Fichas
Chemistry Unit 5 flashcards: arenes, benzene
Fichas del conjunto (22)
- 1Benzene propertiesCharacteristic odour
Immiscible in water
\(C_6H_6\)
colourless liquid
High C:H ratio - 22 pieces of evidence against the Kekule structure1) Substitution and addition reactions do not occur easily like in alkenes.
Thermochemical evidence H formation is less positive than expected suggesting it is more stable than the proposed structure. - 3What does the difference between enthalpy of hydrogenation of cyclohexene and benzene show?The energy taken in to overcome the stable benzene resonance structure.
- 4What is the bond length in benzene?0.139nm
- 5Describe the arrangement of electrons in benzeneEach C forms a sigma bond with adjacent C atoms forming a planar carbon hexagonal skeleton. Each C then has 1 p orbital containing 1 electron and the orbital lobes fuse to form 2 areas of delocalised electron density above and below the carbon skeleton.
- 6What do you see when benzene is burnt in air?A smoky yellow flame
- 7Benzene with bromine in UV is what type of reaction?Free-radical addition
- 8What do halogen carrier catalysts do to \(Br_2\) molecules?Polarise it
- 9Does benzene react with conc nitric acid on its own?No
- 10Which is a stronger acid sulphuric or nitric?Sulphuric
- 11Temperature conditions for nitration of benzeneBelow 55\(\omicron\)
- 12Method for nitrating benzeneAdd benzene dropwise from a tap funnel to nitrating mixture in a cold flask.
- 13What occurs when nitrating benzene if the temperature rises above 55?Multiple substitution
- 14Properties of nitrobenzeneToxic
Flammable
Pale yellow
Liquid
Aromatic
Odour of bitter almonds - 15What is fuming sulphuric acid?Conc. sulphuric with additional \(SO_3\)
- 16Name of mechanism for and conditions of alkylation and acylationElectrophillic substitution
Reflux - 17What type of reactions are acylation and alkylation called?Friedel Craft's reactions
- 18Conditions for addition of \(H_2\) to benzeneRaney Ni cat
150 degrees - 19Benzene activated and non-activated positions2,4,6 = activated
1, 3, 5 = non-activated - 20Does OH activate the ring?Yes
- 21What colour and state is 2, 4, 6 - tribromophenol?Solid white
- 22Phenol reacts with dilute nitric acid?Yes
Información
- Descripción
- A2 level (Unit 5) Chemistry Fichas sobre Chemistry Unit 5 flashcards: arenes, benzene, creado por J000D97 el 05/04/2015.
- Creado por
- J000D97
- Visitas
- 112
- Etiquetas
- Valoración