Does each element have a unique chemical

Brainliesttt me asap! the below reaction can be categorized as more than one type of reaction. which reactions are these, and what are the types of reactions?

Plz mark brainliest 30 points1) find the momentum of a 12 kg snowball that is rolling with a velocity of 9 m/s.2) an 8 ball with a mass of .5 kg is sitting at rest. it is hit by the cue ball (1 kg) traveling at 2.5 m/s. if the cue ball is at rest after the collision, how fast is the 8 ball traveling after the collision? 3) two football players are running toward each other. if the offensive player is 75 kg and is running 8 m/s, how fast must the 60 kg defensive player run in order for the two players to hit and stop?

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.