Can somebody help me please :)

How do you know how many valence electrons are in a molecule?

telo118 [61]

1. by making a atomic configuration
2.by making a table of shells of k.l.m.n....
that's all

4 0

4 years ago

A target is shielded from a radioactive sample by a sheet of metal. What kind of radiation can pass through the sheet of metal

White raven [17]

Answer:

gamma rays only is the correct answer.

Explanation:

Every radiation has different penetrating power to penetrate in materials and the flow of particles through a material is called penetration power.

Penetrating power of the gamma rays is very high because it has no mass and charges that the reason it can travel far in the air than beta particles and alpha particles.

Alpha particles can be blocked by paper and beta particles can easily passes through paper but it cannot pass through aluminum sheet whereas gamma particles are hardest to blocked, gamma particles can be blocked by heavy shielding.

Thus the radiation can pass through sheet of metak and hit the target is only gamma rays.

4 0

3 years ago

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It was calculated that 4.3mL of 0.417 M HCl is required to titrate 11.9 mL of 0.151 M Mg(OH)2. Show evidence 2 HCl(aq) + Mg(OH)2

Lapatulllka [165]

Answer:

See explanation.

Explanation:

Hello,

In this case, for the described chemical reaction:

2 HCl(aq) + Mg(OH)2(aq) → MgCl2(aq) + 2 H2O(l)

We can notice there is a 2:1 molar ratio between the moles of hydrochloric acid and magnesium hydroxide, therefore, at the equivalence point:

$n_{HCl}=2*n_{Mg(OH)_2}$

And in terms of volumes and concentrations we verify:

$V_{HCl}M_{HCl}=2*V_{Mg(OH)_2}M_{Mg(OH)_2}$

So we use the given data to proof it:

$4.3mL*0.417M=2*11.9mL*0.151M\\1.793=3.594$

Therefore, we can conclude the data is wrong by means of the 2:1 mole ratio that for sure was not taken into account. This is also supported by the fact that normalities are actually the same, but the nomality of magnesium hydroxide is the half of the hydrochloric acid normality since the acid is monoprotic and the base has two hydroxyl ions.

Best regards.

4 0

3 years ago

Draw a Lewis structure for H2O that obeys the octet rule if possible and answer the following questions based on your drawing. 1

Nataliya [291]

This is an incomplete question, here is a complete question.

Draw a Lewis structure for H₂O that obeys the octet rule if possible and answer the following questions based on your drawing.

For the central oxygen atom:

The number of lone pairs =

The number of single bonds =

The number of double bonds =

Answer : The Lewis structure for H₂O is shown below.

For the central oxygen atom:

The number of lone pairs = 4

The number of single bonds = 2

The number of double bonds = 0

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The representation of valence electrons of an atom by dots around the symbol of an element is said to be the Lewis-dot symbol.

In the representation of Lewis-symbol, one electron dot must put on each side of the element symbol then paired the electrons.

The given molecule is, $H_2O$

As we know that hydrogen has '1' valence electrons and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in $H_2O$ = 2(1) + 6 = 8

According to Lewis-dot structure, there are 4 number of bonding electrons and 4 number of non-bonding electrons.

For the central oxygen atom:

The number of lone pairs = 4

The number of single bonds = 2

The number of double bonds = 0

5 0

3 years ago

What liquids contain less than 80% percent water?

guapka [62]

It is corn syrup and milk.

7 0

3 years ago

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