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
Salsk061 [2.6K]
3 years ago
15

What information does the chemical shift of an nmr signal convey? select the correct answer?

Chemistry
2 answers:
alexdok [17]3 years ago
8 0
The answer to your question is position and number of chemical shifts give information about the structure of a organic molecule. Chemical shift describes the relative positions of the resonances in an NMR spectrum. It is also the position on the δ scale (ppm - parts per million) where the peak occurs.
mixas84 [53]3 years ago
4 0
Answer is: <span>position and number of </span>chemical shifts give information about the structure of a organic molecule. Chemical shift<span> is the position on the δ scale (ppm - parts per million) where the peak occurs. </span>Chemical shift<span> describe the relative positions of the resonances in an NMR spectrum.</span>
You might be interested in
Which of the following mixtures may be act as a buffer solution?
lions [1.4K]

Answer:

B) HF, NaF

Explanation:

  • A buffer solution is made up of a weak acid and its conjugate base.
  • In this case, HF is a weak acid and NaF is the conjugate base, therefore the mixture of HF,  and NaF would make a perfect buffer solution.
  • The buffer would have the weak acid HF and its conjugate base, F- which comes from the soluble salt NaF.
4 0
3 years ago
Which of the following equations does not demonstrate the law of conservation of mass
tia_tia [17]
The answer is c :) i hope its the right answer
8 0
3 years ago
Read 2 more answers
A 20.0 mL 0.100 M solution of lactic acid is titrated with 0.100 M NaOH.
yan [13]

Answer:

(a) See explanation below

(b) 0.002 mol

(c) (i) pH = 2.4

(ii) pH = 3.4

(iii) pH = 3.9

(iv) pH = 8.3

(v) pH = 12.0

Explanation:

(a) A buffer solution exits after addition of 5 mL of NaOH  since after reaction we will have  both the conjugate base lactate anion and unreacted weak  lactic acid present in solution.

Lets call lactic acid HA, and A⁻ the lactate conjugate base. The reaction is:

HA + NaOH ⇒ A⁻ + H₂O

Some unreacted HA will remain in solution, and since HA is a weak acid , we will have the followin equilibrium:

HA  + H₂O ⇆ H₃O⁺ + A⁻

Since we are going to have unreacted acid, and some conjugate base, the buffer has the capacity of maintaining the pH in a narrow range if we add acid or base within certain limits.

An added acid will be consumed by the conjugate base A⁻ , thus keeping the pH more or less equal:

A⁻ + H⁺ ⇄ HA

On the contrary, if we add extra base it will be consumed by the unreacted lactic acid, again maintaining the pH more or less constant.

H₃O⁺ + B ⇆ BH⁺

b) Again letting HA stand for lactic acid:

mol HA =  (20.0 mL x  1 L/1000 mL) x 0.100 mol/L = 0.002 mol

c)

i) After 0.00 mL of NaOH have been added

In this case we just have to determine the pH of a weak acid, and we know for a monopric acid:

pH = - log [H₃O⁺] where  [H₃O⁺] = √( Ka [HA])

Ka for lactic acid = 1.4 x 10⁻⁴  ( from reference tables)

[H₃O⁺] = √( Ka [HA]) = √(1.4 x 10⁻⁴ x 0.100) = 3.7 x 10⁻³

pH = - log(3.7 x 10⁻³) = 2.4

ii) After 5.00 mL of NaOH have been added ( 5x 10⁻³ L x 0.1 = 0.005 mol NaOH)

Now we have a buffer solution and must use the Henderson-Hasselbach equation.

                            HA          +         NaOH          ⇒   A⁻ + H₂O

before rxn         0.002                  0.0005                0

after rxn    0.002-0.0005                  0                  0.0005

                        0.0015

Using Henderson-Hasselbach equation :

pH = pKa + log [A⁻]/[HA]

pKa HA = -log (1.4 x 10⁻⁴) = 3.85

pH = 3.85 + log(0.0005/0.0015)

pH = 3.4

iii) After 10.0 mL of NaOH have been ( 0.010 L x 0.1 mol/L = 0.001 mol)

                             HA          +         NaOH          ⇒   A⁻ + H₂O

before rxn         0.002                  0.001               0

after rxn        0.002-0.001                  0                  0.001

                        0.001

pH = 3.85 + log(0.001/0.001)  = 3.85

iv) After 20.0 mL of NaOH have been added ( 0.002 mol )

                            HA          +         NaOH          ⇒   A⁻ + H₂O

before rxn         0.002                  0.002                 0

after rxn                 0                         0                   0.002

We are at the neutralization point and  we do not have a buffer anymore, instead we just have  a weak base A⁻ to which we can determine its pOH as follows:

pOH = √Kb x [A⁻]

We need to determine the concentration of the weak base which is the mol per volume in liters.

At this stage of the titration we added 20 mL of lactic acid and 20 mL of NaOH, hence the volume of solution is 40 mL (0.04 L).

The molarity of A⁻ is then

[A⁻] = 0.002 mol / 0.04 L = 0.05 M

Kb is equal to

Ka x Kb = Kw ⇒ Kb = 10⁻¹⁴/ 1.4 x 10⁻⁴ = 7.1 x 10⁻¹¹

pOH is then:

[OH⁻] = √Kb x [A⁻]  = √( 7.1 x 10⁻¹¹ x 0.05) = 1.88 x 10⁻⁶

pOH = - log (  1.88 x 10⁻⁶ ) = 5.7

pH = 14 - pOH = 14 - 5.7 = 8.3

v) After 25.0 mL of NaOH have been added (

                            HA          +         NaOH          ⇒   A⁻ + H₂O

before rxn           0.002                  0.0025              0

after rxn                0                         0.0005              0.0005

Now here what we have is  the strong base sodium hydroxide and A⁻ but the strong base NaOH will predominate and drive the pH over the weak base A⁻.

So we treat this part as the determination of the pH of a strong base.

V= (20 mL + 25 mL) x 1 L /1000 mL = 0.045 L

[OH⁻] = 0.0005 mol / 0.045 L = 0.011 M

pOH = - log (0.011) = 2

pH = 14 - 1.95 = 12

7 0
2 years ago
Please help like please
klemol [59]

Answer:

It is the third one

Explanation:

"Both atoms achieve a more stable configuration."

4 0
2 years ago
Read 2 more answers
In which are the ionic solids ranked in order of increasing melting point?
abruzzese [7]

Answer:A

Explanation:

The melting points of solids depend in the relative sizes of ions in the ionic lattice. The smaller the relative sizes of the ions, the higher the lattice energy and the stronger the lattice hence higher melting point. Comparing relative ionic sizes, fluoride ion is lesser in size than chloride ion hence NaF has a higher melting point than NaCl.

7 0
3 years ago
Other questions:
  • How do you do this problem?
    7·1 answer
  • 1<br> What is the sum of all the protons and neutrons in an atom?
    11·1 answer
  • How do knowing the half-life of carbon 14 can tell scientists the absolute age of a rock sample
    5·1 answer
  • Draw the major organic substitution product(s) for (2R,3S)-2-bromo-3-methylpentane reacting with the given nucleophile. Indicate
    12·1 answer
  • ASAP!!!! ILL GIVE BRAINIEST
    14·2 answers
  • 24. Which description correctly identifies the substance below?*
    14·1 answer
  • An experiment shows that 113 mL gas sample at pressure of 721mmHg changed to 901 mmHg.
    8·1 answer
  • "Show a general equation for polymerisation"
    6·1 answer
  • When magnesium hydroxide reacts with nitric acid, it produces magnesium nitrate and water
    11·1 answer
  • Is this chemical equation balanced?<br> Yes or no
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!