Ask Question
8 March, 04:13

how many grams of nahco3 (fm84.007) must be added ro 4.00g of k2co3 (fm 138.206) to give a ph of 10.80 in 500ml of water

+1
Answers (1)
  1. 8 March, 06:00
    0
    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]

    Where [HA] is concentration of acid (HCO₃⁻) and [A⁻] is concentration of conjugate acid (CO₃²⁻).

    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) =

    0.804g of NaHCO₃ you must add
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “how many grams of nahco3 (fm84.007) must be added ro 4.00g of k2co3 (fm 138.206) to give a ph of 10.80 in 500ml of water ...” in 📙 Chemistry if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers