FC 9-26 Flashcards
Define electronegativity.
The ability of an atom to attract the bonding electrons in a covalent bond.
What is the oxidation state of elements in elemental state?
0.
What is the oxidation state of a simple ion?
The charge on the ion.
Colour of Chlorine in aqueous solution.
Pale yellow.
Colour of Bromine in aqueous solution.
Orange.
Colour of Iodine in aqueous solution.
Brown.
Colour of Chlorine in Cyclohexane.
Pale yellow.
Colour of Bromine in Cyclohexane.
Orange.
Colour of Iodine in Cyclohexane.
Purple.
Aqueous Chlorine reacts with water in a disproportionation reaction to form what?
HCl and HOCl (Chloric acid).
Chlorine reacts with cold, dilute, aqueous NaOH in a disproportionation reaction to form what?
NaCl, NaClO (Sodium Chlorate) and Water.
How would you test for the Carbonate ion?
Add dilute nitric acid, and check for effervescence.
How would you test for the Sulphate ion?
Add barium nitrate, and check for a white precipitate.
How would you test for the ammonium ion?
Warm your unknown solution, and add aqueous NaOH. Check for ammonia gas being released using damp red litmus paper. It will turn blue if ion is present.
Define homologous series.
A series of compounds that have the same general formula and functional group, and which successive members differ by an extra CH2 unit.
Define isomers.
Different compounds with the same molecular formula.
Define structural isomers.
Compounds with the same molecular formula but different structural formula.
By what mechanism do alkanes and halogens react?
Radical substitution.
Define stereoisomers.
Isomers with the same structural formula but a different arrangement in space.
How can you form an alkene from an alcohol?
Dehydrate the alcohol under heating and in the presence of a sulphuric acid catalyst.
How can you form alkanes from alkenes?
React the alkene with hydrogen under heating, in the presence of a nickel catalyst.
How can you form haloalkanes from alkenes?
By reacting the alkene with a GASEOUS hydrogen-halide, or just with a halogen molecule like chlorine. These are electrophilic addition reactions. The reaction can be used as a test for unsaturation, as (orange) bromine water will go colourless if it reacts.
How can you form an alcohol from an alkene?
By reacting the alkene with steam and a phosphoric acid catalyst. This is called hydration.
Define electrophile.
An electron pair acceptor.
What determines the major product of an addition reaction?
The stability of the carbocation intermediate.
What can we do with waste polymers?
Recycle them, combust them, or use them as feedstock for the production of new plastics and other organic compounds.
Define nucleophile.
An electron pair donor.
What are the standard conditions?
1 atmosphere of pressure (100kPa) and 25^C.
Define enthalpy change of a reaction.
The enthalpy change when the number of moles shown in the equation react to form the products.
Define standard enthalpy change.
Enthalpy change of a reaction where all substances are in their standard state and standard conditions are used.
Define enthalpy change of combustion.
The enthalpy change when 1 mole of substance is completely burned in Oxygen.
Define enthalpy change of formation.
The enthalpy change when 1 mole of substance is formed from its elements.
Define enthalpy change of neutralisation.
The enthalpy change when 1 mole of water is formed from a neutralisation reaction.
State Hess’ law.
The enthalpy change of a reaction is independent from the route taken by the reaction, provided the conditions don’t change.
Why are some bond enthalpy values averages?
Because some bonds appear in many different compounds, so their bond enthalpy has to be calculated from a range of different compounds.
Define bond enthalpy.
The enthalpy change when 1 mole of bonds are broken, in molecules in gaseous state.
Why are enthalpy changes calculated from average bond enthalpies not 100% accurate?
3 reasons:
• Because enthalpies are average values.
• Because bond enthalpies aren’t calculated under standard conditions.
• Because bond enthalpies only predict gas phase changes.
What is the name of the oxidising agent, used to oxidise alcohols?
Warm, aqueous, acidic potassium dichromate.
What is the colour change when an alcohol is oxidised?
Orange to green, as the orange dichromate ions are reduced to green Cr 3+ ions.
State le Chatelier’s principle.
When one of the conditions affecting the position of a dynamic equilibrium is changed, the position of the equilibrium will shift in the direction that opposes the change.
