New to learning this, could someone help?

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?

Which statements are true concerning mineral formation? check all that apply. the slower the cooling, the larger the crystals. the faster the cooling, the smaller the crystals. crystals formed from magma are smaller than crystals formed from lava. minerals can only form in solutions when the solution is heated deep underground. when a solution cools, elements and compounds leave the solution and crystallize as minerals. minerals formed from hot water solutions can form narrow channels in the surrounding rock.

Why do lunar and solar eclipse not happen every month