Acids ph buffers A2 chemistry
Using the post it notes write down the name of the species and whether each species round
the room is an acid, base or alkali
0.8L of 1M ethanoic acid reacted was titrated with 0.2L 1M NaOH. Calculate the pH of the
solution. Ka = 1.76 x 10-5
Acid moles [HA] H+ Base moles
Initial
change
Equilibrium
Step 1. Work out moles of HA at start
Step 2. Work out moles of base at start
Step 3. Work out moles of HA that reacted with base – this is moles H+
Step 4. Minus moles of neutralised HA from initial acid to get the moles of HAKa x [HA] = [H+]2Step 5. Use equilibrium concentrations and put them in this equation
Step 6. use pH = -log [H+]
0.25L of 1M ethanoic acid reacted was titrated with 0.25L 1M Ca(OH)2. Calculate the pH of the
solution. Ka = 1.76 x 10-5
Acid moles [HA] H+ Base moles
Initial
change
Equilibrium
Step 1. Work out moles of HA at start
Step 2. Work out moles of base at start
Step 3. Work out moles of HA that reacted with base – this is moles H+
Step 4. Minus moles of neutralised HA from initial acid to get the moles of HAKa x [HA] = [H+]2Step 5. Use equilibrium concentrations and put them in this equation
Step 6. use pH = -log [H+]
0.3L of 1M Methanoic acid reacted was titrated with 0.7L 1M Ca(OH)2. Calculate the pH of the
solution. pKa = 3.77Acid moles [HA] H+ Base moles
Initial
change
Equilibrium
Step 1. Work out moles of HA at start
Step 2. Work out moles of base at start
Step 3. Work out moles of HA that reacted with base – this is moles H+
Step 4. Minus moles of neutralised HA from initial acid to get the moles of HAKa x [HA] = [H+]2Step 5. Use equilibrium concentrations and put them in this equation
Step 6. use pH = -log [H+]