Explain in terms of particle volume, why a sample of helium can not be compressed by a piston to a volume of zero. please can someone explain

What is the mass of 0.46 mol of mgcl2

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium

Which of the following describes the entropy change as a solution is made from a liquid and solid