Calculate the number of atoms of oxygen present in $176 \ g$ of $CO_2$.

What is the total number of electrons present in $18 \ mL$ of water?

The total number of protons in $10 \ g$ of calcium carbonate is $(N_0 = 6.023 \times 10^{23})$

How many moles of $Mg_3(PO_4)_2$ contain $0.25$ moles of oxygen atoms?

Among the following,choose the ones with an equal number of atoms.
$A$. $212 \ g$ of $Na_2CO_3(s)$ [molar mass $= 106 \ g/mol$]
$B$. $248 \ g$ of $Na_2O(s)$ [molar mass $= 62 \ g/mol$]
$C$. $240 \ g$ of $NaOH(s)$ [molar mass $= 40 \ g/mol$]
$D$. $12 \ g$ of $H_2(g)$ [molar mass $= 2 \ g/mol$]
$E$. $220 \ g$ of $CO_2(g)$ [molar mass $= 44 \ g/mol$]
Choose the correct answer from the options given below.

Three $1 \ L$ flasks contain $N_2$,$Ne$,and $O_3$ gases respectively. At the same temperature and pressure,find the ratio of the total number of atoms present.