Question

The number of oxygen atoms present in 14.6g of magnesium bicarbonate $[Mg{(HC{O_3})_2}]$ is
(A) $6{N_A}$
(B) $0.6{N_A}$
(C) ${N_A}$
(D) $0.5{N_A}$

Answer 1

Hint : To answer this question, we first need to understand what atoms are. The smallest unit of ordinary matter that makes up a chemical element is an atom. Atoms that are neutral or ionized make up every solid, liquid, gas, and plasma. Atoms are incredibly small, measuring about 100 picometers in diameter.

Complete Step By Step Answer:
Molecular mass - The mass of a molecule is measured in Dalton’s and is called molecular mass. Because they contain various isotopes of an element, different molecules of the same substance may have different molecular weights.
Moles - A mole is the mass of a substance containing $6.023 \times {10^{23}}$ particles of that material. The mole is the SI unit for a substance's quantity. The symbol for it is mol. 1 mol of carbon-12 has a mass of 12 grammes and contains $6.023 \times {10^{23}}$ carbon atoms, according to definition (to 10 significant figures).
Molecular mass of magnesium bicarbonate is 146 grams
$no{\kern 1pt} .{\kern 1pt} {\kern 1pt} {\kern 1pt} of{\kern 1pt} {\kern 1pt} moles = \dfrac{{given{\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} weight}}{{molecular{\kern 1pt} {\kern 1pt} {\kern 1pt} weight}}$
Given weight is 14.6 grams
$no.{\kern 1pt} {\kern 1pt} {\kern 1pt} of{\kern 1pt} {\kern 1pt} moles = \dfrac{{14.6}}{{146}}$
$no.{\kern 1pt} {\kern 1pt} {\kern 1pt} of{\kern 1pt} {\kern 1pt} moles = 0.1$
Number of moles of oxygen in magnesium bicarbonate is $\dfrac{{16 \times 3 \times 2}}{{16}}$ (assuming one mole of magnesium bicarbonate)
Number of moles of oxygen in magnesium bicarbonate $= \;\;6$
Final number of oxygen moles with 0.1 moles of magnesium bicarbonate $0.1 \times 6 \times {N_A}$ .
So, the total number of oxygen atoms present in 14.6 grams of magnesium bicarbonate is $0.6{N_A}$ .
So the final answer is option (B) i.e., $0.6{N_A}$ .

Note :
Drinking bicarbonate-fortified water could help you maintain a healthy acid-base balance. Magnesium serves as a cofactor for over 300 enzymes. About half of the magnesium in the body is found in bone, where it plays an important role in calcium and bone homeostasis.