Organic Flashcards

0
Q

Formation of ethanoic acid impurities

A

Water, ethanal and ethyl ethanoate

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1
Q

Reflux distillation

A

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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2
Q

Mass=

A

Volume x density

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3
Q

Moles=

A

Mass / molar mass

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4
Q

A homologous series

A

A family of compounds with the same general formula

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5
Q

Structural Isomers

A

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

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6
Q

Impurities present in ethyne gas

A

Hydrogen sulfide and phosphine

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7
Q

An exothermic reaction

A

Gives out heat to surroundings

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8
Q

An endothermic reaction

A

Takes in heat from surroundings

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9
Q

The heat of reaction of a chemical reaction

A

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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10
Q

Bond Energy

A

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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11
Q

The heat of combustion of a substance

A

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

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12
Q

The kilogram calorific value

A

Is defined as the heat energy produced per kilogram of fuel

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13
Q

The heat of formation

A

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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14
Q

The law of conservation of energy states that…

A

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

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15
Q

Hess’s Law states that

A

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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16
Q

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

A

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

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17
Q

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

A

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

18
Q

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

A

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

19
Q

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

A

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

20
Q

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

A

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

21
Q

Mercaptans

A

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

22
Q

Auto-ignition

A

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

23
Q

The octane number is

A

A measure of the tendency of a fuel to cause knocking

24
Q

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

A

0 and 100

25
Q

What are additives and give examples?

A

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

26
Q

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

A

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

27
Q

Isomerisation

A

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

28
Q

Dehydrocyclisation

A

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

29
Q

Catalytic Cracking

A

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

30
Q

Properties of chloroalkanes

A

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

31
Q

Properties of alcohols

A

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

34
Q

What are the shape of chloroalkanes? Give examples

A

Tetrahedral e.g alkanes, chloroalkanes, and alcohols

35
Q

What shape are unsaturated molecules? Give examples

A

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

36
Q

Properties of aldehydes

A

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.

37
Q

Ketones

A

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

38
Q

Properties of carboxylic acids

A

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

39
Q

Properties of esters

A

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

40
Q

Organic natural products

A

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

41
Q

Steam distillation

A

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

42
Q

Saponification

A

The common name for the base hydrolysis of esters

43
Q

What is hydrolysis?

A

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

44
Q

Evidence for the bromine mechanism

A

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

45
Q

Hydrolysis

A

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