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4 years ago

Which is the basis of thin-layer chromatography?

Chemistry

1 answer:

solmaris [256]4 years ago

8 0

Answer:

B.) The drug gets carried through a stationary phase by a mobile phase and the retention time identifies the drug.

Explanation:

Chromatography is used in purifying complex mixtures of organic compounds. It uses the adsorption tendencies of compounds to seperate and identify them.

Chromatography is made up of two phases in contact, the stationary phase or non-mobile phase and the mobile phase. The movement of the mobile phase over the stationary phase causes the separation of a mixture into its constituents.

The stationary phase is made up of silica-gel or alumina in a solvent (an adsorbent) and the mobile phase or carrier is the organic solvent which is the drug.

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An average reaction rate is calculated as the change in the concentration of reactants or products over a period of time in the

Sauron [17]

Answer:

a) 0.000112 M/s is the average reaction rate between 0.0 seconds and 1500.0 seconds.

b) 0.00011 M/s is the average reaction rate between 200.0 seconds and 1200.0 seconds.

c) Instantaneous rate of the reaction at t=800 s :

Instantaneous rate : $\frac{0.031 M}{800.0 s}=3.875\times 10^{-5} M/s$

Explanation:

Average rate of the reaction is given as;

$R_{avg}=-\frac{\Delta A}{\Delta t}=\frac{A_2-A_1}{t_2-t_1}$

a.) The average reaction rate between 0.0 s and 1500.0 s:

At 0.0 seconds the concentration was = $A_1=0.184 M$

$t_1=0.0s$

At 1500.0 seconds the concentration was = $A_2=0.016 M$

$t_2=1500 s$

$R_{avg]=-\frac{0.016 M-0.184 M}{1500.0 s-0.0 s}=0.000112 M/s$

0.000112 M/s is the average reaction rate between 0.0 seconds and 1500.0 seconds.

b.) The average reaction rate between 200.0 s and 1200.0 s:

At 0.0 seconds the concentration was = $A_1=0.129 M$

$t_1 =200.0 s$

At 1500.0 seconds the concentration was = $A_2=0.019M$

$t_2=1200 s$

$R_{avg]=-\frac{0.019 M-0.129M}{1200.0s-200.0s}=0.00011 M/s$

0.00011 M/s is the average reaction rate between 200.0 seconds and 1200.0 seconds.

c.) Instantaneous rate of the reaction at t=800 s :

At 800 seconds the concentration was = $A=0.031 M$

$t =800.0 s$

Instantaneous rate : $\frac{0.031 M}{800.0 s}=3.875\times 10^{-5} M/s$

8 0

4 years ago

Hi, this is for chemistry. If anyone could answer this that would be great:) thank you!

otez555 [7]

answer 4 I checked online it's correct

3 0

3 years ago

Write the chemical symbols for three different atoms or atomic cations with 18 electrons.

Ugo [173]

<span>Chlorine has 17 electrons in it natural state but it gains an electron and becomes an anion with 18 electrons. </span>

Potassium (K) has 19 electrons in its natural state. It loses an electron and becomes K+ and then is left with 18 <span>electrons .
</span>
The atomic number of calcium is 20 i.e. Ca has 20 electrons.It Loses 2 electrons and becomes Ca++ and has 18 electrons.

7 0

4 years ago

Why does the magnitude and direction of the inertial force on the body is always zero for a freely falling body

svlad2 [7]

Answer:

Because his first law states that an object with a net force of zero acting on it will remain at rest, if initially at rest, or it will maintain a constant velocity.

5 0

3 years ago

Which of the following naturally orccuing radioisotopes would be most useful in dating objects

Sergeu [11.5K]

Potassium -40half life = 1.28 ×10∧9.
Radioisotope can be used to determine the age of fossils, to treat skin disease, to sterilize foodstuffs, and also to sterilize surgical instruments.
Radioisotope dating is a way to estimate a fossil's age by a method of analyzing the elemental isotopes which are within the rocks which it is in.

3 0

3 years ago