Energy Considerations

Question 1

What are standard conditions?

Answer 1

pH is 7
298 Kelvin
1 M concentration

Question 2

What are features of reversible reactions?

Answer 2

Reversible reactions have have a small magnitude of ΔG.

Direction is dependant on concentration of product and reactions.

Question 3

How do energetically unfavourable reactions occur naturally?

Answer 3

Unfavourable reactions (+ve ΔG) can be coupled with an energetically favourable reaction such as ATP hydrolysis for the unfavourable reactions to occur.

Question 4

What are the First and Second Laws of thermodynamics?

Answer 4

First Law- Energy cannot be created of destroyed, but can be transformed.

Second Law- All processes must increase the entropy of the universe.

Question 5

Which is bond making and which is bond breaking?

Answer 5

Endothermic is bond breaking because you need to put energy in to break the bonds
Exothermic is bond making

Question 6

Bond enthalpy of the following:
C-H
C-C
C=C
C=O
Hydrogen bonds
van der Waals interactions

Answer 6

C-H : 412
C-C : 348
C=C : 610
C=O : 740
Hydrogen bonds : 12 - 30
van der Waals interactions : 0.4 - 4
(all in kJ/mol)