NEED ASAP Only have 10 minutes left please help. 3. (50 points) What is the mass of 80.0L of Oxygen gas (02) at 2 atm and 50 ° C in temperature? Mass should be in units of grams.
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Calculate the number of molecules present in 0.750 mol of mgo.

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?

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.