Actual question from source:-
A 3.96x10-4 M solution of compound A exhibited an absorbance of 0.624 at 238 nm in a 1.000 cm cuvette. A blank had an absorbance of 0.029. The absorbance of an unknown solution of compound A was 0.375. Find the concentration of A in the unknown.
Answer:
Molar absorptivity of compound A = 
Explanation:
According to the Lambert's Beer law:-
Where, A is the absorbance
l is the path length
is the molar absorptivity
c is the concentration.
Given that:-
c = 
Path length = 1.000 cm
Absorbance observed = 0.624
Absorbance blank = 0.029
A = 0.624 - 0.029 = 0.595
So, applying the values in the Lambert Beer's law as shown below:-
<u>Molar absorptivity of compound A = </u>
Because their atoms and molecules are held together firmly by the strong inter molecular forces
The ch4 molecule exhibits hydrogen bonding.
This statement is false. A CH4 molecule do not have a hydrogen bonding instead it has dipole dipole attraction.
Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom.
This would be a true statement. A hydrogen bond is present when an atom of hydrogen shares electrons with O, N or F atom.
A hydrogen bond is equivalent to a covalent bond.
This is a false statement. A hydrogen bond is an intermolecular force of attraction while covalent bond is a intramolecular force. So, they would mean different things.
a hydrogen bond is possible with only certain hydrogen-containing compounds.
This would be true. Without the presence of an hydrogen atom definitely there would be no hydrogen bond.
a hydrogen atom acquires a partial positive charge when it is covalently bonded to an f atom.
This would be true since a HF is a polar molecule.
Answer: Atoms form chemical bonds to satisfy the<u> Octet</u> rule and to become <u>stable.</u>
Explanation:
The tendency of atoms to attempt to get a noble gas configuration that is eight valence electrons is said to be octet rule. This is done to attain noble gas configuration and stability.
In order to attain stability the atoms tends to have eight electrons in its valence shell which can be obtained by either by sharing of electrons or complete transfer of electrons.
For example : As we know that the sodium has one valence electron, so if giving it up then the result in the same electron configuration as the neon and chlorine has seven valence electrons, so if it takes one it will have eight and the result in the same electronic configuration as the argon which is stable.
