Chemistry
Assertion (A): Atomic mass is expressed in atomic mass unit.
Reason (R): Atomic mass is defined as times the mass of carbon-12.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Mole Concept
1 Like
Answer
Both A and R are true but R is not the correct explanation of A.
Explanation — Atomic mass is expressed in atomic mass units [a.m.u.].
The relative atomic mass or atomic weight of an element is the number of times one atom of the element is heavier than times of the mass of an atom of carbon-12.
Relative atomic mass =
Therefore, both assertion (A) and reason (R) are true.
Atomic mass is expressed in atomic mass unit because atoms being extremely small cannot be weighed directly and conventional units of mass like kilograms or grams are not suitable for measuring them.
Hence, both assertion (A) and reason (R) are true but reason (R) does not correctly explain assertion (A).
Answered By
3 Likes
Related Questions
Assertion (A): Triatomic molecules consist of four atoms.
Reason (R): Monoatomic molecules contain only one atom.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): One litre of hydrogen weighs the same as one litre of oxygen.
Reason (R): One litre of hydrogen contains the same number of molecules as one litre of oxygen.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Sulphur is an octatomic molecule.
Reason (R): The number of atoms in a molecule of an element is known as atomicity.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): One mole of a gas occupies 24.4 litres at S.T.P.
Reason (R): The mass of one mole of a gas is equal to its molecular mass.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.