Describe how you would prepare 100 ml of a 0.050 m sodium citrate tribasic buffer to a ph of 6. this method is accomplished by preparing a solution of a weak species base and then adding the appropriate strong species 0.5 m hcl to get to the desired ph. what amount of mass or volumes should you add?

To prepare 100 mL of a 0,050M sodium citrate tribasic buffer to a pH of 6 you need to add 7,16 mL of 0,5M HCl, 1,4705 g of sodium citrate tribasic dihydrate and complete 100 mL with water.

Explanation:

The acid equilibrium of sodium citrate tribasic buffer is:

citrate dibasic⁻² ⇄ citrate tribasic⁻³ + H⁺ pka = 6,4

Using Henderson-Hasselbalch formula:

pH = pka + log₁₀

6,0 = 6,4 + log₁₀

0,3981 = (1)

You need to add 0,1L× 0,050M = 0,0050moles of sodium citrate:

0,0050 moles = Citrate tribasic + Citrate dibasic (2)

Replacing (2) in (1)

Citrate dibasic: 3,58x10⁻³ moles

Thus,

Citrate tribasic: 1,42x10⁻³ moles

Citrate tribasics reacts with HCl thus:

Citrate tribasic⁻³ + HCl → Citrate dibasic⁻² + Cl⁻

Thus, you need to add 5x10⁻³moles of sodium citrate tribasic and 3,58x10⁻³ moles of HCl:

5x10⁻³moles of sodium citrate tribasic× = 1,4705 g of sodium citrate tribasic dihydrate -commercial reactant-

3,58x10⁻³ moles of HCl÷ 0,5 M = 7,16x10⁻³ L ≡ 7,16 mL of 0,5M HCl

Thus, to prepare 100 mL of a 0,050M sodium citrate tribasic buffer to a pH of 6 you need to add 7,16 mL of 0,5M HCl, 1,4705 g of sodium citrate tribasic dihydrate and complete 100 mL with water.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

the answer is minerals.