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docker41 [41]
3 years ago
13

Use the periodic table to identify the number of core electrons and the number of valence electrons in each case below.

Chemistry
1 answer:
Harman [31]3 years ago
5 0

Can you please add a picture of the case??

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Boron has primarily two isotopes, one with an atomic mass of 11.0 amu and another with an atomic mass of 10.0 amu. If the abunda
Masja [62]

Answer:

The atomic mass of the boron atom would be <em>10.135</em>

Explanation:

This is generally known as relative atomic mass.

Relative atomic mass or atomic weight is a physical quantity defined as the ratio of the average mass of atoms of a chemical element in a given sample to the atomic mass of 1/12 of the mass of a carbon-12 atom. Since both quantities in the ratio are masses, the resulting value is dimensionless; hence the value is said to be relative and does not have a unit.

<em>Note that the relative atomic mass of atoms is not always a whole number because of it being isotopic in nature.</em>

  • <em>Divide each abundance by 100 then multiply by atomic mass</em>
  • <em>Do that for each isotope, then add the two result. Thus</em>

Relative atomic mass of Boron = (18.5/100 x 11) + (81/100 x 10)

                                                 = 2.035 + 8.1

                                                 = 10.135

5 0
3 years ago
What material is the source for commercial production of each of the following elements:(a) aluminum;
AleksandrR [38]

The material which is used as source for commercial production aluminum is bauxite.

The aluminum can be extracted from bauxite ore by the process of Bayer process.

In the Bayer process, bauxite ore is heated in the pressure vessel along with a caustic soda solution (sodium hydroxide) at a temperature between 150 to 200 °C. At this temperatures, the aluminium is dissolved in the solution as sodium aluminate in the extraction process. After separation of the residue by filtering, when the liquid is cooled gibbsite is precipitated and then it is seeded with fine-grained aluminum hydroxide crystals from previous extractions. The precipitation take 7-19 days without the addition of seed crystals.

This extraction process converts the aluminium oxide to soluble sodium aluminate, NaAlO2, which afterward converted into aluminum hydroxide and then into aluminum oxide.

Thus, we concluded that the material which is used as source for commercial production aluminum is bauxite ore.

learn more about ore:

brainly.com/question/10306443

#SPJ4

3 0
2 years ago
It was observed that magnesium sulphate was present in tap water ,which hardness might that be​
astraxan [27]

Answer:

Calcium sulphate is the right answer for this question.

It is because calcium sulphate helps to obtain the hardness in water. hardness.

The presence of this resource is a main reason for permanent hardness.

Hard drinking water has moderate health benefits, but can pose serious problems for the industrial settings.

Explanation:

8 0
2 years ago
How do I do this and what are the answers?
vodka [1.7K]
I cannot see your question to help you... sorry
6 0
3 years ago
Using the molarity equation, calculate how many grams of salt you need in order to make 80ml of a 2M solution (MW = 58.44g/mole)
ollegr [7]

Answer:

9.35g

Explanation:

The molarity equation establishes that:

\textrm{molarity}=\frac{\textrm{moles  of solute}}{\textrm{liters of solution}}

So, we have information about molarity (2M) and volume (80 ml=0.08 l), with that, we can find the moles of solute:

\textrm{moles of solute}=\textrm{molarity}*\textrm{liters of solution}

\textrm{moles of solute}= 0.08 \textrm{ l} *2\textrm{ M} = 0.16 \textrm{ mol}

The  mathematical equation that establishes the relationship between molar weight, mass and moles is:

\textrm{molar weight}= \frac{\textrm{mass}}{\textrm{moles}}

\textrm{MW}= \frac{\textrm{m}}{\textrm{n}}

We have MW (58.44g/mole) and n (0.16 mol), and we need to find m (grams of salt needed) to solve the problem:

\textrm{m} = \textrm{MW * n}= 58.44\frac{\textrm{g}}{\textrm{mol}} * 0.16 \textrm{ mol} = 9.35 \textrm{ g}

8 0
4 years ago
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