Developing Fuels

Question 1

Enthalpy

Answer 1

Stored heat energy

Question 2

Enthalpy change of combustion

Answer 2

Enthalpy change when one mole of a substance is completely combusted under standard conditions

Question 3

Enthalpy change of neutralisation

Answer 3

Enthalpy change when one mole of water is formed when acid and alkali react under standard conditions

Question 4

Enthalpy change of formation

Answer 4

Enthalpy change when one mole of a substance is made from its elements under standard conditions

Question 5

Enthalpy change of neutralisation equation

Answer 5

H+ + OH- —> H2O

Question 6

Enthalpy change of combustion equation

Answer 6

… + …O2 —> …Co2 + …H2O

Question 7

Enthalpy change of combustion experiment

Answer 7

measure:
initial + final T
initial + final mass
Volume of water

Question 8

Enthalpy change of two liquids experiment

Answer 8

Measure:
Volumes of liquid 1 and 2
Start T of liquid 1 and 2
Final T of liquid

Question 9

Enthalpy change liquid and solid

Answer 9

Measure:
Volume of liquid
Mass of solid
Start and final T

Question 10

procedural issues + how to fix

Answer 10

Calorimeter not in contact with the flame
-Adjust the height
Exp not under std conditions
-do under std conditions
Incomplete combustion
-Use fuels with fewer C atoms
Hard to read thermometer
-use digital thermometer

Question 11

Hess Cheat

Answer 11

Only for enthalpy of formation
Sum of prods - sum of reactants

Question 12

Bond enthalpy values

Answer 12

For breaking one mole of bonds in gaseous molecules

Question 13

Why is bond enthalpy inaccurate

Answer 13

-The values are averages
-Reactants and Products might not be gases

Question 14

Bond angle in an alkane

Answer 14

Always 109.5

Question 15

Alkane reactions (3)

Answer 15

-Combustion
-Cracking
-Radical Substitution

Question 16

Homogenous Catalyst

Answer 16

Reactants and catalyst in the same state
-rxn involves multiple steps
-Catalyst may form intermediate

Question 17

Heterogenous Catalyst

Answer 17

Reactants and catalyst in a different state
-normally a solid
-Involves adsorption

Question 18

Heterogenous Catalyst 4 stage mechanism

Answer 18

Reactants adsorb onto the surface of the catalyst
Bonds in the reactants weaken and break
New bonds form to make products
Products desorb/leave

Question 19

Catalytic converters

Answer 19

Remove CO
-from incomplete combustion
Remove NO
-From N2 and O2 reacting at high temps and pressures
Remove unburnt hydrocarbons
-Incomplete combustion

Question 20

Catalytic Converter equation

Answer 20

CO + NO —> CO2 + (1/2)N2

Question 21

Structural Isomers

Answer 21

Same molecular formula but different structural formula

Question 22

Alkene reactions

Answer 22

-Combustion
-Electrophilic addition
-Addition polymerisation

Question 23

Electrophile

Answer 23

A species attracted to regions of high electron density
Forms a bond by accepting a pair of electrons

Question 24

Proof for C=C electrophilic addition mechanism

Answer 24

Add NaCl and the cl will take the place of the second Br

Question 25

Sigma and Pi bonds per bond

Answer 25

Single = one sigma
Double - one sigma, one pi
Triple = one sigma, two pi

Question 26

Ideal gas equation

Answer 26

Pv=nRT
P=Pa
V=m^3
n=No moles
R=8.314
T=Kelvin