Principles Of Chemistry Flashcards

(66 cards)

1
Q

Describe the experiment involving the diffusion of Potassium Manganate (V||) and water

A
  1. Take a beaker of water and place some potassium Manganate (V||) at the bottom.
  2. The purple colour slowly spread out to fill the beaker, diffusing out among the particles of water
    3.
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2
Q

Symbol formula for Ammonia

A

NH3

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3
Q

Symbol formula for Ammonium.’

A

NH4

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4
Q

What does aqueous ammonia give off?

A

Ammonia gas

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5
Q

What does Hydrochloric acid give off?

A

Hydrogen Chloride gas

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6
Q

Describe the experiment involving ammonia and Hydrogen Chloride.

A
  1. Get a tube and on either end put a cotton wool and soak them in Hydrochloric acid one one and aqueous ammonia on the other.
  2. NH3 gas diffuses at one end of the tube and the HCL diffuses from the other. When they meet they react to form ammonium chloride.
  3. You’ll get a white ring of ammonium chloride forming in the glass tube.
  4. Ring is formed closer to where the HCl was because the particles of ammonia are smaller and lighter than the particles of hydrogen chlorid, so they diffuse though the air more quickly.
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7
Q

What colour is bromine gas?

A

Brown

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8
Q

Describe how you can use bromine gas and air to demonstrate diffusion in particles.

A
  1. Fill a gas jar full of bromine gas, and the other half full of air - separate the gases with a glass plate.
  2. When you remove the glass plate, you’ll see the brown bromine gas slowly diffusing through the air.
    3 the random motion of the particles means that the bromine gas will eventually diffuses through the air
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9
Q

Relative mass and charge of Proton, neutron and electron?

A

PARTICLE. RELATIVE MASS. RELATIVE CHARGE
Proton. 1. +1
Neutron. 1. 0
Electron. 1/2000. -1

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10
Q

Describe an Element, a Compound and Mixture.

A

Elements consist of one Type of Atom only
Compounds are chemically bonded and are hard to break this bond. The properties are not the same as the elements themselves.
A mixture can be easily separated and are not chemically bonded. Can be separated methods such as distillation. Properties are the same as the separate apart.

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11
Q

The colour of Sulphur?

A

Yellow

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12
Q

When is Filtration used and describe the experiment.

A

To separate insoluble solid from a liquid.
1. Get a beaker and a cone shape shaped beaker and fold the filter paper into a cone shape and the liquid will go through the filter paper into the beaker and the solid will be left in the filter paper.

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13
Q

What a good experiment to show diffusion?

A

Potassium Maganate (V||) and Water

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14
Q

What is Crystallisation used for and describe the experiment for it.

A

Separate a soluble solid from a solution.
1. Pour the solution into an evaporating dish.
2. Slowly heat the solution. Some of the solvent il evaporate and the solution will get more concentrated. Stop heating when’d eyestalks form.
3. Remove the dish from the hat and leave it in a warm place for the rest of the solvent to slowly evaporate - this way you get nice big
crystals
4. Dry the product either by using a drying oven or a desiccator for this (a desiccator contains chemicals that remover water from the surroundings)

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15
Q

How can you separate rock salt?

A

By filtration and Crystallisation.
Rock salt is a mixture of salt and sand
Salt and Sand are both compounds - but salt dissolves in water and sand doesn’t. This vital difference in their physical properties gives a great way to separate them.
1. Grinding; grind up the rock salt with a pestle and mortar.’
2. Dissolving p; dissolve in beaker and stir
3. Filtering; filter through filter paper in a funnel
4. Evaporate in an evaporating dish
The sand doesn’t dissolve (it’s insoluble) so it stays as grains in the filter paper.
The salt is dissolved in solution so it goes through the filter paper and the water is evaporated and the salt forms crystals

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16
Q

What are Molecules and how are they held together?

A

Groups of atoms

Held together by covalent bonds

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16
Q

What is the mass number?

A

Total of protons and neutrons

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16
Q

What is the Atomic number?

A

Number of protons which is also number the number of electrons

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17
Q

What are the properties of a compound?

A

The properties of a compound are often totally different from the properties of the original elements

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18
Q

What are the properties of a mixture?

A

The properties of a mixture are just a mixture of the properties of the separate parts

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19
Q

Describe Chromatography.

A
  1. Draw a line near the bottom of a sheet of filter paper
  2. Add spots of different dyes to the line at regular intervals
  3. Loosely roll the sheet up and out it in a beaker of solvent e.g water
  4. The solvent used depends on what’s being tested. Some compounds dissolve well in water, but sometimes other solvents like ethanol are needed
  5. Make sure dyes aren’t touching the solvent - you don’t want them to dissolve into it
  6. Place a lid on top of the container to stop the solvent evaporating
  7. The solvent seeps up the paper, carrying the dyes with it
  8. Each different dye will move up the paper at a different rate and form a spot in a different place
  9. The end result is a pattern of spots called a chromatogram
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20
Q

What does the distance of the dyes in chromatography depend on?

A

Solvent and the paper you use

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21
Q

Explain how Chromatography can help you Identify

A

First make chromatograms for your unknown substance and for some reference materials ( dyes you that you think might be in the ink)
Compare the chromatograms to work out what dyes are in your unknown substance - spots on the chromatogram for the unknown substance will match spots on the chromatograms of the reference materials when the dyes are the same

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22
Q

When do you use simple distillation?

A

Separating out a liquid from a solution

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23
Describe how Simple Distillation is used to separate out solutions
1. The solution is heated. The part of solution that has the lowest boiling point evaporates 2. Vapour is the cooled, condenses ( turns back into liquid) 3. Th rest of the solution is left behind in the flask
24
What problem is their for simple distillation?
Only use it to separate things with very different boiling points
25
Describe how Fractional Distillation works
1. Put your mixture in a flask and stick a fractionating column on top 2. The different liquids will all have different boiling points - so they will evaporate at different temperatures 3. The liquid with the lowest boiling point, evaporate first. When the temperature on the thermometer matches the boiling point of this liquid, it will reach the top of the column 4. Liquids with higher boiling points might also start to evaporate. But the column is cooler towards the top. So they will only get part of the way up before condensing and running neck down towards the flask 5. When the first liquid has been collected, you raise the temperature until the next one reaches top
26
Periodic table shows the elements in order of increasing...
Atomic number
27
Vertical columns in the periodic table are called what?
Groups
28
What does the properties of elements depend on?
The number of electrons they have | And number on the outer shell
29
Giant Ionic structures have what?
High melting and boiling points
30
Why do Giant Ionic Structures have high melting and boiling points?
The ions are held together in a closely in a closely packed 3D lattice arrangement by the attraction between oppositely charged ions The electrostatic attraction between oppositely charged ions is very strong A lot of energy is needed to overcome the strong attraction, this means that ionic compounds have high melting and boiling point.
31
When an atom loses electrons, it's called
OXIDATION
32
When an atoms gains electrons, it's called
REDUCTION
33
What are cations?
Positive ions
34
What are anions?
Negative ions
35
Describe the forces of attraction between molecules and what is the result of this?
Forces off attraction are very weak Result of these feeble intermolecular forces is that the melting and boiling points are very low, because the molecules are easily parted Most molecular substances are gases or liquids at Room temp
36
Describe Giant Covalent Structures
All the atoms are bonded to each other by strong covalent bonds There are lots of these bonds which means it takes a lot of energy to break them so giant covalent structures have very high melting and boiling points Don't conduct electricity even when molten except graphite Usually Insoluble in water
37
Describe the structure of a Diamond
Each Carbon atoms forms four covalent bonds in a very rigid giant covalent structure This structure makes diamond the hardest natural substance, so it's used for drill tips and cutting tools Sparkly and pretty top
38
Why is Graphite the only non-metal which is a good conductor of electricity?
In Graphite, each carbon atom only forms three covalent bonds, creating layers which are free to slide over each other This makes graphite useful as a lubricant Also leaves free electrons, which conduct electricity
39
What are Isotopes?
Atoms of the same element which have the same number of protons but different number of neutrons
40
What is Relative Atomic Mass (Ar)
a measure of the mass of one atom of the element. | How heavy different atoms are compared with the mass of an atom of carbon-12
41
What is relative abundance
How much there is of each isotope compare to the total amount of element in the world. This can be a ratio, a fraction of a percentage
42
Equation to find a percentage yield?
Actual yield/ theoretical yield
43
What is the molar mass?
The mass of one mole
44
What is Avogadro's number?
6.023x10 to the power of 23
45
What is water of crystallisation?
Water in a lattice
46
A solid salt containing water of crystallisation is what?
Hydrated
47
If a salt doesn't contain any water o crystallisation, what is it called?
Anhydrous
48
Why don't solid ionic compounds conduct electricity?
Because the ions aren't free to move around
49
When can ionic compounds conduct electricity?
When an ionic compound is dissolved the ions separate and are free to move in the solution. Thus means that they'll carry electric current and conduct electricity When an ionic compound melts, the ions are also free to move and will carry electric current
50
Why don't covalent bonds conduct electricity?
They make bonds by sharing electrons which means they don't have any charge carriers that are free to move - so they can't carry an electric current
51
How are metals held together? Describe their structure as well.
Have a giant structure of positive ions surrounded by a sea of delocalised (free) electrons The attraction between the positive ions and the electrons is called metallic bonding This metallic bonding gives metals their properties
52
Describe why Metals are good conductors of Electricity and Heat
The free electrons carry electric current and heat energy through the material
53
Describe how most Metals are Malleable
The layers of atoms in a martial can slide over each other, making metals malleable - this means that they can be hammered or rolled into flat sheets
54
Electrons are taken away from ions...
At a positive electrode (anode) and given to other ions at a negative electrode (cathode)
55
In Electrolysis as ions gain or lose electrons, they become...
Atoms or molecules
56
How are electrolytes made in electrolysis?
By melting or dissolving ionic substances
57
At the anode, if no halide ions are present, what will be formed?
Oxygen
58
At the anode if OH- and halide ions are present (Cl-, Br- and I-) what will be formed
Chloride, bromide and Iodide molecules
59
A solution of Sulfuric acid contains which ions?
Sulfate ions - SO42- Hydrogen - H+ Hydroxide - OH-
60
In the Electrolysis of sulfuric acid, what is produced at the cathode? What is the Half equation for this?
Hydrogen ions from the water or Sulfuric acid accept electrons 2H+ +2e- → H2
61
In the Electrolysis of Sulfuric Acid, what is produced at the anode?
Oxygen and Waterv Hydroxide ions lose electrons more easily than Sulfate ions 4OH- → 2H2O + O2 + 4e-
62
In the solution of copper Sulfate, what ions do they contain?
Copper - Cu2+ Sulfate - SO42- Hydrogen - H+ Hydroxide ions - OH -
63
In the electrolysis of copper Sulfate, what is produced at the cathode? What's the half equation for this
Copper Metal Copper ions accept more easily than hydrogen ions At the cathode: Cu2+ + 2e- → Cu
64
In the electrolysis of Copper (||) Sulfate, what is made at the anode? What are the half equations
Oxygen and Water Hydroxide ions lose electrons more easily than Sulfate ions 4OH- → O2 + 2H2O + 4e-