Chromium is a transition metal, and oxygen has an oxidation number of -2. Use this information to match each compound to its chemical formula.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

5 structural isomers

the isomers are:

n-exane :   ch3ch2ch2ch2ch2ch3

2-methylpentane :   ch3ch(ch3)ch2ch2ch3

3-methylpentane :   ch3ch2ch(ch3)ch2ch3

2,3-dimethylbutane :   (ch3)2chch(ch3)2

2,2-dimethylbutane :   (ch3)3cch2ch3