My brother needs help and the I didnt pass 7th sooo. Also couldn't find science so I but it as chemistry

If a molecule with a molecular formula of c13h18 is treated with an excess of h2 in the presence of finally divided pt metal under conditions required for maximum hydrogenation of the molecule to give a molecule with a formula c13h24, how many rings are in the molecule?

Is a pencil falling to the floor anon contact force, a force, or a contact force

Which one of the following bonds would you expect to be the most polar? a) b–h b) n–h c) p–h d) al–h e) c–h