Pure substances found on the periodic table are called what

Complete the sentence. the lower the hydrogen ion concentration, the the ph. higher lower closer to 7 closer to 0

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.

If i initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200 k, and then i raise the pressure to 14 atm and increase the temperature to 300 k, what is the new volume of the gas?