What is the density of a block of marble that occupies 228cm3 and has the mass of 987g

Explain why pure hydrogen cyanide does not conduct electricity, but become a conductor when it is dissolved in water? (at room temp, pure hcn exists as a volatile liquid)

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?

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains