Module 4: Drivers of Reactions

Question 1

Always change temperatures to:

Answer 1

K

Question 2

Change mass to:

Answer 2

kg

Question 3

How can molar enthalpy be found?

Answer 3

Find the energy released per mole (energy / moles)

Question 4

What is the molar heat of combustion?

Answer 4

The heat liberated when one mole of the substance undergoes complete combustion with oxygen at a constant pressure of 100kPa

Question 5

How is the heat of combustion measured?

Answer 5

Rather than being the heat released, water is used and it is measured as the heat absorbed by the water (the law of conservation of energy)

Question 6

The breaking of bonds _______ and the forming of bonds ______

Answer 6

Requires energy
Releases energy

Question 7

What is Hess’s Law?

Answer 7

The law of conservation of energy (no matter how many steps, the enthalpy change is the same)

Question 8

What is sublimation?

Answer 8

the transition of a substance directly from a solid state to a gas state

Question 9

What is the heat of atomisation of an element?

Answer 9

It is the enthalpy change for the production of gaseous atoms from the element in its standard state at a pressure of 100.0kPa and at the temperature in question. It is usually expressed per mole of atoms.

Question 10

What is the reaction for photosynthesis?

Answer 10

6 carbon dioxide and 6 water –> glucose and 6 oxygen

Question 11

What is the equation for respiration?

Answer 11

Glucose and 6 oxygen –> 6 carbon dioxide and 6 water