What is the percentage composition of chlorine in nacl

How is it possible for someone to put an ear to a wall and hear someone in the next room?     a.sound waves can travel though solids.    b.the waves travel from room to room via air.    c.there must be some air in the wall so the sound can travel through it.    d.sound waves change to electromagnetic waves and then back again.

Determine the total number of atoms in 1.0 mol of co2

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 14.0 mol cesium fluoride with 14.0 mol xenon hexafluoride? csf(s) + xef6(s) csxef7(s)