Which of the following can be mixed in solution with NH2 to make a buffer? A. NH4Cl
B. NaOH
C. HNO3
D. NaCl

If a planet rotates 360 degrees during a 24 hour time period, what does that tell us about the planet? a. the middle of the planet is in darkness b. the seasons on the planet vary every day. c. the planet runs on a 12-hour time clock. d. the temperature on the planet varies daily.

Describe the interaction that occurs between two objects with the same electrical charge.

Which of the following units is not an official si unit? mole liter kilogram ampere