PLEASE HELP ASAP Which of the following is an example of work.
O A pencil laying on top of a desk.
O A dog wagging its tail.
O A box sitting on the floor.
O A car that is parked.

What is conserved in the reaction shown below? h2(g) + cl2 (g) --> 2hcl(g)a. mass onlyb. mass and moles onlyc. mass, moles, and molecules onlyd. mass, moles, molecules, and volume