2 Energetics and Enthalpy Changes

Question 0

What is the definition for the standard enthalpy change?

Answer 0

The enthalpy change that happens when one mole of a substance is completely combusted in oxygen under standard conditions

Question 1

What does effervescence mean?

Answer 1

Bubbles a lot

Question 2

What is the symbol for the standard enthalpy change of combustion?

Answer 2

C

Question 3

When working out standard enthalpy change what are the rules?

Answer 3

First must be one mole

Can halve diatomic molecules

Question 4

What is the definition for the standard enthalpy change of formation?

Answer 4

The enthalpy change when one mole of a compound is formed from its elements in their standard states

Question 5

Do elements have an enthalpy change for formation?

Answer 5

Nope

Question 6

When working out enthalpy change, what form of carbon must be used?

Answer 6

Graphite

C(graphite)

Question 7

What is the symbol for the standard enthalpy change of formation?

Answer 7

f

Question 8

What is the definition for the standard enthalpy change of atomisation?

Answer 8

The enthalpy change when one mole of its atoms in the gaseous state is formed from the element under standard conditions

Question 9

What is the symbol for standard enthalpy change of atomisation?

Answer 9

at

Question 10

Standard enthalpy changes of atomisation is and exothermic/endothermic process

Answer 10

Exothermic

Question 11

What doesn’t have a standard enthalpy change of atomisation?

Answer 11

Noble gases

Question 12

What is the definition of the energy change of neutralisation?

Answer 12

The enthalpy change of a reaction where one mole of acid is neutralised by an alkali in their standard states at 298K and in solutions containing 1moldm(3)

Question 13

What is the enthalpy of neutralisation for strong acids with strong bases?

Answer 13

-58kJmol

Question 14

What is the definition of Hess’ Law?

Answer 14

The enthalpy change is independent of the path taken

Question 15

What happens if you the opposite way in Hess’ Law?

Answer 15

You subtract the value of the enthalpy change

Question 16

What is ALWAYS produced as a result of combustion?

Answer 16

Carbon dioxide

Water

Question 17

What is the equation for energy change?

Answer 17

Mass (g) x specific heat capacity (JK[-1]g[-1]) x temperature change (K)

Question 18

What is the equation for working out standard enthalpy change?

Answer 18

Sum of bonds broken - sum of bonds made

Sum of enthalpy change of formation (products) - sum of enthalpy change of formation (reactants)

Question 19

What is the equation for the number of moles?

Answer 19

Mass in g/mass of 1 mile
Volume gas dm(3)/24dm(3)
Concentration x volume

Question 20

What does the term ‘enthalpy change of a reaction’ mean?

Answer 20

Heat energy that is released into the surroundings in an exothermic reaction

Question 21

What is the definition for lattice enthalpy?

Answer 21

Standard enthalpy change of formation of one mole of an ionic compound from its gaseous ions under standard conditions

Question 22

What is the definition for standard molar entropy change of atomisation?

Answer 22

The enthalpy change that takes place when one mole of gaseous atoms is formed from its elements in its standards state under standard conditions

Question 23

What is the definition of electron affinity?

Answer 23

Energy change when one mole of gaseous atoms acquire one mole of electrons to form a single negatively charged ion

Question 24

What is energetics?

Answer 24

Study on energy transfers between reacting chemicals and surroundings

Question 25

Does breaking bonds will require energy or release energy?

Answer 25

Require

Question 26

Does making bonds require or release energy?

Answer 26

Release

Question 27

Give an example of an exothermic reaction and an endothermic reaction

Answer 27

Exothermic – neutralisation | Endothermic – photosynthesis

Question 28

What is the definition for enthalpy change of reaction?

Answer 28

Exothermic reaction releases energy to the surroundings in the form of heat

Question 29

What is the system?

Answer 29

The reaction in which the changes are happening brackets products and reactants

Question 30

What is meant by the surroundings?

Answer 30

Outside the system

Question 31

What are the two sorts of boundaries and what do they prevent?

Answer 31

Closed prevents particles entering/leaving system | Isolated prevents particles and energy entering/leaving system

Question 32

What is the first law of thermodynamics?

Answer 32

Energy cannot be created or destroyed

Question 33

What happens to the energy transferred to surroundings?

Answer 33

Dissipated

Question 34

What is the principle of conservation energy?

Answer 34

The total energy content of the universe is constant

Question 35

What is the equation to work out the enthalpy change of a reaction

Question 36

What is the enthalpy change of an exothermic reaction?

Answer 36

Negative H(products)< H(reactants) Net decrease in potential energy of the system

Question 37

What is the enthalpy change of an endothermic reaction?

Answer 37

Positive H(products)> H(reactants) Net increase in potential energy of the system

Question 38

What does the enthalpy level diagram of an exothermic reaction look like?

Answer 38

_______ | |______

Question 39

What does the enthalpy level diagram of an endothermic reaction look like?

Answer 39

_____ | ____|

Question 40

What is thermochemistry?

Answer 40

The study of the quantities of heat during reactions

Question 41

What does enthalpy mean?

Answer 41

The energy content of the system held at constant pressure | Represented by H