Answer:
0.804g of NaHCO₃ you must add
Explanation:
pKa of HCO₃⁻/CO₃²⁻ is 10.32.
It is possible to find pH of a buffer by using H-H equation, thus:
pH = pka + log [A⁻] / [HA]
<em>Where [HA] is concentration of acid (HCO₃⁻) and [A⁻] is concentration of conjugate acid (CO₃²⁻).</em>
Moles of CO₃²⁻ = K₂CO₃ are:
4.00g ₓ (1mol / 138.206g) = 0.0289 moles CO₃²⁻
Replacing:
10.80 = 10.32 + log [0.0289] / [HCO₃⁻]
[HCO₃⁻] = 0.009570 moles you need to add to obtain the desire pH
As molar mass of NaHCO₃ is 84.007g/mol, mass of NaHCO₃ is:
0.009570 moles ₓ (84.007g / mol) =
<h3>0.804g of NaHCO₃ you must add</h3>
Answer:
1.784 g
Explanation:
The equation of the reaction is;
NaOH(aq) + KHC8H4O4(aq) --------> KNaC8H4O4(aq) + H2O(l)
Number of moles of NaOH reacted = 17.47/1000 * 0.5000 M
Number of moles of NaOH reacted =8.735 * 10^-3 moles
From the reaction equation;
1 mole of NaOH reacted with 1 mole of KHC8H4O4
Hence, 8.735 * 10^-3 moles of NaOH reacts with 8.735 * 10^-3 moles of KHP.
So,
Mass of KHP reacted = 8.735 * 10^-3 moles * 204.2 g/mol = 1.784 g
