Abeaker with 1.80×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 6.50 ml of a 0.330 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.

The pH change in 0,206 units

Explanation:

When the acetic acid buffer is at pH 5,000; it is possible to obtain the acetate/acetic acid proportions using Henderson-Hasselbalch formula, thus:

pH = pka + log₁₀ [A⁻]/[HA] Where A⁻ is CH₃COO⁻ and HA is CH₃COOH.

Replacing:

5,000 = 4,740 + log₁₀ [A⁻]/[HA]

1,820 = [A⁻]/[HA] (1)

As buffer concentration is 0,100M:

[A⁻] + [HA] = 0,100 (2)

Replacing (2) in (1)

[HA] = 0,035M

And [A⁻] = 0,065M

As volume is 1,80x10²mL, moles of HA and A⁻ are:

0,180L × 0,035M = 6,3x10⁻³mol of HA

0,180L × 0,065M = 1,17x10⁻²mol of A⁻

The reaction of HCl with A⁻ is:

HCl + A⁻ → HA + Cl⁻

The add moles of HCl are:

0,0065L×0,330M = 2,145x10⁻³ moles of HCl that are equivalent to moles of A⁻ consumed and moles of HA produced.

Thus, moles of HA after addition of HCl are:

6,3x10⁻³mol + 2,145x10⁻³ mol = 8,445x10⁻³ moles of HA

And moles of A⁻ are:

1,17x10⁻²mol - 2,145x10⁻³ mol = 9,555x10⁻³ moles of A⁻

Replacing these values in Henderson-Hasselbalch formula:

pH = 4,740 + log₁₀ [9,555x10⁻³ ]/[8,445x10⁻³ ]

pH = 4,794

The pH change in 5,000-4,794 = 0,206 units

I hope it helps!

the answer is yes

it has kinetic energy

reason

an object has kinetic energy when you stop the force carrying it, the object will stay in motion.

hope this contact me for more questions if you'd like: )