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Salsk061 [2.6K]
3 years ago
5

Periodic table, chemistry questions

Chemistry
1 answer:
ehidna [41]3 years ago
7 0

Answer:

Explanation:

The Lanthanides were first discovered in 1787 when a unusual black mineral was found in Ytterby, Sweden. This mineral, now known as Gadolinite, was later separated into the various Lanthanide elements. In 1794, Professor Gadolin obtained yttria, an impure form of yttrium oxide, from the mineral.

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How many grams of fluorine are contained in 8 molecules of boron trifluoride?
Lelu [443]
<h3>Answer:</h3>

             7.57 × 10⁻²² g of F

<h3>Solution:</h3>

Data Given:

                 Number of Molecules  =  8

                 M.Mass of BF₃ =  67.82 g.mol⁻¹

                 Mass of Fluorine atoms  =  ?

Step 1: Calculate Moles of BF₃

           Moles  =  Number of Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹

Putting value,

            Moles  =   8 Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹

            Moles  =  1.33 × 10⁻²³ mol

Step 2: Calculate Mass of BF₃:

                   Moles  =  Mass ÷ M.Mass

Solving for Mass,

                   Mass  =  Moles × M.Mass

Putting values,

                   Mass  =  1.33 × 10⁻²³ mol × 67.82 g.mol⁻¹

                   Mass  =  9.0 × 10⁻²² g

Step 3: Calculate Mass of Fluorine Atoms:

As,

                         67.82 g BF₃ contains  =  57 g of F

So,

                    9.0 × 10⁻²² g will contain  =  X g of F

Solving for X,

                       X =  (9.0 × 10⁻²² g × 57 g) ÷ 67.82 g

                        X  =  7.57 × 10⁻²² g of F

4 0
3 years ago
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The Lewis Dot Structure rule states that
ivolga24 [154]

Answer:

S= 32, or the total number of valence electrons for silicon tetrachloride

Explanation:

I drew the lewis dot structure to solve this

8 0
1 year ago
What does the chemical formula CaCI2 show about the compound or represents?
atroni [7]

Answer:

Two elements because Can is one element and Cl is another. The two is a coeficient that states how many of that element there is.

I hope this helps you!!!

8 0
3 years ago
In which atmospheric layer is the ozone layer?
drek231 [11]

Answer:

stratosphere

Explanation:

5 0
2 years ago
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What kind of electrical charges do protons,electrons, and neutrons have?​
Vinil7 [7]

<em><u>Protons</u></em><em><u> = Positive Charge</u></em>

<em><u>Neutrons</u></em><em><u> = Neutral Charge/No Charge</u></em>

<em><u>Electrons</u></em><em><u> = Negative Charge</u></em>

<em>This one's simple: electrons have a negative charge, protons have a positive charge and neutrons — as the name implies — are neutral.</em>

<u><em>Protons</em></u>

<em>Elements are differentiated from each other by the number of protons within their nucleus. For example, carbon atoms have six protons in their nucleus. Atoms with seven protons are nitrogen atoms. The number of protons for each element is known as the atomic number and does not change in chemical reactions. In other words, the elements at the beginning of a reaction -- known as the reactants -- are the same elements at the end of a reaction -- known as the products.</em>

<em />

<em><u>Neutrons</u></em>

<em>Although elements have a specific number of protons, atoms of the same element may have different numbers of neutrons and are termed isotopes. For example, hydrogen has three isotopes, each with a single proton. Protium is an isotope of hydrogen with zero neutrons, deuterium has one neutron, and tritium has two neutrons. Although the number of neutrons may differ between isotopes, the isotopes all behave in a chemically similar manner.</em>

<em />

<u><em>Electrons</em></u>

<em>Electrons are not bound as tightly to the atom as protons and neutrons. This allows electrons to be lost, gained or even shared between atoms. Atoms that lose an electron become ions with a +1 charge, since there is now one more proton than electrons. Atoms that gain an electron have one more electron than protons and become a -1 ion. Chemical bonds that hold atoms together to form compounds result from these changes in the number and arrangement of electrons.</em>

4 0
3 years ago
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