standard enthalpy of formation

Question 1

What is the standard enthalpy of formation?

Answer 1

The standard enthalpy of formation, f
H ∆ ° , is the enthalpy change
when one mole of a substance is formed from its elements in their
standard states.

Question 2

The standard state of a substance is most stable when?

Answer 2

The standard state of a substance is its most stable state at a
pressure of 1 atmosphere and at a specified temperature, usually
taken as 298 K.

Question 3

What is the entropy of a system?

Answer 3

The entropy (S) of a system is a measure of the degree of disorder of
the system.

Question 4

The greater the degree of disorder leads to what happening to the entropy?

Answer 4

The greater the degree of disorder, the greater the entropy.

Question 5

Solids have a _____ disorder whilst gasses have a _______ disorder.

Answer 5

Solids have a lower disorder whilst gasses have a greater disorder.

Question 6

As Entropy increases what happens to the temperature?

Answer 6

As entropy increases the temperature increases

Question 7

There is a _______ ________ in _______ at the ________ point of a substance and an even more _____ and ______ change in entropy at the ________ point.

Answer 7

There is a rapid increase in entropy at the melting point of a
substance and an even more rapid and larger change in entropy at
the boiling point.

Question 8

What is the second law of thermodynamics?

Answer 8

The second law of thermodynamics states that the total entropy of a
reaction system and its surroundings always increases for a
spontaneous process.