Question

The relative atomic mass of fluorine is 19. What is the mass of 3 mol of fluorine gas?
(A) 110g
(B) 112g
(C) 114g
(D) 120g

Answer 1

Hint: Fluorine is an element which belongs to the halogen group. It has an atomic number of 17. In order to find the mass of 3 moles of fluorine gas, we must find the mass of one mole of Fluorine gas with relative atomic mass of Fluorine. Hence with that calculation for 3 moles of Fluorine gas.

Complete step by step solution:
> Fluorine is an element with atomic number 17. It belongs to the halogen group. It is the first element present in the halogen group. The electronic configuration of fluorine is given as, $$1s^{2}2s^{2}2p^{6}3s^{2}3p^5$$.
> What do you mean by relative atomic mass? Relative atomic weight can be defined as the ratio of average mass of the atoms of the chemical element in a given compound to the atomic mass constant. The atomic mass constant is the $$\frac{1}{12}$$ of the mass of the Carbon-12 atom.
> The relative atomic mass of fluorine, $$F$$ is given which is 19g.
> Relative atomic mass of Fluorine gas, $$F_2$$ is,
$$=2\times 19=38g$$
> One mole of $$F_2$$ has 38g
> Therefore, 3 moles of $$F_2$$ will have
$$=3\times 38=114g$$

> Therefore, the mass of 3 moles of Fluorine gas is 114g.

Hence, the correct answer is option (C) 114g.

Additional information:
- Fluorine is a pale yellow-green colour.
- It belongs to the p-block element.
- It is the first element of the halogen group.
- It is highly poisonous.
- It is chemically reactive and highly electronegative of all elements.
- It is used for the etching of glass.

Note:
- We have to remember that relative atomic mass and relative molar mass are not the same.
- Relative atomic mass is applicable only for the atoms.
- But relative molar mass is applicable to anything that can be present in moles.