What are the three main classes of elements? provide two physical properties for each class of elements

What is the volume occupied by 10.0 dm3 of gas at standard pressure after it has been compressedat constant temputure to 500.0 kpa?

How does the atmosphere to make earth livable? check all that apply. causes the seasons contains oxygen provides warmth creates important nutrients blocks harmful energy from the sun plz like !

Which one of the following is an oxidation-reduction reaction? naoh + hno3 --> h2o + kno3 naoh + hno3 --> h2o + kno3 so3 + h2o --> h2so4 cacl2 + na2co3 --> caco3 + 2 nacl ch4 + 2 o2 --> co2 + 2 h2o al2(so4)3 + 6 koh --> 2 al(oh)3 + 3 k2so4