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 The only structural difference between them is that a methyl group in a has been replaced by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

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I'm looking at the barometer in my lab as I type this question. It says the pressure is 968 torr. What is this pressure expresse
Ksenya-84 [330]

Answer:

1.27 atm.

Explanation:

The following data were obtained from the question:

Pressure (P) in torr = 968 torr

Pressure (P) in atm =...?

Thus, we can convert from torr to atm by doing the following:

Recall:

760 torr = 1 atm

Therefore,

968 torr = 968/760 = 1.27 atm

Therefore, 968 torr is equivalent to 1.27 atm.

7 0
3 years ago
How many joules of energy are made by the loss of 100kg of mass using the formula E=mc2? please help!!!
asambeis [7]

Answer:

E = 3 × 10¹⁰ J

Explanation:

Mass, m = 100 kg

We need to find energy made by the loss of 100 kg of mass. The formula between the mass and energy is given by :

E = mc²

Where c is speed of light

Putting all the values, we get :

E = 100 kg × (3×10⁸ m/s)²

= 3 × 10¹⁰ J

So, the required energy is 3 × 10¹⁰ J.

6 0
3 years ago
The compound sodium thiosulfate pentahydrate, Na2S2O3 • 5H2O
Mnenie [13.5K]

The theoretical yield is 204.4 g while the percent yield is 2.57%.

<h3>What is theoretical yield?</h3>

Theoretical yield is the amount of product obtained based on the stoichiometry of the reaction.

S8(s) + 8 Na2SO3(aq) + 40 H2O(l) --->8 Na2S2O3·5 H2O(s)

Number of moles of sulfur =  3.25 g /8(32) = 0.013 moles

Number of moles of sodium sulfite =  13.1 g/126 g/mol = 0.103 moles

Since 1 moles of sulfur reacts with 8 moles of sodium sulfite

0.013 moles reacts with 0.013 moles ×  8 moles /1 mole = 0.104 moles

There is not enough sodium sulfite hence it is the limiting reactant.

1 mole of sodium sulfite yields 8 moles of product

0.103 moles of sodium sulfite yields  0.103 moles × 8 moles /1 mole = 0.824 moles

Mass of product = 0.824 moles × 248 g/mol = 204.4 g

percent yield =  5.26 g /204.4 g × 100/1

= 2.57%

Learn more about percent yield: brainly.com/question/2506978

4 0
2 years ago
What identifies an ion
bezimeni [28]

Answer:

Identifying whether or not an element is an ion is a very simple process. Identify the charge of the element. ... The number of electrons is equal to the atomic number minus the charge of the atom. Refer to an element with either a positive or negative charge as an ion.

7 0
3 years ago
What is cement and who invented it?
Sonja [21]

Answer:

Cement is a combination of calcium, silicone, aluminum, iron and lots of other ingredients to make side walks, home made crafts, etc. The person who invented concrete is Joseph Aspdin.

Explanation:

5 0
3 years ago
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