Why are noontime shadows longer in winter than in summer?
same as my last question this is astronomy not chemistry.

100mg magnesium reacts with 20ml of 1.0m hcl

What type of reaction is shown below? check all that apply. 2h2o2 → 2h2o + o2 synthesis decomposition combustion

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?