Solid copper is burned in oxygen gas to make solid copper (ll) oxide

Idon’t understand this page, can someone ?

How are isotopes of the same chemical element alike? how are they different?

Clyde and marilyn are riding a roller coaster. during which section(s) of the track is their potential energy converted to kinetic energy? a. from point b to point c only b. from point b to point d only c. from point a to point b only d. from point a to point b and from point c to point d