Why is the atomic mass of most elements not a whole number?

Compare these two waves : a. the blue wave has a higher pitch, but the orange wave is louder. b. the blue and orange waves have the same volume, but the blue wave has a higher pitch. c. the blue and orange waves have the same pitch, but the blue wave is louder. d. the orange wave has a higher pitch, but the blue wave is louder.

Agas is contained in a thick walled balloon when the pressure changes from 1.21 atm to 2.52 the volume changes from 3.75 l to 1.72 l and the temperature change from 293k to blank k

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?