If a chemist analyzes a 3.84g sample containing sand and table sugar, and recovers 1.43g of sand, what percent by mass of table sugar should the chemist report for this sample.

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.