Erica throws a tennis ball against a wall, and it bounces back. Which force is responsible for sending the ball back to Erica?

A. the force that the ball exerts on the wall

B. the frictional force between the wall and the ball

C. the acceleration of the ball as it approaches the wall

D. the normal force that the wall exerts on the ball

What is the molar mass of a gas that has density of 2.054 g/l

Achemistry student needs to standardize a fresh solution of sodium hydroxide. he carefully weighs out of oxalic acid , a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in of distilled water. the student then titrates the oxalic acid solution with his sodium hydroxide solution. when the titration reaches the equivalence point, the student finds he has used of sodium hydroxide solution. calculate the molarity of the student's sodium hydroxide solution. be sure your answer has the correct number of significant digits.

How many moles of water are created if 3 moles of hydrogen react completely with excess oxygen?