Why does h2o have a lower melting point than mgo

What’s the scientific notation for the number 6,840,000,000

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?

In saturated organic compounds, all the bonds between carbon atoms are called?