Find the number of moles present in $0.448 \ L$ of dihydrogen at $STP$. (in $mol$)

Which of the following has the smallest number of molecules?

What is the number of carbon atoms present in $0.35 \ mol$ of $C_6H_{12}O_6$?

$A$ sample of ammonium phosphate,$(NH_4)_3PO_4$,contains $6$ moles of hydrogen atoms. The number of moles of oxygen atoms in the sample is:

Two flasks $A$ and $B$ of $500 \ mL$ each are filled with $O_2$ and $SO_2$ respectively at $300 \ K$ and $1 \ atm$ pressure. Then the flasks contain:

Assertion $(A)$: Equal moles of different substances contain the same number of constituent particles.
Reason $(R)$: Equal weights of different substances contain the same number of constituent particles.
The correct answer is