Consider the reaction:

a(g) + b(g) ? c(l)

in order for a reaction to be spontaneous under standard conditions, the reaction must:

result in an increase of the entropy of the system

this reaction could not be spontaneous under standard conditions

be exothermic

take place at high temperatures

take place in the presence of a catalytst

Ans : be exothermic

Explanation:

Fo rexample,   H2 (g) + O2 (g ) = H2O (l).   ∆H = -286 KJ/mol.  

This example shows the mixing up of two gases to form a liquid with the evolution of heat shown by the negative value of ∆H . Which clearly shows it is an exothermic reaction.

coral.

explanation:

coral. many marine organisms that produce calcium carbonate shells or skeletons are negatively impacted by increasing co2 levels and decreasing ph in seawater.