Radium-221 has a half-life of 30 s. how long will it take for 95% of a sample to decay

In the following redox reaction which is the oxidizing agent and which is the reducing agent? alcl3 + na nacl + al

Plz mark brainliest 30 points 1) 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?

Hey guys so i need to know what is _nh3+> nh4oh ~chemistry~