Reactivity 1.1 And 1.2 Additional

Question 1

What are the three types is systems?

Answer 1

Open - exchanges energy and matter with the surroundings

Closed - only nerdy is exchanged with the surroundings

Isolated - nothing can be exchanged

Question 2

Assumptions for experiments

Answer 2

Rate of heat loss is constant
Density of all solutions is the same as water
Ignore the specific heat capacity of the container

Question 3

What are the limitations of bond energies?

Answer 3

It’s an average of bonds in different molecules
All substance need to be in gaseous form

Question 4

How does bond enthalpy affect bond length or polarity?

Answer 4

Bond length - shorter bonds tend to be stronger (higher enthalpy)

Polarity - electron distribution in a bond, influencing overall bond strength depending on electronegativity difference

Question 5

Hess’s law

Answer 5

States that the enthalpy change for a chemical reaction is independent of the route taken

Question 6

Standard enthalpy of formation

Answer 6

Enthalpy change when 1.00 mol of a substance is formed from its elements in their standard states, under standard conditions

Question 7

Lattice enthalpy definition

Answer 7

Is when 1.00 mil of an ionic compound is decomposed into its ions in gaseous state under standard conditions

Question 8

Electron affinity definition

Answer 8

Enthalpy change when 1.00 mol of gaseous atoms gains 1.00 mol of electrons to form 1.00 mol of gaseous ions with a 1- charge, under standard conditions

Question 9

Enthalpy of atomisation definition

Answer 9

Is the enthalpy change when 1.00 mol of gaseous atoms are formed, under standard conditions

Question 10

What is complete combustion?

Answer 10

When fuels are burnt in excess oxygen

Question 11

Biofuels definition

Answer 11

Are derived from biomass that was once alive. There is a net 0 CO2 output unlike fossil fuels

Question 12

Fuel cells definition

Answer 12

A method to create a current from the reaction hydrogen and water or methanol and water. Climate friendly

As fuel enters the cell is becomes oxidised which sets up a potential difference or voltage within the cell

Question 13

Fossil fuels definition and what are the 3 main types?

Answer 13

Fossil fuels are the remains of creatures and plants that lived millions of years ago

3 main types are coal, natural gas and crude oil