Organic Flashcards by Jade Keating

Formation of ethanoic acid impurities

Water, ethanal and ethyl ethanoate

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Reflux distillation

Involves condensing the vapour from a boiling liquid in such a way as to return the condensed material to the reaction vessel. In this way, a reaction may be carried out at quite a high temperature while preventing the loss any reactants or products

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Mass=

Volume x density

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Moles=

Mass / molar mass

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A homologous series

A family of compounds with the same general formula

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Structural Isomers

Are compounds that have the same molecular formula and different structural formulas

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Impurities present in ethyne gas

Hydrogen sulfide and phosphine

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An exothermic reaction

Gives out heat to surroundings

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An endothermic reaction

Takes in heat from surroundings

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The heat of reaction of a chemical reaction

Is the heat in kilojoules released or absorbed when the number of moles indicated in the balanced equation describing the reaction react completely

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Bond Energy

The amount of energy in kilojoules need to break one mole of bonds of the same type in the gaseous state

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The heat of combustion of a substance

Is the heat change in kilojoules when 1 mole of a substance is completely burned in excess oxygen

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The kilogram calorific value

Is defined as the heat energy produced per kilogram of fuel

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The heat of formation

Of a substance in the heat change in kilojoules when 1 mole of a substance is formed from its elements in their standard states

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The law of conservation of energy states that…

Energy cannot be created or destroyed only changed from one form to another

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Hess’s Law states that

The heat change of a reaction depends on the initial and final states of the reaction and is independent of the route by which the reaction may occur

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In fractional distillation, naphtha is what (a) fraction (b) boiling range (c) carbon atoms per molecule (d) uses

(a) 3 (b) 350-435 K (c) 8-10 (d) petrol and organic chemicals

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In fractional distillation, gas oil is what (a) fraction (b) boiling range (c) carbon atoms per molecule (d) uses

(a) 5 (b) 525-625 K (c) 14-19 (d) diesel fuel

In fractional distillation, refinery gas is what (a) fraction (b) boiling range (c) carbon atoms per molecule (d) uses

(a) 1 (b) <300k (c) 1-4 (d) LPG

In fractional distillation, fuel oil and residue is what (a) fraction (b) boiling range (c) carbon atoms per molecule (d) uses

(a) 6 (b) >625 K (c) >19 (d) bitumen, lubricating oil

In fractional distillation, kerosene is what (a) fraction (b) boiling range (c) carbon atoms per molecule (d) uses

(a) 4 (b) 435-525 K (c) 10-14 (d) jet fuel

Mercaptans

Very smelly organic sulfur compounds are added to gas (natural gas and LPG) to give it a smell

Auto-ignition

Is ignition in an internal combustion engine before a spark is produced

The octane number is

A measure of the tendency of a fuel to cause knocking

What octane rating do heptane (C7H16) and 2,2,4-trimethylpentane have?

0 and 100

What are additives and give examples?

Are used to prevent knocking in petrol e.g lead and oxygenates (MTBE)

1). Disadvantages of lead 2). Advantages of oxygenates

1). Release toxic fumes and are catalytic poisons 2). Produce lower levels of carbon monoxide when they burn

Isomerisation

When certain compounds are heated in the presence of a catalyst, a different structural isomer is formed

Dehydrocyclisation

Involves the formation of a ring compound, accompanied by the removal of hydrogen gas

Catalytic Cracking

Involves taking a heavy oil e.g kerosene and hearing it to a high temperature in the presence of a catalyst. The large molecule breaks down into several smaller ones

Properties of chloroalkanes

One/more hydrogens replaced with chlorine. Functional group alkyl. e.g CCl4 tetrachloromethane. Non-polar. Used as solvents.

Properties of alcohols

Bond OH (hydroxyl) is the functional group. An OH with a carbon bonded to one other carbon is a primary alcohol, if the carbon is bonded to two other carbons it's a secondary carbon. Has hydrogen bonding therefore energy required to break these bonds is high which raises the boiling point . Uses: alcohol fermentation and solvents

What are the shape of chloroalkanes? Give examples

Tetrahedral e.g alkanes, chloroalkanes, and alcohols

What shape are unsaturated molecules? Give examples

Planar e.g alkenes, aldehydes, ketones, carboxylic acids, esters, aromatic compounds

Properties of aldehydes

Carbonyl group is the functional group (c=o) only at end of molecule. Very polar, dipole-dipole interactions, higher boiling points. Lower aldehydes are soluble in water because of the C=O, others soluble in cyclohexane/ methylbenzene. E.g benzaldehyde almond flavouring.

Ketones

Have carbonyl group in middle of molecule. Must have at least three carbons present. E.g propanone nail varnish remover

Properties of carboxylic acids

Carboxyl group is the functional group (C=O-OH). Hyrdrogen bonding therefore lower molecules soluble in water. E.g ethanoic acid vinegar, methanoic acid nettles

Properties of esters

Made up of alcohol and a carboxylic acid. Natural fruity smells. Fats and oils. Ethyl ethanoate is used as a solvent paint

Organic natural products

Any chemical produced in nature by plants or animals e.g paracetamol, aspirin

Steam distillation

The process by which a liquid immiscible with water, is mixed with water and the two vapour pressures reach atmospheric pressure and the mixture will distil. This must happen below the boiling point of the water

Saponification

The common name for the base hydrolysis of esters

What is hydrolysis?

The chemical decomposition of a substance by water, the water itself also being decomposed

Evidence for the bromine mechanism

When NaCl is added to the mixture. 2-bromoethanol 1-bromo-2-chloroethane and 12-dibromoethane is formed

Hydrolysis

The chemical decomposition of a substance by water, the water itself being decomposed