Looking at a potential energy diagram what is the name given to represent the amount of energy given off during an exothermal reaction?

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.

How do you know when a chemical reaction has occurred

Ab c or d ? i’m not sure what the answer is