How do I find the number of molecules?

Margaret wants to make an orange flavored drink by stirring powdered drink mix into a glass of water. she doesn't like drinks that have small clumps of powdered solid in them, so she wants the drink to be a perfect solution. what factors should margaret not consider when deciding how much powder to add to her glass of water?

What is the mass defect of a mole of nuclei with 1.8 x 10^15 j/mol binding energy?

Which diagram shows the correct way to represent an ionic compound of magnesium oxide?