How do you know a substance contains covalent bonds? how do you name them?

If 90.0 grams of ethane reacted with excess chlorine,how many grams of dicarbon hexachloride would form

How many moles of no2 will form when 3.3 moles of cu are reacted with excess hno3?

#7 how does the structure of amino acids allow them to form a polypeptide? each amino acid has an amino group and a carboxyl group. each amino acid has a hydrogen atom and a carboxyl group. each amino acid has a carboxyl group and an r group. each amino acid has an r group and a hydrogen atom.