In which Group do most of the elements have 8 valence electrons?

Defferent between crysttiline solid and amerphus solid

Alexxx [7]

Answer:

Crystalline solids have well-defined edges and faces, diffract x-rays, and tend to have sharp melting points. In contrast, amorphous solids have irregular or curved surfaces, do not give well-resolved x-ray diffraction patterns, and melt over a wide range of temperatures.

Explanation:

Hope this helped!

5 0

3 years ago

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Which major product is formed when Br2 and H2O are added to 2-methylpropene to give the bromohydrin?

lora16 [44]

Answer:

See explanation and image attached

Explanation:

The addition of hypohalous acids to alkenes follows the Markovnikov rule. This rule states that the negative part of the addendum is joined to the carbon atom with the least number of hydrogen atoms (more substituted carbon atom).

In the addition of hypohalous acids, the halogen is the positive end of the addendum and the OH^- is the negative end of the addendum. This explains the product shown in the image attached.

6 0

3 years ago

How many moles of 0.225 M CaOH2 are present in 0.350 L of solution?

weeeeeb [17]

Answer : The number of moles of solute $Ca(OH)_2$ is, 0.0788 moles.

Explanation : Given,

Molarity = 0.225 M

Volume of solution = 0.350 L

Formula used:

$\text{Molarity}=\frac{\text{Moles of }Ca(OH)_2}{\text{Volume of solution (in L)}}$

Now put all the given values in this formula, we get:

$0.225M=\frac{\text{Moles of }Ca(OH)_2}{0.350L}$

$\text{Moles of }Ca(OH)_2=0.0788mol$

Therefore, the number of moles of solute $Ca(OH)_2$ is, 0.0788 moles.

7 0

3 years ago

A chemical formula written above or below the yield sign indicates:

sweet-ann [11.9K]

I believe the correct answer from the choices listed above is option B. A chemical formula written above or below the yield sign indicates <span>that the substance is used as a catalyst. I am certain with this answer. Hope this helps. Have a nice day.</span>

3 0

3 years ago

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Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. Calculate the expected yield of

Lelu [443]

Answer:

53kg is the expected yield of lead

Explanation:

Firstly, in order to solve this question, we need to write the equation of reaction correctly. This is as follows:

PbO(s) + C(s) ---> Pb(l) + CO(g)

We proceed from here. We should get the limiting reactant but this can only be obtained by getting the number of moles of each reactant present.

The formula to use across all boards is that the number of moles is the mass of each of the reactant divided by the molar mass of each of the reactant.

For PBO, mass is 57kg = 57000g

Molar mass of PBO = 223.20g/mol

The number of moles is thus 57,000/223.2 = 255.37 moles

For carbon, mass is also 57kg = 57000g

Molar mass is 12g/mol

Number of moles of carbon = 57000/12 = 4750 moles

From the number of moles, we can see that the number of moles of Carbon is greater than that of PbO. This means that PbO is the limiting reagent.

Hence we use it to calculate percentage yield.

The number of moles of lead formed is the same of number of moles of lead oxide = 255.37 since we have mole ratio of 1 to 1

The molar mass of lead is 207.20g/mol

The mass of lead formed is = moles of lead formed * molar mass of lead = 207.20 * 255.37 = 52,912g which is approximately 53kg

Hence the expected yield is 53kg

6 0

3 years ago