Can someone explain this better and simpiler?

Cryolite, na3alf6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. start this question by first balance the chemical equation.1.) balance the equation: - alo3(s)+naoh(l)+hf(> na3alf6+h2o(g). 2.) if 17.5 kilograms of al2o3(s), 51.4 kilograms of naoh(l), and 51.4 kilograms of hf(g) react completely, how many kilograms of cryolite will be produced? 3.)which reactants will be in excess, (al2o3, naoh, or hf) 4.)what is the total mass of the excess reactants left over after the reaction is complete in kg?

Which is a characteristic of the electron sea model for metallic bonding? molecular orbitals overlap to produce bands. electrons flow easily between metal nuclei. electrons are in fixed positions in the orbitals. atomic nuclei are arranged in an irregular pattern.

Match the formula for the following compound:   magnesium sulfate heptahydratemgs·7h2omg2so4·7h2omg(s o4)2·7h2omgso4·7h2o