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the reaction A->B is second order in A and the rate constant is 0.039L/mol s. if it took 23 sec for the concentration of A to decrease to 0.30 M, what was the starting concentration of A

Answers

Answer 1

Answer:

Answer:

0.41 M

Explanation:

A -> B

rate constant (k) = 0.039L/mol s

t = 23

Final concentration, [A] = 0.30M

Initial concentration, [A]o = x

1 / [A] = kt + 1 / [A]o

1 / [A]o = 1 / [A] - kt

1 / [A]o = 1 / 0.30 - 0.039 (23)

1 / [A] = 3.33 - 0.897 = 2.433

[A] = 0.41 M

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Why is it impossible to perform a liquid-liquid extraction using h2o (water)and ch3oh (methanol)?

Answers

Solution : Water and Methanol are easily miscible in any amount. so they are not preferred for the liquid-liquid extraction process.

Liquid-Liquid Extraction is also called as solvent extraction. It is the method of seperation of compound based on their relative solubilities in two different immiscible liquids. Generally we use water (polar) and an organic solvent (non-polar).

It is important that the two solvents should not be mix because it is easy to seperate them.

Water and Methanol are easily miscible in any amount. we can not seperate them easily. So that is why we can not use water and methanol as a solvent in liquid-liquid extraction process.

Answer:

they could be joined due to hydrogen bridge-type intermolecular interactions so no phase splitting will be carried out.

Explanation:

Hello,

Liquid-liquid extraction is a widely used separation operation that is suitable when relative volatilities are so close, so an extra substance is used to modify the equilibrium causing a phase splitting (two liquid immiscible phases) which could be leveraged to mechanically separate the two phases. The basic idea lies on the fact that the extra substance must be largely immiscible with the original solvent, to the solute is selectively separated, nonetheless, in this case, water and methanol are largely soluble to each other since they could be joined due to hydrogen bridge-type intermolecular interactions so no phase splitting will be carried out.

Best regards.

A chemist titrates 160.0mL of a 0.3403M aniline C6H5NH2 solution with 0.0501M HNO3 solution at 25°C . Calculate the pH at equivalence. The pKb of aniline is 4.87 . Round your answer to 2 decimal places. Note for advanced students: you may assume the total volume of the solution equals the initial volume plus the volume of HNO3 solution added.

Answers

Answer : The pH of the solution is, 5.24

Explanation :

First we have to calculate the volume of $HNO_3$

Formula used :

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the initial molarity and volume of $C_6H_5NH_2$ .

$M_2\text{ and }V_2$ are the final molarity and volume of $HNO_3$ .

We are given:

$M_1=0.3403M\nV_1=160.0mL\nM_2=0.0501M\nV_2=?$

Putting values in above equation, we get:

$0.3403M* 160.0mL=0.0501M* V_2\n\nV_2=1086.79mL$

Now we have to calculate the total volume of solution.

Total volume of solution = Volume of $C_6H_5NH_2$ + Volume of $HNO_3$

Total volume of solution = 160.0 mL + 1086.79 mL

Total volume of solution = 1246.79 mL

Now we have to calculate the Concentration of salt.

$\text{Concentration of salt}=(0.3403M)/(1246.79mL)* 160.0mL=0.0437M$

Now we have to calculate the pH of the solution.

At equivalence point,

$pOH=(1)/(2)[pK_w+pK_b+\log C]$

$pOH=(1)/(2)[14+4.87+\log (0.0437)]$

$pOH=8.76$

$pH+pOH=14\n\npH=14-pOH\n\npH=14-8.76\n\npH=5.24$

Thus, the pH of the solution is, 5.24

What isotope has a mass number of 18 and an atomic number of 7

Answers

Answer:

nitrogen 18

nitrogen has an atomic number of 7

How to determine acid base reactions

Answers

Answer : Acid-base reaction is determined when hydrogen ion of an acid neutralize by the hydroxide ion of a base then it gives water.

Explanation :

Acid-base reaction : It is defined as the reaction in which an acid reacts with a base to give salt and water.

Acid-base reaction is determined when hydrogen ion of an acid neutralize by the hydroxide ion of a base then it gives water.

For example: When hydrochloric acid react with sodium hydroxide base to give sodium chloride salt and water.

The balanced acid-base reaction is:

$HCl+NaOH\rightarrow NaCl+H_2O$

An element is to a __ as an organ is to a ___

Answers

An element is to an atomas an organ is to a cell. Just as atoms are the fundamental building blocks of elements, cells are the basic units of living organisms.

Elements are composed of atoms, each characterized by a specific number of protons, neutrons, and electrons.

Similarly, organs are composed of cells, each with specialized structures and functions that collectively contribute to the overall function of the organ.

The analogy highlights the hierarchical organization of matter and life, emphasizing how complex structures are formed from simpler components.

Just as elements combine to create diverse substances, cells come together to form intricate organs essential for life processes.

Know more about organs:

brainly.com/question/13278945

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Answer:

An element is to a compound as an organ is to tissue

Explanation:

Which group is the most reactive?*
Alkaline Earth Metals
Alkali metals
Noble Gases
Lanthanides