How many hydrogen (H) atoms are there in this chemical formula? 3C5HgNNaO4

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

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

Molecular iodine, i2(g), dissociates into iodine atoms at 625 k with a first-order rate constant of 0.271 s−1. part a part complete what is the half-life for this reaction?