Energy And Chemical Reactions

Question 1

Define a calorie.

Answer 1

Energy required to increase the temperature of 1 gram of water by 1 degC.

Question 2

Define a joule

Answer 2

Energy required to apply a force of 1 newton through a distance of 1 metre

Question 3

How much a calorie is worth in joules?

Answer 3

4.186 joules

Question 4

What is a bond dissociation energy?

Answer 4

Average energy change required to break a mole of a given chemical bond

Question 5

What is one mole?

Answer 5

Number of atoms that make 12g of carbon 12 i.e. Avogadro’s constant = 6.022 x 10^23

Question 6

How much energy required to break a mole of OH bond?

Answer 6

463 kJ

Question 7

What is required for a reaction to occur?

Answer 7

Collision of molecules
In the correct orientation
With enough energy - activation energy

Question 8

Laws of thermodynamics

Answer 8

1) total energy of the universe is always conserved

2) the universe tends towards maximum disorder

Question 9

State the Gibb’s free energy equation

Answer 9

[Delta]G = [delta]H - T[delta]S

Question 10

What is the relationship between the type of reaction (exer vs endothermic) and its deltaG value?

Answer 10

Exergonic processes have negative deltaG - free energy released available to do work

Endergonic processes have positive deltaG - free energy consumed by the reaction

Both processes must be coupled to one another

Question 11

Give an example of exergonic reactions

Answer 11

Fermentation of glucose

Oxidation of ethanol

Question 12

How much free energy is generated per mole of glucose?

Answer 12

-2870 kJ per mole

Question 13

SIgn of delta G (thermodynamics) tells us about

Answer 13

How likely a reaction is

Direction of a reaction

Whether they provide or require energy

Question 14

Kinetics tell us whether…

Answer 14

The reaction will go to completion

Molecular mechanism of the reaction

Question 15

Zero order rate ?

Answer 15

Zero order: rate = -k

– independent of reactant concentration

Question 16

First order rate?

Answer 16

First order: rate = -k[A] or –k[B]

- if we double [A] or [B], we double the rate

Question 17

Second order rate?

Answer 17

Second order: rate = -k[A]2 or –k[A][B] or –k[B]2

– If we double [A], we quadruple the rate

Question 18

What acts as a currency of energy in the cell?

Answer 18

ATP