Chemistry, 07.10.2019 23:00 crazymadhatter0

Buffer capacity is a measure of a buffer solution's resistance to changes in ph as strong acid or base is added. suppose that you have 185 ml of a buffer that is 0.400 m in both acetic acid (ch3cooh) and its conjugate base (ch3coo−) . calculate the maximum volume of 0.180 m hcl that can be added to the buffer before its buffering capacity is lost.

Answers: 1

Show answers

Answers

Answer from: bgallman153p71edg

Explanation:

It is given that 185 ml of buffer solution is 0.40 M $CH_{3}COOH$ and $CH_{3}COO^{-}$ .

Now, according to the Handerson equation,

pH = $pK_{a} + log \frac{CH_{3}COO^{-}}{CH_{3}COOH}$

It is known that $pK_{a}$ value of acetic acid is 4.76.

pH = $pK_{a} + log \frac{CH_{3}COO^{-}}{CH_{3}COOH}$

= $4.76 + log \frac{0.40}{0.40}$

= 4.76

If pH of a buffer changes by 1 unit then it means the buffering capacity is lost.

Hence, when HCl is being added it reacts with $CH_{3}COO^{-}$ and gives $CH_{3}COOH$ . So, with increase in $[CH_{3}COOH]$ the log term gives a negative value. This means that new pH will be less than 4.76.

Therefore, calculate the concentration when pH = 3.6.

3.76 = 4.76 + $log \frac{CH_{3}COO^{-}}{CH_{3}COOH}$

$\frac{CH_{3}COO^{-}}{CH_{3}COOH}$ = 0.1 ....... (1)

Now, we assume that the moles of acid added or change in moles is x. Therefore, moles of acetic acid and conjugate base present are as follows.

No. of moles = Molarity × Volume

= 0.40 × 185 ml

= 74 mmol

Now, we put this value into equation (1) as follows.

$\frac{74 - x}{74 + x} = 0.1$

x = 60.5

This means that moles of acid added is 60.5 mmol.

As it is given that molarity is 0.180 M. Therefore, calculate the volume of acid as follows.

Volume of acid = $\frac{moles}{molarity}$

= $\frac{60.5 mmol}{0.180 M}$

= 336.1 ml

Thus, we can conclude that the maximum volume of 0.180 M HCl that can be added to the buffer before its buffering capacity is lost is 336.1 ml.

Answer from: Quest

False because saturated fatty acids contain only single bond

Answer from: Quest

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. $hbr$ completely dissociates to $h^+$ and $br-$ ions. a is incorrect because $h_2s$ does not fully ionize to $h^+$ and $hs^-$ ions and some remain as the compound $h_2s$ . c and d are incorrect because, $li_2o$ and $libr$ do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise, if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both $li_2o$ and $libr$ have a complete octet so can not accept any electrons which disqualifies them as acids.

Another question on Chemistry

Chemistry, 21.06.2019 20:30

10. translate each of the following chemical equations into a sentence. a. 2 zns(s) + 3 o2(g) -> 2 zno(s) + 2 so2(g) b. cah2(s) + 2 h2o(l) -> ca(oh)2 (aq) + 2 h2(g)

Answers: 2

Answer

Chemistry, 22.06.2019 09:00

George is a dalmatian puppy. describe what happens to light that allows you to see george’s black and white coat.

Answers: 1

Answer

Chemistry, 22.06.2019 12:00

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Answers: 2

Answer

Chemistry, 22.06.2019 19:30

Awoman's basketball has a circumference between 28.5 and 29.0 inches and a maximum weight of 20 ounces (two significant figures). what are these specifications in units of centimeters and grams?

Answers: 2

Answer

You know the right answer?

Buffer capacity is a measure of a buffer solution's resistance to changes in ph as strong acid or ba...

Questions