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4 years ago

Why must pencil be used to draw on paper in paper chromatography

Chemistry

2 answers:

LUCKY_DIMON [66]4 years ago

3 0

Hey there!

The reason why a pencil must be used to draw in a paper chromatography is because its meant to split up the mixture of compounds into its sub parts.

Hope this helped you

Tobey

labwork [276]4 years ago

3 0

Because ink in a pen would be seperated into it's different components on the chromatography paper. Graphite pencils just... don't dissolve like that, they aren't soluble like ink. Graphite would not seperate on the paper, whilst ink would.

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All weather is energy in motion. Where does the energy come from

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Answer:

The Sun radiates huge amounts of energy. Only a small portion of that energy hits the Earth, but it is enough to light our days, heat our air and land, and create weather systems over the oceans. Most of the energy you will learn about comes from the Sun. The Earth also gives off energy.

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3 years ago

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A fecal transplant can work to cure a patient infected with a very harmful bacteria, such as C. difficile.

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3 years ago

If 1000g of water from Luboc River contains 0.0075g of Ca2+ ion, what is the concentration in ppm by mass of Ca2+ present in Lub

marin [14]

7.5 ppm

<h3>Further explanation</h3>

Given

1000 g of water

0.0075g of Ca²⁺ ion

Required

the concentration in ppm by mass of Ca²⁺

Solution

ppm = part per million

solvent = water ⇒ ppm = 1 mg/L(water density is 1 kg / L) or mg/kg

Convert g to mg of Ca²⁺ ion :

0.0075 g = 7.5 x 10⁻³ g = 7.5 mg

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3 years ago

A fossil you are radiometrically dating contains 4 micrograms of Uranium 235 and 4 micrograms of Lead 207. Uranium 235 decays to

Rzqust [24]

The rate at which radioactive substances disintegrate is a constant for a

given radioactive material.

The fossil is 710 million years old.

Reasons:

The half-life of a radioactive material is the time it takes half of the nucleus

of a radioactive material to disintegrate into other forms of materials

through the given off of energy and particles.

The half life of Uranium 235 = 710 million years

The product of the decay of Uranium 235 = Lead 207

The mass of Uranium 235 in the fossil = 4 micrograms

The mass of Lead 207 in the sample = 4 micrograms

Therefore, the mass of Lead 207 in the fossil is equal to the mass of

Uranium 235, therefore, a minimum of half of the Uranium 235 has

decomposed, which gives;

The time of decomposition of the Uranium 235 = 1 Half life = 710 million years

The age of the fossil = The time in which the Uranium has been

decomposing = The time of decomposition = 1 half life of Uranium 235 = 710

million years

The age of the fossil = 710 million years

Using the formula for half-life, we get;

$\displaystyle N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}}$

The fossil contains initially only Uranium 235 with a minimum mass of 4 mg

+ 4 mg = 8 mg, which gives;

N₀ = 8 mg

N(t) = The current mass of Uranium 235 = 4 mg

$\displaystyle t_{1/2}$ = 710 million years

$\displaystyle 4 = 8 \cdot \left (\dfrac{1}{2} \right )^{\dfrac{t}{710}$

$\displaystyle \frac{4}{8} = \frac{1}{2} = \left (\dfrac{1}{2} \right )^{\dfrac{t}{710}$

Therefore;

$\displaystyle \left( \frac{1}{2}\right)^1 = \left (\dfrac{1}{2} \right )^{\dfrac{t}{710}$

$\displaystyle 1 = {\dfrac{t}{710}$

t = 710

The age of the fossil, t = 710 million years

Learn more here:

brainly.com/question/20629992

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2 years ago

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Kitty [74]

Answer:

Gains

Explanation:

It gets more electrons

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3 years ago

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