<u>Answer:</u>
The mass of the atom depends on the sub atomic particles present in the nucleus of an atom.
That is, the protons and the neutrons.
Electrons are present around the nucleus and the mass is negligible since its mass is very very less.
<em>mass of a proton = 
</em>
<em>mass of a neutron = 
</em>
<em>mass of an electron = 
</em>
Mass number represents the mass of one particular isotope and it is a whole number for example, 
Mass number is 13 and atomic number is 6 for the carbon isotope C-13.
Atomic mass is different from mass number and it is a fraction since it is the average atomic mass of all the isotopes of an atom.
Atomic mass of C is 12.011 amu which we see in the periodic table is the average atomic mass of isotopes C-12, C-13 and C-14.
Explanation:
The electronegativity difference in C-C and C-H atoms is quite low. This means smaller the electron cloud. This further means larger bond length that is electron's are further from the nucleus. hence, higher potential energy of C-C and C-H bonds.
On the contrary, C-O and H-O have large difference in electronegativity( O is high electronegative element) . This means smaller bond length. Electron's near the nucleus. Thus, lower potential energy of bonds.
The reaction between the reactants would be:
CH₃NH₂ + HCl ↔ CH₃NH₃⁺ + Cl⁻
Let the conjugate acid undergo hydrolysis. Then, apply the ICE approach.
CH₃NH₃⁺ + H₂O → H₃O⁺ + CH₃NH₂
I 0.11 0 0
C -x +x +x
E 0.11 - x x x
Ka = [H₃O⁺][CH₃NH₂]/[CH₃NH₃⁺]
Since the given information is Kb, let's find Ka in terms of Kb.
Ka = Kw/Kb, where Kw = 10⁻¹⁴
So,
Ka = 10⁻¹⁴/5×10⁻⁴ = 2×10⁻¹¹ = [H₃O⁺][CH₃NH₂]/[CH₃NH₃⁺]
2×10⁻¹¹ = [x][x]/[0.11-x]
Solving for x,
x = 1.483×10⁻⁶ = [H₃O⁺]
Since pH = -log[H₃O⁺],
pH = -log(1.483×10⁻⁶)
<em>pH = 5.83</em>
