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Tema [17]
3 years ago
14

A TLC plate showed 2 spots with Rf values of 0.25 and 0.26. The plate was removed from the developing chamber, the residual solv

ent was allowed to evaporate from the plate, and then the plate was returned to the developing chamber. What would you expect to see after the second development was complete
Chemistry
1 answer:
Katena32 [7]3 years ago
4 0

Answer:

See explanation

Explanation:

TLC is a chromatographic method in which the solute is spotted on a plate and the plate is placed in an air tight chamber containing a solvent. The solvent is maintained below the level of the spot. The capillary movement of the solvent through the plate achieves the required separation.

If two spots have Rf values of 0.25 and 0.26 respectively and then the plate was removed from the developing chamber, subsequently, the residual solvent was allowed to evaporate from the plate, and then the plate was returned to the developing chamber.

It will be observed after the second development is complete that the new Rf values will be 0.50 and 0.52 respectively. It will just be as though the second chromatogram picked up from where the first chromatogram stopped.

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3 years ago
In a mixture of hydrogen and nitrogen gases, the mole fraction of nitrogen is 0.333. If the partial pressure of hydrogen in the
notka56 [123]

Answer:

P_T=112.4torr

Explanation:

Hello there!

In this case, since these problems about gas mixtures are based off Dalton's law in terms of mole fraction, partial pressure and total pressure, we can write the following for hydrogen, we are given its partial pressure:

P_{H_2}=x_{H_2}*P_T

And can be solved for the total pressure as follows:

P_T=\frac{P_{H_2}}{x_{H_2}}

However, we first calculate the mole fraction of hydrogen by subtracting that of nitrogen to 1 due to:

x_{H_2}+x_{N_2}=1\\\\x_{H_2}=1-0.333=0.667

Then, we can plug in to obtain the total pressure:

P_T=\frac{75.0torr}{0.667}\\\\P_T=112.4torr

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3 years ago
Which of the following statements does not describe what he structure of an atom an atom has a small dense center called nucleus
nikklg [1K]

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5 0
3 years ago
A 0.75M solution of CH3OH is prepared in 0.500 kg of water. How many moles of CH3OH are needed?
4vir4ik [10]

Answer:

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Explanation:

For the problem they give us the following data:

Solution concentration 0,75 M

Mass of Solvent is 0,5Kg

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                           d = \frac{g}{mL} \\\\ V= \frac{g}{d}  = \frac{500g}{1 \frac{g}{mL} } = 500mL = 0,5 L

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therefore the solution is prepared using 0.5 L of H2O and 0.375 moles of CH3OH,  resulting in a concentration of 0,75M

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3 years ago
How can you tell which ionic compounds will react in an aqueous solution
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1.  Determine if the ionic substances can break apart into ions.
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3 0
3 years ago
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