1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
natta225 [31]
1 year ago
14

Calculate the pKa of lactic acid (CH3CH(OH)COOH) given the following information. 3.005 grams of potassium lactate are added to

100. mL of a 0.500 M lactic acid solution producing a pH of 3.526.
Chemistry
1 answer:
snow_lady [41]1 year ago
5 0

Answer:

\displaystyle \text{p} K_a \approx 3.856

Explanation:

Because 3.005 grams of potassium lactate is added to 100. mL of solution, its concentration is:


\displaystyle \begin{aligned} \left[ \text{KC$_3$H_$_5$O$_3$}\right]  & = \frac{3.005\text{ g KC$_3$H_$_5$O$_3$}}{100.\text{ mL}} \cdot \frac{1\text{ mol KC$_3$H_$_5$O$_3$}}{128.17 \text{ g KC$_3$H_$_5$O$_3$}} \cdot \frac{1000\text{ mL}}{1\text{ L}} \\ \\ &= 0.234\text{ M}\end{aligned}

By solubility rules, potassium is completely soluble, so the compound will dissociate completely into potassium and lactate ions. Therefore, [KC₃H₅O₃] = [C₃H₅O₃⁺]. Note that lactate is the conjugate base of lactic acid.

Recall the Henderson-Hasselbalch equation:

\displaystyle \begin{aligned}\text{pH} = \text{p}K_a + \log \frac{\left[\text{Base}\right]}{\left[\text{Acid}\right]} \end{aligned}

[Base] = 0.234 M and [Acid] = 0.500 M. We are given that the resulting pH is 3.526. Substitute and solve for p<em>Kₐ</em>:

\displaystyle \begin{aligned} (3.526) & = \text{p}K_a + \log \frac{(0.234)}{(0.500)} \\ \\ 3.526 & = \text{p}K_a + (-0.330) \\ \\ \text{p}K_a & = 3.856\end{aligned}

In conclusion, the p<em>Kₐ </em>value of lactic acid is about 3.856.

You might be interested in
Which type of covalent bond is the least stable?
sergejj [24]

Hello ^^

Answer:

D.Triple Bonds

Explanation:

A Triple bond is when three pairs of electrons are shared between two atoms in a molecule. It is the least stable out of the three general types of covalent bonds.

Hope this helps!

Have an awesome day!

If you have any questions please ask.

8 0
2 years ago
Read 2 more answers
Wat are the five assumption of kinetic therory of gases​
il63 [147K]

Answer:

The five assumption of Kinetic molecular theory are given below.

Explanation:

Kinetic molecular theory of gasses stated that,

1) Gases consist of large number of smaller particles which are distance apart from each others.

2) The gas molecules collide with each other and also with wall of container and this collision is elastic.

3) Gas molecules are in continuous random motion and posses kinetic energy.

4) The forces of attraction between gas molecules are very small and considered negligible.

5) The temperature of gas is directly proportional to average kinetic energy of gas molecules.

6 0
3 years ago
Balance this chemical equation with an explanation please: CH3CH2OH + O2 = CO2 + H2O
STALIN [3.7K]
CH3CH2OH + 3O2 = 2CO2 + 3H2O

Basically you do trial and error on both sides so they can be equal
3 0
3 years ago
2 UNIS<br> Which of the following interactions is not a type of intermolecular force?
natima [27]

Answer:

Covalent Bonds

Explanation:

7 0
3 years ago
A sample of argon gas has a volume of 698.7l. The temp is decreased to 24.8c and the volume also decreases to 499.1l. What was t
Rina8888 [55]
ASsfh 977. Hoon mein
4 0
2 years ago
Other questions:
  • Explain how will you know the mass of the water in your experiment?
    9·1 answer
  • The nuclear fission process releases neutrons and
    5·1 answer
  • Define not matter and give examples​
    15·1 answer
  • What is the name of this hydrocarbon?
    8·2 answers
  • Convert ethene to propanol​
    12·1 answer
  • Climate has changed naturally throughout Earth’s history, but how is climate change today different?
    11·1 answer
  • How many moles of magnesium oxide are formed if you burn a 2.3 mol sample of magnesium ribbon in the air? You must show ALL work
    8·1 answer
  • What is chyme? It’s a brain-pop question
    5·2 answers
  • A habit is: <br>pls help me ty​
    13·2 answers
  • Water is a polar molecule. That means it has
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!