To make the conversion that they ask us, we must take into account that a mole of any substance has 6.022x10^23 molecules, that is Avogadro's number. So the molecules contained in 1.75mol of H2O will be:
![\begin{gathered} MoleculesH_2O=GivenmolH_(2O)*(6.022*10^(23)molecules)/(1molH_2O) \\ MoleculesH_2O=1.75molH_(2O)*(6.022*10^(23)molecules)/(1molH_2O) \\ MoleculesH_2O=1.05*10^(24)moleculesH_2O \end{gathered}](https://img.qammunity.org/2023/formulas/chemistry/college/kl34bdrefbl2ahcwdwit6989uzljwfbx3j.png)
In 1.75 mol of H2O there are 1.05x10^24 molecules of H2O