The prefix $10^{18}$ is

Which is higher: the normal boiling point or the standard boiling point? Provide an example.

Which of the following units represents the largest amount of energy?

If the speed of light is $3.0 \times 10^{8} \,m s^{-1}$,calculate the distance covered by light in $2.00 \,ns$.

If the diameter of a carbon atom is $0.15 \,nm$,calculate the number of carbon atoms which can be placed side by side in a straight line across the length of a scale of length $20 \,cm$.

What is the $SI$ unit of density?