cExtra Flashcards

(99 cards)

1
Q

Core practical 1

A

Investigate change in pH on adding powdered calcium hydroxide or oxide to a fixed volume of HCL

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2
Q

Method of core practical 1

A

Put a piece of universal indicator paper onto the white tile.
• Dip the end of the glass rod into the liquid, then tap it onto the
universal indicator paper.
• Wait 30 seconds, then match the colour to the appropriate pH on the
pH colour chart.
• Rinse the glass rod with water.
C Measure out 0.3 g of calcium hydroxide powder onto a piece of paper
or a ‘weighing boat’.
D Add the calcium hydroxide powder to the beaker, stir, then estimate
and record the pH of the mixture.
E Repeat step D seven times so that you add a total of 2.4 g of calcium
hydroxide powder to the acid.

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3
Q

Core practical 1 results

A

The pH increases rapidly at the neutralisation point

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4
Q

Core practical 1, what is calcium hydroxide?

A
Calcium hydroxide is a
base. Bases can be
used to neutralise
acids according to the
following reaction:
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5
Q

Core practical 1-what would that graph look like

A
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6
Q

Core practical 2

A

Electrolysis of copper sulphate with copper electrodes

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7
Q

Core practical 2, what is the method

A

them with emery paper. Label on of the electrodes as ‘anode’
the other as ‘cathode’
B Measure and record the mass of each electrode
C Half fill a beaker with copper sulphate solution
D Set up the circuit as shown in the diagram
Method 1 : Using copper electrodes

E Turn the power on and adjust the variable resistor to give a current
of 0.2A. Record the current. Leave the power on for 20 minutes,
adjusting the variable resistor to keep the current constant.
F Turn off the power and remove the electrodes from the beaker.
G Gently rinse the electrodes with distilled water and then dip them in
some propanone. Remove the electrodes from the propanone and
gently shake them to dry.
H Measure and record the mass of the dry electrodes
I Repeat the experiment using currents of 0.3A, 0.4A and 0.5A

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8
Q

Core practical 2 reaction at the anode

A

Cu → Cu2+ + 2e-

which is Oxidation

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9
Q

Core practical 2 reaction at the cathode

A

At the cathode: Cu2+ + 2e- → Cu which is Reduction

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10
Q

Core practical 2 explantation

A

Using copper electrodes copper is removed
from the anode and deposited on the
cathode. The mass of the anode will
decrease and the mass of the cathode will
increase.
The amount of copper transferred is proportional to the charge (the number of
electrons). This is determined by the current (I) and the time (t) for the electrolysis.

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11
Q

Core practical 2 graph

A
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12
Q

Core practical 2 diagram

A
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13
Q

What is core practical 3?

A

Investigating the electrolysis of copper sulphate using carbon electrodes

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14
Q

What is the method for core practical 3

A

A Set up the circuit as shown in the diagram opposite
B Turn on the power
C Record your observations and the name of the
product formed at each electrode.

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15
Q

Core practical 3 what would happen at the anode

A

Bubble of colourless gas, product is oxygen

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16
Q

Rule for competition at cathode

A

Least reactive metal will form

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17
Q

Rule for competition at anode

A

Halides>hydroxide>all other negative ions as the simplest non metal will form

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18
Q

Giant covalent

A

High melting point, insoluble in water and most do not conduct electricity apart from carbon as graphite

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19
Q

What is molecular formula

A

The number of atoms of each element bonded together in a simple molecule.

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20
Q

Explain simple molecular(covalent).

A

Low melting/boiling points, a few and soluble and most do not conduct electricity

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21
Q

What are some of the properties of ionic compounds

A

Form crystals due to their iregular shape

Have high melting and boiling points as the strong electrostatic forces require great deal of heat energy to break

Cannot conduct electricity when solid as the ions cannot move so they are locked in place

Can conduct electricity when they melted or dissolved in water(to give solutions)as the ions can now move and carry the charges.

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22
Q

What is the test for carbon dioxide?

A

Carbon dioxide turns limewater milky. A lighted wooden splint goes out in a test tube of carbon dioxide but this happens with other gases, too. So the limewater test is a better choice.

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23
Q

Litmus in alkaline

A

Blue

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24
Q

Litmus in acid

A

Red

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25
Methyl orange in alkaline
Yellow
26
Methyl orange in acid
Red
27
pHENOLPHLALEIN IN ALKALINE
pink
28
Phenolplhalein in acidic
Colourless
29
What is the stoichiometry of the reaction?
The ratio of moles of each substance.
30
What are some of the chemical properties of transition metals?
They form coloured compounds. Often used as catalysts
31
How is copper purified using electrolysis?
Copper electrodes can be used. The copper atoms in the anode lose electrons to become copper ions. These dissolve in the solution and migrate to the cathode where they are deposited as pure copper. Inpurities from the anode do not form ions and collect below the anode as a 'sludge'.
32
ad of bioleeeching
Does not require high temp
33
Add of phyto
Can extract metals from contaminated soils
34
Dis of bioleeching
Toxic substances and sulfuric acid can be produced by the process and damage the environment
35
Dis of phytoextraction
More expensive than mining some ores growing plants is weather dependant
36
hat is a tarnish and how can it stop corrosion?
Metals such as aluminium are quite reactive and would be expected to corrode quickly. However, they do not corrode bewcause their surfaces form a protective layer(a tarnish)which prevents further reaciton.
37
What are the advantages of recycling?
Nautral reservers of metal ores will last longer. The need to mine ores is reduced. Mining can damage the landscape as well as create noise and dust pollution. Less pollution may be produced. For example, sulfur dioxide is formed when some metals are extracted from metal sulfide ores. Less waste metal ends up in landfill sites. Many metals need less energy to recycle them than to extract new metal from the ore.
38
What are some of the disadvantages of recycling?
Costs and energy used can be extremely high.
39
What is bioleeching? It is for copper.
Uses bacteria grown on a low grade or and the bacteria produce a solution containing copper ions called a leachate.. Copper is extracted from the leachate by displacement using scrap iron then purified by electrolysis. This method can also be used for metals such as nickel, cobalt and zinc.
40
Hbaer process equation
N2+3H2 ⇌ 2NH3
41
For aluminium what is negative electrode
Think the box is lined with
42
Where does molten aluminium leave
At a small hole at the bottom
43
What are the conditions for the haber process
450C, 200 atmoshperes of pressure and the use of an iron catalyst.
44
What factors are taken into account when choosing a reaction pathway?
Availability and cost of raw materials, the rate of reaction and equilibrium position and atom economy and yield and usefulness of by-products.
45
atom economy bottom
All reactants
46
How is the energy transferred in chemical cells?
Mainly electricity but a bit of heating.
47
What does avogrado's law state?
If the temperature and pressure are the same. equal volumes of different gases contain an equal number of molecules.
48
What are the strengths and weaknesses of fuel cells
They do not produce carbon dioxide, however most hydrogen is manufactured by the reaction of steam with coal or natural gas which releases carbon dioxide as a by-product. Very hard tp stpre hydrogen and can be dangerous if released(simple and light so hard to store).
49
What do fertilisers do?
Replace the mineral ions needed by plants and so promote plant growth.
50
What are sodium, potassium and ammonium salts?
Soluble.
51
Are nitrates insoluble?
No.
52
What are chlorides?
Mostly soluble apart from silver and lead.
53
What are Sulfates?
Mostly soluble apart from lead, barium and calcium.
54
What are carbonates?
Mostly insoluble apart from sodium, potassium and ammonium.
55
What are hydroxides?
Mostly insoluble apart from sodium potassium and ammonium.
56
Why might the theoretical yield not be met?
Other side reactions may occur, product/reactant lost or reaction may not be complete.
57
Where is anode
LEFT
58
Where is cathode
RIGHT
59
Where is hydrogen?
left
60
Where is oxygen
Right
61
What are the electrodes made of?
Porous carbon
62
Where does water leave?
Outlet of cathode compartment, not inlet.
63
What happens when the hydrogeN enters?
The hydrogen is oxidised into ions.
64
What happens after the hydrogen enters?
The lost electrons pass around the wire to the cathode while the hydrogen ions move through electrolyte.
65
What is the electrolyte?
Potassium hydroxide.
66
What happens when the oxygen comes in from the other inlet?
The oxygen, hydrogen ions and electrons combine to make water. There is a spare oxygen atom so we need two sets for each oxygen molecule.
67
Reaction at cathode?
02+4H++4E-=2H20
68
Hydrogen entering.
H2=2H++2E-.
69
Overall equation.
02+2H2=2H20.
70
Where does the electrical energy come from?
Movement of electrons through the wire at the top.
71
Another advantage?
Less pollution and produce less waste.
72
Idea of chemical cells?
If we take two different metals and place them in an electrolyte then we can produce electricity.
73
3 acids.
HCL H2SO4 HNO3
74
3 acids words
Chloride sulphate and nitrates.
75
What do liquids have?
No fixed arrangement.
76
Transfer gas.
Use a gas syringe and delivery tube.
77
Bong
bung
78
How massive is 1 hydrogen atom?
1/avogadro.
79
What do you remmber to do to the conical falsk in titration?
Swirl the conical flask to make sure all of the mixture has reacted.
80
Pneumonic for all diatomic
Have no fear of ice cold beer.
81
What are halides?
Top four of group 7.
82
End point of methyl orange
Orange
83
What is the thing that drops the liquid in called in a titration
A burette
84
Lab scale
Small
85
indus scale
large
86
lab starting materials
Ammonia solution and dilute sulfuric acid
87
indust starting materials
Raw materials
88
Lab stages
Titration and then crystalisation
89
Indust stages
Several stages
90
Lab type
batch
91
indust type
Continuous
92
Where do you place crystals at the end
In an oven to dry them
93
Evaluate the advantages and disadvantages of providing electrical energy in a spacecraft using hydrogen-oxygen fuel cells rather than chemical cell
advantages • once set up, fuel cells require no maintenance • chemical cells will need to be replaced / chemical cells have a limited lifetime • fuel cells operate as long as reactants are supplied • voltage drops in chemical cells as reactants are used up • once used chemical cells cannot be used again or need recharging • used chemical cells take up valuable space on spacecraft • new chemical cells need to be transported to spacecraft • used chemical cells need to be transported back to earth • water produced in the fuel cell is the only product • water can be used on the spacecraft as drinking water disadvantages • hydrogen and oxygen must be supplied • gas tanks need to transported by spacecraft • storage of hydrogen is difficult because it is a gas • hydrogen is flammable • fuel cells are expensive to manufacture
94
Characteristic of fertilisers
Soluble
95
Similariti of indus and lab
both use sulfuric acid
96
Why does alumiinium have to be extracted by eelctorlyis
More reactive than carbon so cannot be replaced by carbon
97
Condenser to
Increase effectiveness of cooling to ensure more water vapour condenses
98
add drops
1 at a time
99
competition at anode
If the negative ion from the ionic compound is simple (eg Cl- or Br-), then that element is produced. If the negative ion is a complex ion (eg NO3-, SO42-, CO32-), then oxygen is produced from the hydroxide ion present instead.