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2 years ago

Which best describes an element?

Chemistry

2 answers:

maxonik [38]2 years ago

6 0

Answer:

An impure substance

Explanation:

Substance means: hard surface example: salt,corals,coal.

joja [24]2 years ago

4 0

An element is a pure substance

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Which of these have the same number of particles as 1 mole of water H2O

Fed [463]

Answer:

It is equal to Avogadro's number (NA), namely 6.022 x1023. If we have one mole of water, then we know that it will have a mass of 2 grams (for 2 moles of H atoms) + 16 grams (for one mole O atom) = 18 grams.

Explanation:

The question is not very much clear.

If you are asking for molecules then 1 mole water= 6.023 * 10^23

If you are asking for atoms then 1 mole water= 6.023 * 10^23 * 3

If you are asking for particles then,

So, in your example you would have one mole of water molecules. If you dissociated those water molecules, than you would end up with 2 moles of hydrogen atoms, and one mole of oxygen atoms.

I hope that was helpful!

H=1 proton,1 electron

O=8 protons,8 neutrons and 8 electrons

total particles in one H2O molecule-28

total no. of particles in 1 mole of water- 6.023 * 10^23 * 28

8 0

3 years ago

1. Show the mechanism for the main product for the monochlorination of 2-methylbutane. List all other products.

Bad White [126]

Answer:

See explanation below

Explanation:

First, we need to understand that the monochlorination of an alkane like this one, involves substitution of one of the atoms of hydrogen of the molecule for an atom of chlorine.

This reaction takes place when the alkane reacts with Cl₂ in presence of light or heat.

When this happens, the first step involves the breaking of the double bond of the chlorine to form the ion Cl⁻.

The next step involves the substraction of the hydrogen of the molecule by the Chlorine. This will leave the alkane with a lone pair available for reaction.

The third step, the alkane with the lone pair of electron substract a chlorine for the beggining and form the mono chlorinated product.

The final step involves forming the remaining products with the remaining reagents there.

In the picture attached you have the mechanism and product for this reaction:

3 0

3 years ago

Read 2 more answers

In the compound AbO3, the ratio of aluminum to<br> oxygen is

jasenka [17]

The compound is Al2O3. The ratio of aluminum to oxygen is 2:3.

3 0

3 years ago

You are given a solution that is 518 mM lactose. You need to make up 4.5 L of 16.7 mM solution. What volume do you need to trans

OLga [1]

Answer:

The volume you need to transfer from the stock solution is 0.145 l

Explanation:

Since the number of moles of lactose in the volume of stock solution that you transfer will be the same as the number of moles of lactose in the final solution, you can use this expression:

number of moles in volume to transfer = number of moles in the final solution

Since number of moles = concentration * volume (if the concentration is expressed in molarity), then:

Ci * Vi = Cf * Vf

where:

Ci = concentration of the stock solution.

Vi = volume of the stock solution to be transferred.

Cf = concentration of the final solution

Vf = volume of the final solution

Then, replacing with the data:

518 mM * Vi = 16.7 mM * 4.5 l

Vi = 16.7 mM * 4.5 l / 518 mM

Notice that any concentration unit can be used, as long as the units of the concentration of the stock and final solution are the same.

4 0

3 years ago

What is a number at the bottom right of an element in a chemical equation called?

Ann [662]

Answer:

There’s a particular way of writing what’s in a molecule called a chemical formula. The chemical formulae for all the elements that form each molecule and uses a small number to the bottom right of an element’s symbol to stand for the number of atoms of that element. For example, the chemical formula for water is H 2 O.

Explanation:

7 0

3 years ago

Read 2 more answers