In nature, X contains two isotopes with mass numbers 79 and 81. Calculate the percentage abundance of the isotopes ⁷⁹X and ⁸¹X.

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.

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab. 

Ithink it’s one of those things that you put the object on