An element's most stable ion forms an ionic compound with chlorine, having the formula XCl2. If the ion of element X has a mass
1 answer:
<u>Answer:</u> The unknown element X is calcium.
<u>Explanation:</u>
We are given:
An ionic compound having chemical formula =
The given compound is a neutral compound and in a neutral compound, the oxidation states are exchanged.
We know that:
Oxidation state of chlorine ion = -1
So, the oxidation state of X ion will be +2
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
Number of electrons = Number of protons - charge
We are given:
Mass number = 40
Number of electrons = 18
So, number of protons = Number of electrons + Charge
Number of protons = 18 + 2 = 20 = Atomic number
Hence, the unknown element X is calcium having atomic number '20'
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Answer:
a) Percentage by mass of carbon: 18.3%
Percentage by mass of hydrogen: 0.77%
b) Percentage by mass of chlorine: 80.37%
c) Molecular formula:
Explanation:
Firstly, the mass of carbon must be determined by using a conversion factor:
The same process is used to calculate the amount of hydrogen:
The percentage by mass of carbon and hydrogen are calculated as follows:
%C= 18.3%
%H=0.77%
From the precipation data it is possible obtain the amount of chlorine present in the compound:
= 0.43g AgCl
Let's calculate the percentage by mass of chlorine:
%Cl== 80.37%
Assuming that we have 100g of the compound, it is possible to determine the number of moles of each element in the compound:
Dividing each of the quantities above by the smallest (0.77mol), the subscripts in a tentative formula would be
≈ 2
≈3
The empirical formula for the compound is:
The mass of this empirical formula is:
mass of C + mass of H + mass of Cl= 24g +1+ 106.35 =131.35g
This mass matches with the molar mass, which means that the supscript in the molecular formula are the same of the empirical one.