If some salt were accidently spilled as it was transferred from the balance to the cup would your calculated enthalpy of solution of the salt be too high or too low

In the millikan oil drop experiment they determined that every drop had a charge which was a while number multiple of -1.60x10^-19. if a drop has a total charge of -9.60x10^-19 then how many excess electrons are contained within the drop?

Classify this reaction: 2al+n2-> aln.

What causes most sediment to wash or fall into a river