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Aleksandr-060686 [28]
3 years ago
12

A student is comparing two samples of crystalline organic solids. A TLC analysis shows a single spot for each sample and the co-

spot with the same Rf value. Which of the following would provide the most conclusive evidence that the two samples are the same compound?
-rerun the TLC using more developing solvent
-rerun the TLC on a longer TLC plate
-Perform a mixture melting point
-mix the substances and run the TLC as a single spot
Chemistry
1 answer:
Digiron [165]3 years ago
5 0

Answer:

Rerun the TLC using more developing solvent

Explanation:

The TLC principle envolves the interaction of the samples with the solvent and the stationary phase.

For the solvent you are using at the moment, the interaction with the sample may be very similar for both cases depending with the polarity, what could indicate an equal value.

If you develops a new solvent with a different polarity, you can see if the samples are the same compound or not. Because a more polar compound will interact more with the stationary phase and a more non-polar compound will interact more with the solvent.

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bagirrra123 [75]
This may help you

Allright for <span><span>H2</span>O:</span> - The central atom is? --> the oxygen atom - How many atoms are bonded to the central atom? --> 2 hydrogen atoms - How many lone pairs of electrons are on the central atom? --> O has 6 electrons and has 2 single bonds, so 2 pairs - How many single bonds are there in this molecule? --> 2 - How many multiple bonds (double and/or triple) are there in this molecule? --> none For each of your molecules, answer the following questions: 1. Determine the electronegativity between the atoms of each molecule. Electronegativity O = 3.44 Electronegativity H = 2.20 3.44-2.20=1.24, so the electronegativity between O and H = 1.24 2. Identify the bond as either ionic or covalent. Electronegativity of 0.0-1.7 = covalent Electronegativity of 1.7-3.3 = ionic So it's a covalent bond 3. State whether the molecule is polar or non polar. Electronegativity of 0.5-1.7= polar covalent 4. Identify the structure as having hydrogen bonding, dipole-dipole moments or London dispersion forces (LDF). <span><span>H2</span>O</span><span> = hydrogen bonding</span>
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3 years ago
State whether each of the following would increase, decrease, or leave the initial pH unchanged and explain your reasoning: Usin
fgiga [73]

Answer:

1. Decrease the pH

2. The pH remains unchanged

3. Decrease the pH

Explanation:

We can calculate the pH of a weak acid using the following expression:

pH=-log [H^{+} ]=-log\sqrt{Ka \times Ca }   [1]

where,

Ka is the acid dissociation constant

Ca is the initial concentration of the acid

<em>State whether each of the following would increase, decrease, or leave the initial pH unchanged and explain your reasoning</em>

  1. <em>Using the same weak acid, but having a higher concentration. </em>According to eq. [1], a higher Ca leads to a higher [H⁺] and a lower pH.
  2. <em>Using 80.00 mL of this weak acid instead of 40.00 mL.</em> pH refers to a concentration, which is an intensive property, so it does not change when we change the amount of matter.
  3. <em>Using a different weak acid that has a larger Ka value.</em> According to eq. [1], a higher Ka leads to a higher [H⁺] and a lower pH.
5 0
3 years ago
A child has blue eyes whereas his mother has brown eyes. Which of the following explains why the child has blue eyes? Some diet
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Answer:

A piece of DNA from the father carried the trait for blue eye color

4 0
3 years ago
Read 2 more answers
Discussion: (24 points)
lorasvet [3.4K]
What exactly is this asking
6 0
3 years ago
Sharing of electrons between two bonded atoms always indicates
Oliga [24]
A covalent bond. :-)
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