Higher Flashcards

1
Q

What is a reducing agent?

A

A substance that causes another substance to gain electrons causes the O:H ratio to decrease in a molecule is oxidised

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2
Q

What is an oxidisng agent?

A

A substance that causes another substance to lose electrons causes the O:H ratio to increase in a molecule is reduced

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3
Q

Electronegativity

A

The attraction an atom has for a shared pair of electrons

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4
Q

Oxidation

A

Loss of electrons Increase in O:H ratio Loss of hydrogen Gain of oxygen

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5
Q

Reduction

A

Gain of electrons Decrease in O:H ratio Gain of hydrogen Loss of oxygen

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6
Q

Free radical

A

A species (atom, ion, molecule) with an unpaired electrons

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7
Q

Soap

A

Sodium salt of a fatty acid

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8
Q

Fatty acid

A

A long chain carboxylic acid

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9
Q

Hydrolysis

A

The breaking apart of a molecule using the chemical action of water

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10
Q

Raw material

A

A substance that is easily obtained from environment

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11
Q

Feedstock

A

A substance that is used to manufacture new substances

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12
Q

Enthalpy of combustion

A

The energy released when 1 mole of a substance completely combusts

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13
Q

Dynamic equilibrium

A

The point in a reversible reaction when the forward and reverse rates of reaction are equal the concentrations of reactants and products are constant

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14
Q

Le Chatelier’s Principle

A

If a change is imposed upon a system at equilibrium the position of equilibrium will adjust to minimise the effects of the change

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15
Q

Amino acid

A

A substance that contains both the amino group and carboxylic group

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16
Q

Essential amino acid

A

An amino acid that can’t be synthesised by the body needs to be taken in through the diet

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17
Q

Electrostatic attraction

A

An attraction between oppositely charged particles

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18
Q

Enthalpy change

A

The net difference between the enthalpy values of reactants and products

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19
Q

Initiation

A

The first step of free radical chain reaction when a molecule is split into 2 free radicals

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20
Q

Propogation

A

2 step 2nd stage of free radical change reaction when free radical is propogated

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21
Q

Termination

A

The 3rd step of free radical chain reaction when 2 free radicals collide and form covalent bond

22
Q

Metallic bond

A

The attraction between the nucleus of metals and the delocalised outer electrons

23
Q

What is the bonding continuum?

A

Using the electronegativity (EN) difference between 2 atoms to predict what type of bond they will form

24
Q

How is ionic character linked to electronegativity?

A

The greater the difefrence in electronegativity values between 2 atoms tyhe higher the ionic character will be.

25
At dynamic equilibrium, how do we describe the concentrations of reactants and products?
They are ***_CONSTANT_***
26
At dynamic equilibrium, how do we describe the rates of the forward and reverse reactions?
They are ***_EQUAL_***
27
What 3 changes can affect the position of equlibrium if they are imposed upon a system at equlibrium?
Change in temperature Change in pressure Change in concentration
28
What can be added to edible oils to make emulsifiers?
Glycerol
29
Show a hydrogen bond between 2 water molecules
30
Whic 3 atoms if directly bonded to a H atom will result in hydrogen bonding? What properties do these atoms have that lead to this?
**N O F** They are small atoms with high electronegativity values
31
Which 2 *_compounds_* at Higher Chemistry have covalent networks?
Silicon dioxide and Silicon carbide
32
Which 3 elements have covalent network structures?
Carbon Silicon Boron
33
Explain the properties of graphite based on its structure
Each C atom in the layer only uses 3 of its valence electrons in covalent bonding so the layer has delocalised electrons. The weak LDF forces are relatively easiluy broken so the layers can be separated from one another making it useful as a lubricant and in pencils
34
What 2 conditions must be met before collisions can be successful?
Collisions must happen with energy equal to or greater than the activation energy and the geometry has to be correct.
35
Place the van der Waals (intermolecular) attractions in order of decreasing strength
1. Hyrogen bonding 2. Polar -Polar (permanent- permanent dipole) 3. London Dispersion Forces
36
Energy distribution diagram
37
Why is de-ionised water used to make standard solutions?
To minimise the possibility of ions in the water leading to unwanted side reactions and salt formation which could alter the concentration of the solution
38
Explain how electron wobble sets up a teemporary dipole
Electron cloud wobbles. Centre of negative charge moves One side becomes slightly positive and the other slightly negative
39
Explain how an induced dipole is et up
The dipole of one atom or molecule affects the electron cloud on another. The resulting electrostatic attractions between these dipoles are called London Dispersion Forces
40
Explain the effect ehat elongating a C chain has on the melting and boiling points
The increasing number of electrons lead to increased LDF attractions
41
Relative strength of dipole attractions?
42
Explain why ice is less dense than water relating to its structure
43
Relative polarities of various Carbon compounds
44
Whys is the 2nd ionisation energy of Na so much higher than the 1st?
1. Removing from a stable full shell 2. Less shieding effect from nuclear charge 3. Electron lies much closer to nuclear charge
45
Where does electronegativity pop up in Higher course?
1. Giving a definition of it. 2. Giving trends in table 3. Using values to compare covalent or ionic character 4. Predicting the polarity of a covalent bond
46
Which alcohol is obtained upon hydrolysis of a fat or oil?
Glycerol Propan-1,2,3- triol
47
How could the levels of unsaturation in oils / fats be tested?
Bromine (or Iodine) will add across the C=C bond and decolourise as it does so. A clear end point will be shown when the decolourising stops. The more C=C bonds there are, the higher the volume of Br2 or I2 it will take to reach end point
48
The enthalpy of cumbustion of ethanol is given as -1367 kJ mol-1 Give a reason the value obtained through bond enthalpy method will be different from this
Some of the bond enthalpy values used to calculate this will be ***mean*** bond enthalpies
49
Why are some bond enthalpy values ( O-H for example) given as mean bond enthalpies?
Because these bonds are found in different compounds and will have different values in each. The value shown is the mean of these different values.
50
Why is CO2 a non-polar molecule?
51
What is "Enthalpy"
The amount of potential energy in a system