Hurry how did kelper describe the planets orbits ?

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)

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion

One of the few xenon compounds that form is cesium xenon heptafluoride (csxef7). how many moles of csxef7 can be produced from the reaction of 13.0 mol cesium fluoride with 12.5 mol xenon hexafluoride? csf(s) + xef6(s) csxef7(s)