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balu736 [363]
3 years ago
5

Why is it better to allow the solvent front to move almost to the top of a paper strip rather than stopping it at the halfway po

int during development
Chemistry
1 answer:
m_a_m_a [10]3 years ago
4 0

Answer:

To allow all the elements or compounds to separate complete.

Explanation:

In chromatography, the compounds need some space and time to separate, one from each other, if you  just use the half of the paper strip maybe you will not notice the different spots of compounds. Remember all the substances have different affinity for the solvents, that means, some react very quickly but others need more time as the colors that conform the black color in an ink.

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For 480. 0 mL m L of pure water, calculate the initial pH p H and the final pH p H after adding 2. 0×10−2 mol m o l of HCl H C l
Maslowich

Given that the volume of the pure water is 480 mL and the mole of HCl added to the water is 2×10¯² mole. Therefore, the Initial and final pH of the water are:

1. The initial pH of the pure water is 7

2. The final pH of the water is 1.38

<h3>What is pH ? </h3>

This is simply a measure of the acidity / alkalinity of a solution.

The pH measures the hydrogen ion concentration while the pOH measures the hydroxide ion concentration

<h3>pH scale </h3>

The pH scale is a scale that gives an understanding of the variation of the acidity / alkalinity of a solution.

The scale ranges from 0 to 14 indicating:

  • 0 to 6 indicates acid
  • 7 indicates neutral (pure water)
  • 8 to 14 indicate basic

<h3>How to determine the molarity </h3>
  • Volume = 480 mL = 480 / 1000 = 0.48 L
  • Mole of HCl = 2×10¯² mole
  • Molarity =?

Molarity = mole / Volume

Molarity = 2×10¯² / 0.48

Molarity = 4.17×10¯² M

<h3>Dissociation equation </h3>

HCl(aq) —> H⁺(aq) + Cl¯(aq)

From the balanced equation above,

1 mole of HCl contains 1 mole of H⁺

Therefore,

4.17×10¯² M HCl will also contain 4.17×10¯² M H⁺

<h3>How to determine the pH </h3>
  • Hydrogen ion concentration [H⁺] = 4.17×10¯² M
  • pH =?

pH = –Log H⁺

pH = –Log 4.17×10¯²

pH = 1.38

Learn more about pH:

brainly.com/question/3709867

6 0
2 years ago
Consider the chemical equation for the ionization of CH3NH2 in water. Estimate the percent ionization of CH3NH2 in a 0.050 M CH3
anyanavicka [17]

Answer:  The percent ionization of CH_3NH_2 in a 0.050 M CH_3NH_2(aq) solution is 8.9 %

Explanation:

CH_3NH_2+H_2O\rightarrow OH^-+CH_3NH_3^+

 cM                            0             0

c-c\alpha                       c\alpha            c\alpha

So dissociation constant will be:

K_b=\frac{(c\alpha)^{2}}{c-c\alpha}

Give c= concentration = 0.050 M and \alpha = degree of ionisation = ?

K_b=4.4\times 10^{-4}

Putting in the values we get:

4.4\times 10^{-4}=\frac{(0.050\times \alpha)^2}{(0.050-0.050\times \alpha)}

(\alpha)=0.089

percent ionisation =0.089\times 100=8.9\%

8 0
3 years ago
Could two objects with the same volume have different masses? Which, if either, would contain more matter?
kipiarov [429]

Answer:  Yes, two objects may have the same volume while having different masses. The object with a greater mass will be the one that contains more matter.

Explanation: Mass and volume are two different properties of matter. Mass is defined as the amount of matter that a body has. Volume is defined as the amount of space that a body occupies. Density is the property that relates mass with volume as

Density=Mass/Volume

and is defined as the amount of matter that exists in a certain amount of space.

Because mass and volume are independent from each other, we can say that two objects can have different masses and have the same volume.

<u>For example</u>, imagine two identical containers that weigh the same and that are capable of containing a volume of 1 liter each. Then, one of the containers is filled with water, while the other one is filled with mercury. In this case the volume of the water and the volume of the mercury will be the same: 1 liter, however, if we weigh the containers again, we will find that the one that has mercury is heavier than the one that has water. This is due to the density of mercury being higher than the density of water. In other words, 1 liter of mercury provides more mass than the mass provided by 1 liter of water.

Then, according to the definition of mass, the object that contains more matter will be the one that has more mass, in the case of our example, that would be the liter of mercury.

5 0
3 years ago
Which best describes the role of a secondary consumer in a food web? (3 points)
kodGreya [7K]

Answer: c

Herbivore that feeds on primary consumers

Explanation:

6 0
3 years ago
Read 2 more answers
In solids, the particles of matter are not in constant motion.
Vsevolod [243]
True because in a solid particles dont move so it wouldn't be in a constant motion. 
5 0
4 years ago
Read 2 more answers
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