How many water molecules are there in one drop of water $($Volume $= 0.0018 \ mL)$ at room temperature?

What is the mass in $kg$ of $5$ mole of acetic acid $(mol. mass = 60 \ g \ mol^{-1})$ (in $kg$)?

If every person on Earth is given $100$ molecules of sugar,how much sugar $(C_{12}H_{22}O_{11})$ is required? (Assume the population of Earth is $3 \times 10^{10}$ and the molar mass of sugar is $342 \ g/mol$)

$138 \ g$ of ethyl alcohol is mixed with $72 \ g$ of water. The ratio of mole fraction of alcohol to water is

Which has the maximum number of molecules?

The ratio of the number of oxygen atoms $(O)$ in $16.0 \ g$ ozone $(O_3)$,$28.0 \ g$ carbon monoxide $(CO)$,and $16.0 \ g$ oxygen $(O_2)$ is (Atomic mass: $C = 12$,$O = 16$ and Avogadro's constant $N_A = 6.0 \times 10^{23} \ mol^{-1}$)