You need to prepare 100.0 mL of a pH 4.00 buffer solution using 0.100 M benzoic acid (p K a = 4.20 ) (pKa=4.20) and 0.140 M 0.140 M sodium benzoate. How many milliliters of each solution should be mixed to prepare this buffer? benzoic acid: mL mL sodium benzoate: mL

68.9mL of benzoic acid

31.1mL of sodium benzoate

Explanation:

Using Henderson-Hasselbalch formula:

pH = pka + log [Benzoate] / [Benzoic acid]

Where [Benzoate], [Benzoic acid] could be seen as moles of each compound.

4.00 = 4.20 + log [Benzoate] / [Benzoic acid]

0.631 = [Benzoate] / [Benzoic acid]

0.631 [Benzoic acid] = [Benzoate] (1)

0.1000L = [Benzoic acid] / 0.100M +  [Benzoate] / 0.140M (2)

Replacing (1) in (2):

0.1000L = [Benzoic acid] / 0.100M +  0.631 [Benzoic acid] / 0.140M

0.1000L = 14.5 [Benzoic acid]

6.893x10⁻³ = Moles of benzoic acid

Replacing this value in (1):

4.350x10⁻³ = Moles of sodium benzoate

Converting these moles in volume using molar concentration:

6.893x10⁻³mol ₓ (1L /0.1mol ) = 0.0689L ≡ 68.9mL of benzoic acid.

4.350x10⁻³mol ₓ (1L /0.14mol ) = 0.0311L ≡ 31.1mL of sodium benzoate.

I hope it helps!

no, i was listening to water by schoolboy q while and i saw this question

explenation:

water isn't wet. wetness is a description of our experience of water; what happens to us when we come into contact with water in such a way that it impinges on our state of being. we, or our possessions, 'get wet'. a less impinging sense experience of water is that it is cold or warm, while visual experience tells us that it is green or blue or muddy or fast-flowing. we learn by experience that a sensation of wetness is associated with water: 'there must be a leak/i must have sat in something.'

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.