How to find the atomic number of an element

Moving down in a group, the electronegativity decreases due to an increase in the distance between the nucleus and the valence electron shell, thereby decreasing the attraction, making the atom have less of an attraction for electrons or protons.

5 0

2 years ago

1. Alexa and her family travelled 5 hours south east on 1-45 to crystal

Gre4nikov [31]

Answer:

Average speed = 68 mph

Explanation:

Given that,

Total distance traveled by the family, d = 340 miles

The family traveled 5 hours southeast.

We need to find her average speed. The speed of an object is given by the total distance covered divided by time taken. So,

$v=\dfrac{d}{t}$

Put all the values,

$v=\dfrac{340}{5}\\\\v=68\ mph$

So, her average speed is equal to 68 mph.

5 0

2 years ago

What is paper chromatography? Calculate the Rr value of a colored dye that traveled 52 mm on a chromatography strip while the so

Karo-lina-s [1.5K]

Answer:

Paper chromatography is a basic technique of chromatography. It consist in the separation of the mixe components using a solvent.

Explanation:

Paper chromatography is a basic technique of chromatography. It consists in the separation of the mixed components using a solvent.

Paper chromatography consists of put some dot of the mix using a glass capillary into a specialized paper, generally made of cellulose, this is called a stationary phase.

Then you put this paper into a camera of glass named, chromatography camera, where previously contain a solvent. The solvent also know as a mobile phase, the type can be defined before the test and involves a study of the kind of the mix, and the compound you want to separate.

The chromatography camera has to be closed all the time during the test, and you can't move at all because the movement of the solvent can alternate the result.

Very often, the solution of the solvent is a mix of different liquid substances with different polarities.

When the stationary phase put into the camera, the solvent starts to move up over the paper, until the separation of the compounds is observable.

the Rf is a value who relates the move of the mobile phase with the move of the distance traveled by the substance tested.

To undersant the paper chromatography, you can watch the images attached.

The first is an image of the chromatography camera.

The second one is an image of a cellulose paper after the chromatography is done. You can watch the dots who indicates the traveling of the compound across the paper.

The third one can show you the evolutions of paper chromatography, from the beginning to the end.

To calculate the Rf value you have to use the equation:

Rf = distance traveled by the substance/distance traveled by the solvent/

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3 0

2 years ago