How long does it take for a plant to grow

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?

Draw the lewis structure for the trisulfur s3 molecule. be sure to include all resonance structures that satisfy the octet rule.

What is a number added in front of a formula in order to balance the equation