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Chemistry - norm > 1 - 1 - Principles of Chemistry > Flashcards

1 - 1 - Principles of Chemistry Flashcards

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1
Q

How are the particles arranged in a solid?

A
  • Strong forces of attraction between particles which folds them close together in fixed positions in a lattice arrangement
  • The particles don’t move from their position, keep a definite shape and volume
  • The particles vibrate in position
  • The hotter they become the more they vibrate
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2
Q

How are the particles arranged in a liquid?

A
  • Weaker force of attraction between particles
  • Randomly free to move past each other but still stay close together
  • Have a definite volume but no definite shape
  • Particles are constantly moving in a random motion
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3
Q

How are the particles arranged in a gas?

A
  • Very weak forces of attraction
  • Far apart and move freely but in straight lines
  • No definite shape or volume and will fill any container
  • Constantly move in a random motion
  • ## When temperature increases the pressure increases
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4
Q

What is melting?

A

Solid to liquid

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5
Q

What is evaporating?

A

Liquid to gas

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6
Q

What is condensing?

A

Gas to liquid

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7
Q

What is freezing?

A

Liquid to solid

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8
Q

What is subliming?

A

Solid to gas

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9
Q

Describe an experiment to show diffusion in water

A
  • Potassium manganite (VII) in water

- The bright purple colour will slowly diffuse

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10
Q

Describe an experiment to show diffusion in water

A
  • Potassium manganite (VII) in water
  • The bright purple colour will slowly diffuse out
  • The solution can be diluted further by adding more water
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11
Q

Describe an experiment to show the random motion of particles in air

A
  • Fill half a gas jar with bromine gas (brown) and the other half with air separating it with a glass plate
  • If you remove the glass plate the bromine gas will slowly diffuse through the air
  • The random motion means that the bromine will eventually diffuse right through the air
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12
Q

Describe an experiment to show gas diffusion

A
  • Aqueous ammonia (NH3) gives off ammonia gas
  • HCl gives off hydrogen chloride gas
  • Soak two
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13
Q

Describe an experiment to show gas diffusion

A
  • Aqueous ammonia (NH3) gives off ammonia gas
  • HCl gives off hydrogen chloride gas
  • Soak two pieces of cotton wool in the liquids and put in a sealed glass tube
  • A ring of ammonia will form almost in the middle just slightly closer to the HCl
  • This is because the particles of ammonia are smaller and lighter so will diffuse more quickly
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14
Q

Nucleus

A
  • Middle of the atom
  • Contains protons and neutrons
  • Has a positive charge because of the protons
  • Almost the whole mass of the atom is concentrated in the nucleus
  • Very small
  • Relative mass of 1
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15
Q

Electrons

A
  • Move around the nucleus in energy levels called shells
  • Negatively charged
  • Tiny but cover a lot of space
  • Virtually no mass (1/2000)
  • Number of electrons = number of neutrons
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16
Q

Electrons

A
  • Move around the nucleus in energy levels called shells
  • Negatively charged
  • Tiny but cover a lot of space
  • Virtually no mass (1/2000)
  • Number of electrons = number of neutrons
  • If electrons are added or removed the atom becomes charged and is an ion
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17
Q

Atomic number

A
  • How many protons there are
  • The smaller number
  • Atoms of the same element will have the same number of protons
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18
Q

Mass Number

A

The number of protons and neutrons

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19
Q

What are molecules?

A
  • Groups of atoms
  • Can be made from one element of different elements
  • Held together by covalent bonds
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20
Q

What are elements?

A

One type of atom only

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21
Q

What are compounds?

A
  • A substance that is made of two or more different elements which are chemically bonded together
  • Difficult to separate
  • The properties of a compound are often totally different from the properties of the elements
22
Q

What are elements?

A

One type of atom only

e.g. oxygen

23
Q

What are compounds?

A
  • A substance that is made of two or more different elements which are chemically bonded together
  • Difficult to separate
  • The properties of a compound are often totally different from the properties of the elements
  • e.g. carbon dioxide
24
Q

What are mixtures?

A
  • No chemical bond between different parts of a mixture and can be separated through distillation
  • Properties of a mixture are just the properties of the separate parts
  • e.g. air
25
Q

When is filtration used?

A
  • To separate an insoluble solid from a liquid

- Can be used for purification as well

26
Q

Describe the process of crystallisation

A
  • Pour the solution into an evaporation dish
  • Slowly heat the solution
  • Some solvent will evaporate and the solution will become more concentrated
  • Stop heating when crystals start to form
  • Remove the dish and leave in a warm place for the rest of the solvent to evaporate
  • Dry the product using a drying oven or desiccator
27
Q

Describe how to use crystallisation and filtration to separate rock salt

A
  • Rock is a mixture of sand and salt which are both compounds
  • Grind it up using a pestle and mortar
  • Dissolve in a beaker and stir
  • Filter
  • Crystallise
  • The sand doesn’t dissolve so stays as grains that don’t fit through the filter paper
  • The salt is forms as crystals
28
Q

Describe how to use crystallisation and filtration to separate rock salt

A
  • Rock is a mixture of sand and salt which are both compounds
  • Grind it up using a pestle and mortar
  • Dissolve in a beaker and stir
  • Filter
  • Crystallise
  • The sand doesn’t dissolve so stays as grains that don’t fit through the filter paper
  • The salt is forms as crystals
29
Q

Describe how to paper chromatography

A
  • Draw a line near the bottom of a sheet of filter paper (in pencil)
  • Add spots of different dyes to the line at regular intervals
  • Loosely roll up the sheet and put in a beaker of water
  • Make sure the dyes aren’t touching the solvent
  • Put a lid on the container to stop the liquid evaporating
  • The solvent will seep up the paper carrying the dye with it
  • Each dye will move at a different rate and form a spot
30
Q

What is chromatography?

A

A method used to separate mixtures (can be on paper with dyes)

31
Q

how does chromatography separate mixtures?

A
  • The different dyes move at different rates
  • Some will stick to the paper and others will dissolve
  • The distance the dyes travel depends on the solvent and paper you use
32
Q

How does chromatography help identify dyes?

A
  • Make the chromatograms for the unknown substance and for some reference materials (dyes that you know)
  • Compare the chromatograms to work out what dyes are in your unknown substance
  • Some spots will match up with known dyes which must be in the unknown dye
33
Q

How does chromatography help identify dyes?

A
  • Make the chromatograms for the unknown substance and for some reference materials (dyes that you know)
  • Compare the chromatograms to work out what dyes are in your unknown substance
  • Some spots will match up with known dyes which must be in the unknown dye
34
Q

What is distillation? Describe how it is used

A

Separates a liquid from a solution

  • The solution is heated and the solution with the lowest boiling point evaporates
  • The vapours is cooled, condenses and is collected
  • The rest of the solution is left behind in a flask
  • Simple distillation can be used to get pure water from sea water
  • The problem is you can only get two things with very different boiling points
35
Q

What is fractional distillation? Describe how it is used

A
  • Used to separate a mixture of liquids
  • Put the mixture in a flask and put a fractionating column on top then heat
  • The different parts will evaporate at different rates
  • The liquid with the lowest boiling point will go to the top
  • Liquids with higher boiling points may start to evaporate
  • The column is cooler towards the top
  • When the first liquid has been collected raise the temperature to collect the next one
36
Q

What are features of groups in the periodic table?

A
  • Groups (down) are all elements with the same number of electrons on the outer shells
  • Have similar properties
  • The properties depend on the number of electrons
37
Q

What are features of groups in the periodic table?

A
  • Groups (down) are all elements with the same number of electrons on the outer shells
  • Have similar properties
  • The properties depend on the number of electrons
38
Q

What are the electron shell rules?

A
  • Electrons always occupy shells
  • The lower energy levels are always filled first
    1 - 2 electrons
    2 - 8 electrons
    3 - 8 electrons
  • Atoms want a full shell
  • The closer they are to a full shell the more reactive they are
39
Q

What is oxidation?

A

When an electron loses an electron OR gains oxygen

40
Q

What is reduction?

A

When an electron gains an electron OR loses oxygen

41
Q

What is ionic bonding?

A

The transfer of electrons by losing or gaining electrons to form a charged particle (an ion) which are then strongly attracted to one another (due to opposite charges)
This is known as the electrostatic attraction

42
Q

Which groups are most likely to form ions?

A

1 &2 (metals who lose an electron to form +ve ions), 6 & 7 (non-metals who gain an electron to form -ve ions)

43
Q

What are cations?

A

Positively charged ions

44
Q

What are anoins?

A

Negatively charged ions

45
Q

What are the properties of giant ionic structures?

A
  • 3D lattice arrangement
  • The electrostatic attraction is very strong
  • High melting and boiling points
  • The higher the charge the stronger the bonds (so higher melting and boiling points)
46
Q

What is covalent bonding?

A
  • Sharing electrons to make a full outer shell

- There is a strong attraction between the shared electrons and the nuclei of the atoms

47
Q

What is the symbol formulae for ammonia?

A

NH3

48
Q

What is the symbol formulae for ammonia?

A

NH3

49
Q

Simple molecular structures

A
  • Strong covalent bonds
  • Weak forces of attraction between molecules
  • Low melting and boiling points
  • Most are gases and liquids at rom temperature
50
Q

Giant covalent structures

A
  • No charged ions
  • Strong covalent bonds
  • Lots of bonds so high melting and boiling points- Don’t conduct electricity except when molten
  • Usually insoluble in water
  • Examples are diamond and graphite
51
Q

Diamond

A
  • Made of carbon atoms which each have four covalent bonds
  • The hardest natural substance
  • Used for drill tips and cutting tools
52
Q

Graphite

A
  • Made of carbon atoms which each make three covalent bonds, creating layers
  • The layers are free to slide over each other
  • Used as a lubricant
  • Has free electrons so is the only non-metal which is a good conductor of electricity

Chemistry - norm (6 decks)

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