What is 3 x 10^4 multiplied by 5 x 10^2?​

Need on both questionswill markbr />

A5.000 g sample of niso4 h2o decomposed to give 2.755 g of anhydrous niso4. what is the formula of the hydrate? what is the full chemical name for the hydrate? what is the molar mass of the hydrate? niso4•_h2o what is the mass % of water in the hydrate?

Asubstance is a good conductor of electricity which of the following best explains a probable position of the substance in a periodic table