Question

Absolute mass of a proton is equal to ________________.
A . $9.109 \times {10^{ - 31}}kg$
B . $- 1.602 \times {10^{ - 31}}kg$
C . $1.672 \times {10^{ - 27}}kg$
D .$1.674 \times {10^{ - 27}}kg$

Answer 1

- Hint: We have studied the Atomic structure of an atom where we are told an atom is made of three particle protons ,neutrons and electrons. Protons and neutrons have almost the same mass while electrons have smaller mass in comparison to protons and neutrons.

Complete step-by-step solution -
We know about mole concept where 1 mole means $6.022 \times {10^{23}}$(Avogadro’s number) ,In hydrogen atom one mole of the atom weighs $1.007g$ so we can say that each mole of protons in a hydrogen atom weights $1.007g$ . Production of proton can be done by removal of an electron from hydrogen atom $H \to {H^ + } + {e^ - }$ (Hydrogen atom→ proton +electron).So mass of proton is equals to the mass of hydrogen atom( As we neglect mass of electron because it is very small ).
Then we can have proton mass by dividing the weight of proton with the number of mole so,
$\Rightarrow \dfrac{{1.0079}}{{6.022 \times {{10}^{23}}}} = 1.672 \times {10^{ - 24}}g$
$\Rightarrow 1.672 \times {10^{ - 27}}kg$
So the absolute mass of proton is $1.672 \times {10^{ - 27}}kg$ or we can say that it has mass 1 amu (atomic mass unit) which is defined as 1/12 mass of an carbon atom who is in natural and unbounded state. This carbon atom is used as a reference in finding the atomic masses of atoms.

Note : Proton is that subatomic particle of atom which has positive charge and it exits in the nucleus of atom .Atomic mass of an atom refers to the weight of subatomic particles ( Electrons, Protons and Neutrons). The absolute charge on the neutron is 0. We have solved this problem as we know that hydrogen atom is helpful in finding the mass of proton and then we have divided the weight of proton with the number of moles.