100% dissociated into their ions.pH=Le Chatelier: in the presence of a common ion(A-), theWhat is the pH of 1.50M pyridine, C5H5N? - A- What is the pH of a solution that is 1.50M in pyridine and 1.500M in pyridinium chloride, C5H5NHCl? - What is the pH of a 1.0 x 10-8M sol’n of HCl?
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. and 1 10 How do buffers work? HA + A- + Have 100mL of 3.6x10-5M HCl; pH = 4.44 What if had a buffer sol’n--what happens when add acid and base to the buffer soln? Practice exercise: Calc the pH of the 0.30 M NH3/ 0.36 M NH4Cl buffer. What is the pH after the addition of 20.0 mL of 0.050 M NaOH to 80.0 mL of the buffer? What is the pH after the addition of 20.0 mL of 0.050 M HCl to 80.0 mL of the buffer?
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16.18 Calc the pH of 1.00 L of the buffer 1.00 M CH 3 COONa/1.00 m CH 3 COOH. What is the pH after add 0.08 mol NaOH Are these buffers: KOH/KCl NaOH/HCl NH 3 /NH 4 Cl NaF/HF Na 2 HPO4/NaH 2 PO4 NaOH/HF NH 3 /HCl HF/HCN CO 2 / HCO 3 - What mass of C 6 H 5 COONa (sodium benzoate) do you need to add to 400. mL of 0.500M C 6 H 5 COOH (benzoic acid) to make a buffer of pH=4.540? K a = 6.5x10 -5 for the acid. 16.15: The pH of a sodium acetate- acetic acid buffer is 4.50. Calculate the ratio [CH 3 COO-]/[CH 3 COOH]. Henderson-Hasselbalch HA H + + A- K a = [H + ][A-]/[HA] take log of both sides logK a = log[H + ] + log{[A-]/[HA]} multiply thru by -1 and rearrange pH =pK a + log{[A-]/[HA]} or pH = pK a + log {[conj base]/[acid]} pK a + pK b = 14 or K a K b = 1x10 -14 for any conj acid/base pair For buffers ratio of [conj base]/[acid] btn 0.1 and 10 So pH = pK a + log {[conj base]/[acid]} or pH = pK a good for preparing a buffer of a desired pH.
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