What is the difference between particles of a real and particles of ideal gasses

Which of the following pressures is equal to 760 mm hg? 2.0 atm 101.3 pa 101,300 kpa 101,300 pa

Why are people not able to skip a dive to the deepest part of the ocean

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?