Chemistry Flashcards
(125 cards)
1
Q
What is a Homologous series
A
a group or organic molecules with the same functional group
2
Q
what is a cycloalkene, (draw a diagram as well)
A
When alkenes are connected in a circle
Google for diagrams
3
Q
What is a isomer?
A
When a element has the same molecular formula but have a different electron arrangement
4
Q
What happens when a hydrocarbon increases? (4)
A
- there is a larger surface area
- a higher amount of intermolecular forces
- a higher amount of energy is required to break these bonds
- this results in higher melting/ boiling point
5
Q
Draw 2 structural isomers for C6H14
A
/\/\/ or /
/\/
/
If confused look on google
6
Q
A sigma bond happens in alkanes
Draw a sigma bond
A
Google it
7
Q
Where can a sigma bond only happen?
A
On the “x” axis
8
Q
A Pi bond ONLY happens in alkenes, draw a Pi bond
A
Google it
9
Q
What is a geometric isomer?
A
Same structural formula but a different arrangement in space
10
Q
What are the three types of geometric isomers?
A
- Symmetric and Asymmetric
- Cis and Trans
- Z and E isomers
11
Q
Draw a symmetric isomer for Ethene?
A
google it
12
Q
Draw a asymmetric isomer for Ethene?
A
google it
13
Q
What is a Cis isomer?
A
When there are matching groups on the same side
-Makes a C shape`
14
Q
What is a trans isomer?
A
When the matching group are on opposite sides of the double bond
15
Q
What is a “Z” isomer?
A
like cis isomer, matching groups on the same side
16
Q
What is a “E” isomer?
A
like trans isomer, groups on different sides
17
Q
What is a halo-alkanes?
A
when a halogen is attached to an alkane
18
Q
Draw the electrophilic addition of Bromine?
A
google it
19
Q
What are the most useful types of hydrocarbons?
A
Short chain hydrocarbons
20
Q
What are 2 uses for short chain hydrocarbons?
A
- fuel
- making polymers
21
Q
What is the process called for breaking hydrocarbons?
A
cracking
22
Q
What are the two methods for cracking called?
A
Catalytic cracking
Steam cracking
23
Q
What is catalytic cracking process?
A
uses a temperature of approx 550c
uses a catalyst known as Zeolite which contains aluminium oxide and silicon oxide
24
Q
What is the steam cracking process?
A
uses a high temperature of over 800c and no catalyst just steam
25
what is combustion important for ?
- transport
- electricity
- heating
26
What is the equation for combustion?
hydrocarbon + oxygen ---> water + carbon dioxide
27
When and why are free radicals formed?
- because alkanes need a very reactive thing to break their covalent bonds
- they are formed when a covalent bond splits to return the electrons to their atoms
28
What is homolytic fission?
when a bond splits and creates a free radical
electrons move individually
needs uv or high temperature
29
Heterolytic fission?
creates a positive and negative bond
| splits a bond
30
what are the 3 stages for a free radical mechanism?
initiation
propagation
termination
31
Describe the initiation phase in free radical mechanism?
| give example with chlorine
the free radical is formed
(needs uv or 300c)
Cl2--> 2Cl.
32
Describe the propagation in free radical mechanism?
| give example with chlorine
step that starts and end with a free radical
the product starts to be formed
CH4+Cl.---> .CH3+HCl
33
Describe the termination phase in a free radical mechanism?
| give example with chlorine
steps in which two free radicals react
there are no radicals in the products
2Cl.---> Cl2
34
Draw a dash and wedge diagram for methene
google it
35
What is the bond angle for a tetrahedral shape?
109.5 degrees
36
What is the bond angle for a trigonal planar shape?
120. degrees
37
What is the bond angle for a linear shape?
180 degrees
38
Describe the bond length and strength for a sigma bond?
strong, good overlap of orbitals
39
Describe the bond length and strength for a Pi bond?
weaker, less overlaps of orbitals
40
describe the bond length and strength for an alkane?
single bond = sigma bond so weaker and longer
41
Describe the bond length and strength for an alkene?
double bond= Sigma and Pi bond so it is stronger
42
Describe a Benzene bond?
fits between single and double bonds
| sigma + 0.5 Pi between each carbone
43
What are the properties of alumina?
```
Ionic
Hard- strong bonds, lots of energy
High melting Point
insulator when solid
conductor when liquid
```
44
When an acid dissolves in water what ion does it produce?
H+ ions
45
When an alkali dissolves in water what ion does it produce?
OH- ions
46
Acid is a ? donor ?
proton (H+)
47
Base is a ? acceptor?
H+ acceptor
48
Acid is a ? acceptor?
OH- acceptor
49
is hydrochloric acid a acid/alkali/base?
acid
50
is sodium hydroxide a acid/alkali/base or alkali and base?
alkali and base
51
Is sulfuric acid an acid/ base/ alkali?
acid
52
Is magnesium oxide an acid/ alkali/ base?
base
53
Is nitric acid an acid/ alkali/ base?
acid
54
Is copper hydroxide an alkali/ acid/ base or alkali and base
alkali and base
55
Bases ? acid in water?
Neutralise
56
Define amphoteric?
when a compound behaves as an acid + base
57
Why can alumni be amphoteric?
because it can act as a base accepting protons and also a alkali accepting hydroxide ions
58
What happens at the cathode in electrolysis?
H2 is produced
Positive ions are produced
2H( positive) + 2e- (negative) ----> H2
59
What happens the anode?
negative ions
Oxygen is produced
4OH ---> 4e- + O2 + 2H2O
60
What is the overall equation for electrolysis?
2H2O----> 2H2 + O2
61
In aqueous solutions what happens at the anode?
- Non metals are formed
- If a halide is present the halogen is formed
e. g 2Cl----> Cl2 + 2e -
- If not Oxygen is formed
62
In electrolysis how do you decide what is formed at the anode?
step by step
1) what is the negative ion
2) is it aqueous
a) yes- is it a halogen
i) yes-halogen is produced
ii) no- oxygen is produced
b) no- the element is produced from the ion
63
In electrolysis how do you decide what is formed at the cathode?
step by step
1) what is the positive ion
2) is it aqueous
a) yes - is it more reactive than hydrogen
i) yes- hydrogen is produced
ii) no- the metal is produced as an element
b) no- the element is produced from the ion
64
what is a steroisemer?
the same structurals formula but different arrangement of atoms in space
65
What is Brine?
Sodium chloride solution
66
Metals are always ? Ions
positive
67
Non metals are always ? negative ions
negative
68
What does PANIC stand for?
```
Positive
Anode
Negative
In
Cathode
```
69
Electrolysis of Brine:
| In the No Barrier Cell what is formed at the Cathode?
- sodium hydroxide
| - Hydrogen gas
70
Electrolysis of Brine:
| In the No Barrier Cell what is formed at the Anode?
-Chlorine gas
71
What is sodium hydroxide used for?
- cleaning product
- removing pollutants from water
- manufacture of paper
72
What is Chlorine used for?
- disinfectant
| - making plastics
73
What is Hydrogen used for?
- manufacture of hydrochloric acid
| - potential as a pollution free fuel
74
what is enthalpy change?
the amount of energy per substance
75
what enters the membrane cell in the anode and cathode?
```
anode = concentrated sodium chloride solution
cathode = water
```
76
What exits the membrane cell in the anode and cathode?
```
anode = sodium chloride solution
cathode = sodium hydroxide solution
```
77
What is the equation for enthalpy change?
enthalpy change = enthalpy of products - enthalpy of reactions
78
What is the role of a catalyst?
they affect rates of reactions
lowers activation energy
increases the number of successful collisions
increases the rate of reaction
79
What is the definition of standard enthalpy change of hydration?
energy released when one mole of ions dissolves in water
80
What is the definition of standard enthalpy change of formation?
When one mole of a compound is formed from elements under standard conditions
81
What is the definition of standard enthalpy change of combustion?
When one mole of an element/ compound reacts with oxygen under standard condition
82
What is a membrane cell made up of?
Polymers
83
What can only pass through the membrane cell?
positive ions
| H+ ions and Na+ ions
84
What ion cannot pass through the membrane cell?
Cl- ions
85
In the membrane cell what is formed at the cathode?
sodium hydroxide
86
What is the diaphragm cell made up of?
asbestos and polymers
87
Why is the level of brine solution higher at the cathode in the diaphragm cell?
so that electrolyte does not flow back
88
In the diaphragm cell, what enters through the anode?
sodium chloride
89
In the diaphragm cell, what is produced at the cathode?
sodium hydroxide
90
When the solution is produced it becomes contaminated, what does that mean?
it is no longer 100% pure with sodium chloride
91
`Is a base a solid or a soluble base?
solid
92
Is an alkali a solid or a soluble base?
soluble base
93
What is the equation for enthalpy change of combustion?
CH4+ O2----> CO2+ H2O
94
When balancing combustion equations what is the only part that cannot be changed?
CH4
95
What are the steps for calculating enthalpy change experimentally
```
1) measure energy transfer
energy transferred x SHC x Temp
2) calculate the number of moles of substance
moles= mass/Mr
3)Calculate enthalpy change
= - (energy transferred/ moles)
```
96
What is the definition for Hess's law
the method for calculating enthalpy change theoretically
97
Draw Hess's law diagram for combustion
google it
98
In Hess law which way do the arrows go for:
a) combustion
b) formation
a) down
| b) up
99
What are the steps for Hess's law
```
1) work out which ways arros go
(formation or combustion)
2)Write in information on arrows
3) work out what goes at the bottom
4) construct equation
```
100
What does the Hall-Heroult process do?
extracts allumnia
101
why is alumina dissolved in cryolite in the Hall-Heroult process?
because it lowers the melting point
102
What is the Bayer process?
Extracting Al2O3
103
What are the stages for Bayer process?
1) bauxite is crushed to make grains
2) bauxite is reacted with sodium hydroxide (to remove impurities)
3) iron oxide and titanium oxide are removed by filtration
4) solution crystallizes to form Al (OH3)
5) heat the Al (OH3) to convert it to alumina (Al2O3)
104
What is the definition of a transition metal?
when it forms one or more stable ions which have incompletely filled orbitals
105
What are the characteristics for transition metals?
incomplete d subshell
variable oxidation states
complex ion formation
106
What are the properties of transition metals?
Catalysis
| coloured compounds
107
What is a complex ion?
positively charged ion surrounded by a number of molecules that are oppositely charged
108
What is a ligand?
a molecule with a lone pair of electrons
109
What is a dative bond?
When both electrons are donated by one molecule to form a covalent bond
110
Why are transition metals easy to form complex metals?
because they are small with a high charge to size ratio
111
Homogeneous catalyst what is the reactants and catalysts like in phase?
it can be in one or more oxidation state
112
Heterogeneous catalyst what is the reactants and catalysts like in phase?
the catalyst is in a different phase than reactants therefore it can not mix with the reactants
113
Why are transition metals great catalysts?
- they can have variable oxidation states
- they can be oxidised and reduced
- they lower the activation energy by providing an alternative route
114
What are the steps for the contact process?
1) sulfur dioxide is made
2) sulfur trioxide is made
3) sulfur trioxide is converted into sulphuric acid
115
In the contact process what is the role of vanadium?
to act as a catalyst as it can change its oxidation state
116
What does the Haber process do?
makes ammonia
117
What are the steps for the Kroll process?
1) coke ( a form of carbon), and chlorine are heated together at 900c to form titanium chloride
2) magnesium is used as a reducing agent to form titanium
118
What is the role of a reducing agent?
gives electrons to another element.
119
What is a batch process?
When the products come out in groups and not continuously
120
What is a continuous process?
the product comes out without interruption and not in groups
121
Draw a no barrier cell in the electrolysis of brine?
google it
122
Draw a membrane cell in the electrolysis of brine?
google it
123
Draw an endothermic reaction
google it
124
Draw and exothermic reaction
google it
125
Draw a diagphragm cell in the electrolysis of brine
google it
