Mole ratio of aluminum to hydrogen gas - 2Al + 2H3PO4 —> 3 H2 + 2AlPO4

List four observations that indicate that a chemical reaction may be taking place

Consider the elements bromine and chlorine; which elements has a larger ionic radius ?

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the boiling of water, and explain your predictions. how does temperature affect the spontaneity of this process?