If a steam engine does 500 J of useful work, how much work is needed to be put in if the efficiency rating is 18%?

What shape would a molecule with two bound groups and two lone pairs have?

How is energy related to the change of state represented by the model? atoms gain energy as a solid changes to a liquid. atoms gain energy as a solid changes to a gas. atoms lose energy as a solid changes to a liquid. atoms lose energy as a solid changes to a gas.

What element has similar physical and chemical properties as boron.