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
lawyer [7]
3 years ago
8

The side chain of tyrosine has a pKa of about 10. What percent of tyrosine side chains would be deprotonated at pH 8.5?

Chemistry
1 answer:
bezimeni [28]3 years ago
3 0

Answer:

Explanation:

Let the tyrosine molecule be represented by TH . It will ionise in water as follows

TH ⇄ T⁻ + H⁺

Let C be the concentration of undissociated TH and α be the degree of dissociation

TH       ⇄       T⁻ + H⁺

c                    0       0   ( before )

c( 1-α )            αc      αc ( after ionisation)

Ka = α²c² / c( 1-α )

= α²c  ( neglect α in the denominator as it is very small )

pKa = 10

Ka  = 10⁻¹⁰

pH = 8.5

H⁺ = 10⁻⁸°⁵

αc = 10⁻⁸°⁵

α²c =Ka = 10⁻¹⁰

α x10⁻⁸°⁵ = 10⁻¹⁰

α = 10⁻¹⁰⁺⁸°⁵

= 10⁻¹°⁵ = 1 / 31.62

Percentage of dissociation = 100 / 31.62

= 3.16 %

percent of  tyrosine side chains   deprotonated

You might be interested in
Would anyone be able to give a good explanation of what
mezya [45]

Answer and Explanation:

Aspirin is odorless, but when left exposed to air in the environment, it gradually hydrolyzes into salicylic acid and acetic acid as that is the precursor for synthesizing Aspirin.

Using this hydrolyzed aspirin for titration would not be advised, because it would affect the reading of the titration. Ordinarily, apsirin is a weak acid and direct titration of aspirin is problematic because it hydrolyzes pretty fast to salicylic acid— leading to an unwanted side reaction which may or may not go to completion. Therefore, excess base must be added and heat is supplied to the mixture so that neutralization and hydrolysis are complete. The remaining base is then titrated. This is called back titration.

Now, in back titration, instead of using solution whose concentration is expected to be known, we rather use excess volume of reactant which has been left over after the completion of a reaction with the analyte.

In this case, we use an alkali, preferably NaOH (1.0 mol/dm³). Te unused NaOH remaining after the hydrolysis is titrated against a standard HCl (0.1 mol/dm³). Then from the reaction equation of the aspirin and sodium hydroxide, the amount of NaOH required for the hydrolysis can be calculated.

Answering whether the titration goes up or down, it would be observed that the titration reading would GO DOWN because the exposed aspirin used has experienced some form of hydrolysis before it was used for titration, so the hydrolysis reaction it would undergo with acetyl-salicylic acid would be minimal, and this would affect the titration reading.

But if the aspirin wasn't left exposed to the environment, the reading would go up since more hydrolysis would take place in this case.

3 0
3 years ago
Which equation is used to find the density of a solid?
Romashka-Z-Leto [24]
Mass + Volume = Density
7 0
2 years ago
Answer the question below 100 points and brainlist
Kipish [7]

Answer:

i think A but im not sure

Explanation:

5 0
2 years ago
Read 2 more answers
To separate liquids in a mixture of different liquids, each having different boiling points, one would use the separation techni
sleet_krkn [62]

Answer;

-Distillation

Explanation;

Distillation is a  technique that can be used to physically separate most homogeneous mixtures based on the difference in the boiling points of the substances involved.

A good example;  A flask hold liquids A, B, and C in a homogeneous mixture. The boiling points of A, B, and C are 130 C, 65 C, and 71 C, respectively. The flask is heated to 65C until all of liquid B is filtered out. The remaining mixture is heated to 71C until all of liquid C is filtered out, and only liquid A is left in the flask.

7 0
2 years ago
How many moles are in 1.4 x 10^21 atoms of sodium?
Zepler [3.9K]

Answer:

devide by avogadro constant 6.02*10^23

Explanation:

3 0
2 years ago
Other questions:
  • Classify equation<br> Write the correct chemical formula<br> Balance equation
    8·1 answer
  • Nyatakan tiga bentuk bagi atom karbon dan perbezaan ringkas diantara ketiga-tiga atom karbon tersebut
    12·1 answer
  • _____ can be defined as the rate at which velocity changes
    12·2 answers
  • Which type of chemical reaction occurs in C6H12 + 9O2 ----- 6CO2 + 6H2O?
    9·1 answer
  • A student constructs an electrochemical cell. A diagram of the operating cell and the unbalanced ionic equation representing the
    12·1 answer
  • What is the best definition of energy?
    13·2 answers
  • The C2-C3 single bond in butane freely rotates at room temperature, see equation (1) below. In contrast, the C2-C3 single bond i
    13·1 answer
  • Liquid A is known to have a lower surface tension and lower viscosity than Liquid B. Use these facts to predict the result of be
    6·1 answer
  • How many neutrons in an atom of 30p? O a. 17 O b. 30.974 O c. 15 O d. 14 O e. 16
    7·1 answer
  • 8. Consider the element Scandium, atomic # 21.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!