All but one of the following statements is true. Which one is not true? A mass (in grams) equal to the molecular mass (in atomic mass units) of a pure substance contains the same number of molecules, no matter what the substance is. Ten grams of a pure substance contains the same number of molecules, no matter what the substance is. One mole of any pure substance contains the same number of molecules. Ten grams of a pure substance contains twice as many molecules as five grams of that substance. Avogadro's number of molecules of a pure substance and one mole of the substance have the same mass.

All but one of the following statements is true. Which one is not true? A mass (in grams) equal to the molecular mass (in atomic mass units) of a pure substance contains the same number of molecules, no matter what the substance is. Ten grams of a pure substance contains the same number of molecules, no matter what the substance is. One mole of any pure substance contains the same number of molecules. Ten grams of a pure substance contains twice as many molecules as five grams of that substance. Avogadro's number of molecules of a pure substance and one mole of the substance have the same mass.