mixing hydrochloric acid (HCI) and aqueous calcium hydroxide produces water and aqueous calcium chloride

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.

The answer is c - the principal of original lateral continuity. 

Answer///an early form of the atomic theory; dalton atomic theory;

Ican't see the chart but the density of both nickel and cobalt is 8.90 g/cm3, so it would be one of those.