A portion of the periodic table is shown above Which element on the periodic table has properties that are most similar to those
of nitrogen (N) and which element has properties that are the least similar? Explain your reasoning.
2 answers:
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Answer:
Choice A. electrons would be required for displacing
of aluminum from a solution of
ions.
Assumption: by " ions" the question meant
with a charge of
on each ion.
Explanation:
The question states that the relative atomic mass of is
. In other words, each mole of
Therefore, that of silver that were formed would contain
of silver atoms.
Metallic silver would precipitate out of this solution only after these ions are turned into
atoms.
One ion carries one unit of positive electrical charge. On the other hand, each
carries one unit of negative electrical charge.
Therefore, each ion will need to gain one electron to form a neutral
atom.
.
At least of electrons would be required to turn
of
ions into that
of silver atoms (which have a mass of
.)
Hence, .
Unlike ions, each aluminum ion
carries three units of positive electrical charge. That is three times the amount of charge on one
ion. Therefore, three electrons will be required to turn one
ion to an
atom.
The question states that the relative atomic mass of is
. Therefore, each mole of
atoms would have a mass
. There would be
of atoms in that
of
.
It takes of electrons to turn one mole of
ions to one mole of
atoms. Hence,
of electrons would be required to produce that
of
atoms (which has a mass of
) from
ions.
That corresponds to the first choice, electrons.
Answer:
(B) 42.1%
Explanation:
The formula for the calculation of moles is shown below:
Given: For
Given mass = 15.5 g
Molar mass of = 78.0452 g/mol
<u>Moles of = 15.5 g / 78.0452 g/mol = 0.1986 moles</u>
Given: For
Given mass = 12.1 g
Molar mass of = 159.609 g/mol
<u>Moles of = 12.1 g / 159.609 g/mol = 0.0758 moles</u>
According to the given reaction:
1 mole of react with 1 mole of
0.1986 mole of react with 0.1986 mole of
Available moles of = 0.0758 moles
Limiting reagent is the one which is present in small amount. Thus, is limiting reagent. (0.0758 < 0.1986)
The formation of the product is governed by the limiting reagent. So,
1 mole of gives 1 mole of
0.0758 mole of gives 0.0758 mole of
Molar mass of = 95.611 g/mol
Mass of = Moles × Molar mass = 0.0758 × 95.611 g = 7.2473 g
Theoretical yield = 7.2473 g
Given experimental yield = 3.05 g
% yield = (Experimental yield / Theoretical yield) × 100 = (3.05/7.2473) × 100 = 42.1 %
<u>Option B is correct.</u>