??H2 + O2 → 2H2 O plz help me

Achemist 16 drop copper metal from copper chloride solution. the chemist place is 0.50 g of aluminum foil in a solution containing 0.75 g of copper (ii) chloride. a single replacement reaction takes place. which statement explains the maximum amount of copper that the chemist can extract using this reaction?

The element that has the greatest electronegativity is

Suppose you wanted to make 100 grams of water. what is the molar mass of water (h2o)?