Question

At STP, number of molecules in $5.6l$ of sulphur trioxide gas is _________.

Answer 1

At STP one mole of gas occupies $22.4L$.

So, no of molecules in $5.6l$ of $S{O}_3$ are $\frac{5.6}{22.4}\times Na=1.5\times {10}^{23}$