Collision theory states that for a chemical reaction to occur the reacting particles must collide with one another. in order for collisions to be successful, reacting particles must collide with sufficient energy and in the correct orientation to produce a temporary intermediate product, the activated complex. energy is the minimum energy required for a successful collision.
a.)activation
b.) collision
c.)kinetic
d.)potential

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.