I'm crying because no one helps me on this website. - what reaction is this CaCO₃ -> CaO + CO₂

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.

Calculate the percent composition by mass of each element in al(oh)3. use at least three significant figures.

On the periodic table, elements are arranged by which of the following. a. mass numbers. b. increasing atomic number. c. alphabetical order. or d. density