Calculate molecular mass of C2H5OH

Idon’t understand this page, can someone ?

If 10.g of agno3 is available, what volume of 0.25 m agno3 can be prepared

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?