Choose words from the list to fill in the blanks in the paragraphs. Word List:
endothermic reaction
enthalpy
entropy
exothermic reaction
free energy
free energy of formation
Gibbs equation
heat of formation
heat of reaction
Hess's law
Kelvin temperature
standard heat of formation

The heat content of a substance is called its (1). The change
in this quantity that occurs during a chemical reaction is called
the (2) __, AH. If the chemical change is the production of a
compound from its elements, this quantity is called the
(3)
At 25°C and 1 atmosphere of pressure, it is called the
(4)
The sign of the quantity AH is positive in the case of an)
(5)
It is negative in the case of an)
(6)
When a reaction can be expressed as the algebraic sum of two
or more other reactions, its heat of reaction is equal to the alge-
braic sum of the heats of these other reactions. This relationship
is called (7)
A measure of the randomness of a system is its (8) If, in
any reaction, the change in this quantity is multiplied by the
19)
and subtracted from AH for the reaction, the result is
called the (10) of the reaction. If the reaction is the production
of a compound from its elements, the above result is called the
(11) of the compound. This relationship is expressed in the
(12)