Phosphoric acid is a triprotic acid (Ka1=6.9×10−3 M, Ka2=6.2×10−8 M, and Ka3=4.8×10−13 M) . To find the pH of a buffer composed of H2PO−4(aq) and HPO2−4(aq) , which pKa value would you use in the Henderson–Hasselbalch equation? pKa1=2.16 pKa2=7.21 pKa3=12.32 Calculate the pH of a buffer solution obtained by dissolving 16.0 g KH2PO4(s) and 27.0 g Na2HPO4(s) in water and then diluting to 1.00 L.

How did planetesmals form planets? a. they broke apart into smaller chunks.b. they collided and stuck together.c. they cooled and pulled ice together.d. they began to rotate.

Why did southern business leaders want to increase the number of slaves

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?