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dedylja [7]
2 years ago
9

What would happen if a TLC plate was placed in a jar where the solvent level was above the level of the origin (sample spot)? Wh

at should you do if you inadvertently spotted your plate too low (aside from consulting your TA)?
Chemistry
2 answers:
Hitman42 [59]2 years ago
8 0

Answer:

Thin layer chromatography (TLC) is a form of qualitative analysis called adsorption

chromatography used almost daily in synthetic organic chemistry labs. The composition of a

mixture can be assessed relative to known standards and separation of the mixture is roughly

based on polarity. In brief, a small portion of the sample is placed on the stationary phase

(polar silica) and is carried up the TLC plate by the mobile phase (solvent). A polar compound

will interact more with the polar stationary phase and will not travel as far up the plate.

Conversely, a less polar compound will move farther up the plate. Notice that this technique is

not terribly different from GC. Separation is based on polarity in both cases – relative boiling

points can be estimated from polarity. Mobile and stationary phases are still employed, except

that the states of matter are different. The principles of TLC will later be applied to column

chromatography, where larger sample volumes will be physically separated and isolated based

on polarity of the components. In this lab, students will use solvents of different polarity (mobile

phases) to determine the optimal separation of the pigments found in spinach extracts.

The most prominent types of plant pigments are chlorophylls, carotenoids, flavanoids,

and tannins. Chlorophylls contain a ring system formed by four pyrroles linked by four methine

bridges, a Mg2+ ion in its center, and a long nonpolar hydrocarbon chain (C20H39). Chlorophylls are

cousins of other biologically important molecules such as vitamin B12 and the heme found in

hemoglobin; they all have a tetrapyrrole ring system. There are two main types of chlorophylls

present in higher plants, a and b. Chlorophyll a is more abundant than chlorophyll b by a ratio of 3

to 1. The only structural difference between them is that a methyl group in a has been replaced by

a formyl group, CHO, in b.

Explanation:

nika2105 [10]2 years ago
7 0

Answer: ok

Explanation:

You might be interested in
Please help! Thanks :D
Digiron [165]
<h3>1</h3>

Species shown in bold are precipitates.

  • Ca(NO₃)₂ + 2 KOH → Ca(OH)₂ + 2 KNO₃
  • Ca(NO₃)₂ + Na₂C₂O₄ → CaC₂O₄ + 2 NaNO₃
  • Cu(NO₃)₂ + 2 KI → CuI₂ + 2 KI
  • Cu(NO₃)₂ + 2 KOH → Cu(OH)₂ + 2 KNO₃
  • Cu(NO₃)₂ + Na₂C₂O₄ → CuC₂O₄ + 2 NaNO₃
  • Ni(NO₃)₂ + 2 KOH → Ni(OH)₂ + 2 KNO₃
  • Ni(NO₃)₂ + Na₂C₂O₄ → NiC₂O₄ + 2 NaNO₃
  • Zn(NO₃)₂ + 2 KOH → Zn(OH)₂ + 2 KNO₃
  • Zn(NO₃)₂ + Na₂C₂O₄ → ZnC₂O₄ + 2 NaNO₃

<h3>2</h3>

A double replacement reaction takes place only if it reduces in the concentration of ions in the solution. For example, the reaction between Ca(NO₃)₂ and KOH produces Ca(OH)₂. Ca(OH)₂ barely dissolves. The reaction has removed Ca²⁺ and OH⁻ ions from the solution.

Some of the reactions lead to neither precipitates nor gases. They will not take place since they are not energetically favored.


<h3>3</h3>

Compare the first and last row:

Both Ca(NO₃)₂ and Zn(NO₃)₂ react with KOH. However, between the two precipitates formed, Ca(OH)₂ is more soluble than Zn(OH)₂.

As a result, add the same amount of KOH to two Ca(NO₃)₂ and Zn(NO₃)₂ of equal concentration. The solution that end up with more precipitate shall belong to Zn(NO₃)₂.


<h3>4</h3>

Compare the second and third row:

Cu(NO₃)₂ reacts with KI, but Ni(NO₃)₂ does not. Thus, add equal amount of KI to the two unknowns. The solution that forms precipitate shall belong to Cu(NO₃)₂.

8 0
3 years ago
The substances that are produced after the chemical reaction are called the ___​
sertanlavr [38]

Answer:

Products

Explanation:

During a chemical reaction, there are the reactants (left side), and the products (right side).

6 0
2 years ago
Read 2 more answers
G(1)=0 g(n) =g(n-1)+n g(2)=
Aliun [14]
G(2)=2

For this, you can plug in 2 everywhere you see an n. So the equation will read:
g(2)=g(2-1)+2 -> g(2)=g(1)+2. Since we are given g(1)=0, we can plug in 0 where we see g(1). The equation is now. g(2)=0+2. So, g(2)=2.
6 0
3 years ago
(2-2) Looking at the chemical formula CaF2 (calcium fluoride), what do you think this substance is made of? (Choose ALL that app
mixer [17]

Answer:

Metal

Non-metal

Explanation:

CaF2 is an ionic compound. Ionic compounds are mostly composed of a metal and a non metal. Metals donate electrons to non-metals to form ionic compounds.

Calcium is a divalent ion of group two in the periodic table while F is a univalent nonmetal of group 17 in the periodic table. Hence the compound CaF2 is composed of a metal and a nonmetal.

7 0
3 years ago
An individual has calculated her ecological footprint. What does this
Lunna [17]

Answer: C

Explanation:

The impact she has on the environment

6 0
3 years ago
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