C2 Flashcards

1
Q

What is an ion?

A

Charged particles can be made of single atom (Cl-) or group (NO3-)

metal= lose= +, non-metal= gain -

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2
Q

Why do atoms try to gain a full outer shell?

A
  • Lose or gain electrons to gain full outer shell
  • Full outer shell called stable atomic structure it is a very stable element

Groupo 0= full outer shell

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3
Q

Draw the half eqation for Na when forming an ion

group 1

A

Na-> Na(=) + e(-)

loses 1 electron

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4
Q

Draw the half eqation for O when forming an ion

Group 6

A

O+ 2e(-)->O^(2-)

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5
Q

What is ionic bonding?

A
  • Metal+ Non-metal react together
  • Metal becomes positive +
  • Non-metal becomes negative -
  • There are strong electrostatic forces for attraction between the oppositly charged ions= ionic bond
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6
Q

Draw a dot and cross digram for Magnesium chloride (MgCl2)

A
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7
Q

What is the structure and forces of ionic compounds?

A
  • Giant ionic lattice
  • Ions are closely packed in regular lattice arragment
  • Very strong electrostatic forces of attraction between the ions in all directions
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8
Q

What are the properties of ionic compounds? Justify why.

A
  • High **melting **and boiling points-> strong bonds between ions require lots of energy to overcome
  • Cann’t conduct when solid-> ions are held in place
  • Can conduct when molten-> ions free to move= carry electric current
  • ** Can conduct** when dissolved in water-> ions are seperate and free to move in soltion=carry current
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9
Q

What is the empirical formular of the ionic compound below?

A
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10
Q

What is covalent bonding?

A
  • Non-metal + Non-metal bond bond together sharing electrons (outer shell) to make colavlent bonds
  • positivly charged nucli of bonded atoms are attracted to shared pair of electrons by electrostatic forces= strong covalent bonds
    *
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11
Q

Draw the dot and cross digram to show the bonding in NH3

A
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12
Q

What does the dot and cross digram show?
What are the limitations of the dot and cross digram?

A

+dot and cross show ere each electron comes form
+ good for showing large molecules
- - Dosn’t show relative sizes of the atoms or how they are arraged in a space
- Dosn’t show the 3D structure of the molecule or

£d ball and stick digrmas can get very confusing

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13
Q

What is the bonding and structure of simple molecular subsances?

A

Molecules containg a few atoms joined together by covalent bonds

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14
Q

What is the bonding and structure of Hydrogen?

A
  • 1 electron, one more needed to complete the first shell
  • Bonds to form single covalent bonds e.g with hydrogen
  • Simple molecular
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15
Q

What is the bonding and structure in Nitrogen?

A
  • Needs 3 more electrons
  • 2 nitrogent atoms shre 3 pairs of electrons
  • Triple bond
  • Simple molecular
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16
Q

What are the properties of simple molecular substance? Why is this?

A

Bonding:
* Substances containing covalent bonds usally= simple molecular structure
* Atoms within moleculs held together with very strong covalent bonds
* However…….. forces of attraction between molecules ( intermolecular) forces are very weak
Properties:
* Melting point is very low-> Only need to break feeble intermolecular forces not covalent= moleculs are easly parted
* Most molecualr substances are gass at room temp ( oxygen).
* Don’t conduct electrity-> arnt charged ions= no free elctrons/ions

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17
Q

What happens to the properties of a simple molecular subtance as it gets bigger?

A
  • Bigger= strength of the intermolecular forces increase=> more energy needed to break them=> increased melting and boiling points
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18
Q

What is a polymer? What kind of bonding has it got?

A
  • Giant covalent substance
  • Lots of small units linked together to form a long molecule with reapeating sections
  • All atoms in polymer joinged by strong covalent bonds
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19
Q

Whta re the properties of polymers and explain them.

A
  • Solid at room temp->Intermolecular forces bewtween molecules are larger then simple covalent=> more energy needed to break them.
  • Low melting and boiling points-> intermolecular forces are weaker thne ionic + covalent= lower boiling points than ionic/ giant compounds
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19
Q

What are the general properties and structure of Giant covalent structures?

A
  • All atoms are bonded to each other by strong covalent bonds
  • Very high melting and boiling points= lots of energy needed to break the covalent bonds between atoms
  • Don’t conduct electrity->( even when molten) Don’t contain charged particels (some exceptions).
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19
Q

Describe the bonding and structur in Silicon dioxide

A
  • Sometimes called silica
  • Giant covalent structure
19
Q

Describe the structure and properties of diamond.

Uses

A
  • Giant covalent structure
  • Made of carbon atoms, each carbon forms 4 covalent bonds-> realy hard
  • Very high melting point->Strong covalent bonds take a lot of energy to break
  • Donsn’t conduct-> no free electron

Jewlery, drill bits

19
Q

Describe the structure and properties of Graphite.

Uses

A
  • Each carbon atom forms 3 covalent bonds=> sheets of carbon atoms arranged in hexagons
  • Soft and slippery (Lubricationg material)->No covalent bonds between layers, held together weakly=> free to move over each other
  • High melting point-> covalent bonds between layer= lots of energy to break
  • Conducts electrity and thermal energy-> 3 of 4 of carbons outer electrons used in bonds= delocalised elecctron with is frre to move and carry a charge through the structure

Lubrication materials

20
Q

Describe the structure and properties of Graphene

A
  • Sheet of carbon atoms joined together in hexagons, 1 atoms thick ( 2D)
  • Network of covalent bonds->strong
  • 1 atom thin-> light & added to composite materilas to improve strenght without adding to weight
  • can conduct elecricity-> delocalised electron can carry a charge through the structure=> electronics

electronics, added to compostive materials

21
Q

What are fullerens?

A
  • Fullerene-> Molecule of carbon shaped in closed tubes or hollow balls
  • Can be in hexagons, pentagons………
  • Deliver drugs ( around body)-> Can ‘cage’ other molecule
  • Catalyst-> Huge SA= moleculas can be attached to fullerne

Lubricans, drug delivery, catalyst

22
Q

What is Buckminsterfullerene?

A

First fulleren discovered, hollow sphere

23
Q

What are nanotubes

A
  • Fullerene
  • Tiny carbon cylinder
  • High length to diameter ratio
  • Conduct themal + electrical energy
  • High tensile strength( don’t break when streched)
  • Nano tech: electronics, strenghten materials withought adding to weight (tennis racket frames)
23
Q

Describe the structure and properties of metalic bonding.

A
  • Giant structure
  • Electrons in outer shell= delocalised
  • Strong forces of electrostatic attraction between positive metal ion and shared negative electrons
  • Metalic bonding ->Forces of attraction hold atoms together in regular structure, very strong bonding
  • Metalic bonding is in alloys and metals
23
Q

What is the trend in boiling points in metallic bonding?

A
  • Electrostatic forces between metal atoms and delocalised sea of elctrons are strong and need lots of energy to be brocken
    Hence:
    ->Very high melting point
    -> solid at room temp
23
Q

Do matalic substances conduct electrcity?

A

Can conduct heat and electricity
Delocalised electron is free to carry a charge through the structure

23
Q

Are metalic substances malleable?

A

Layers of of atoms can slide over each other= malleable
Can be bent hammered or rolled into falt sheets

24
Q

Why are Alloys harder then pure metals?

A
  • Pure metal= too soft
  • Alloys=harder than pure metals
  • Diffrent elements have diffrent sized atoms so when anouther element is mixed with pure metal=it distorts the layers => more difficult to slide over each other=> harder than pure metals
24
Q

Define Alloy

A

Alloy-> mixture of two or more metals of anouther element

24
Q

What determins the state of a material?

A
  • Depends on how strong the forces of attraction between thae particles of the material
    Strength of forces baised on:
    1) Material (structure and bonding bewtween particles)
    2) Temp
    3) Pressure
25
Q

In a solid decribe the forces flow ect.

A
  • Strong forces of attraction between particles holding them close together in fixed positions in very regular lattice arrangement
  • Don’t move from their postion all solids keep definte shape and volume
  • Don’t flow
  • Vibrate about there postions: the hotter solid becomes= more they vibrate ( expand when heated
26
Q

In a liquids decribe the forces flow ect.

A
  • Weak force of attraction between particles
  • Randomly arranged and free to move past each other but stick closly together.
  • Liquids have definite vol don’t keep definite shape ( fill bottem of a container)
  • Particles move constantly with random motion. Hotter liquid gets the faster they move ( expand when heated).
27
Q

In a gases decribe the forces flow ect.

A
  • In gasas force of attraction between particles are weak, thy’re free to move far apart
  • Particles move in staight lines
  • Gasas don’t keep definte shape/vol and will fill container
  • The particles move constantly with random motion. hotter gas gets= faster they move (eather expand when heated or preasure increases).
28
Q

What are the issues with the particle theory of states of matter?

A
  • Particles arn’t solid or inelastic and not spheres they’re atoms ions or moleculs.
  • Don’t show the forces between particles= can’t see the strength of them
29
Q

What does Aqueous mean?

A

Dissolved in water (aq)

30
Q

What is a physical change?

A

No change of particles just their arrangement or energy

31
Q

Describe what happens when a solid is heated to liquid?

A
  1. Solid is heated it’s particles gain more energy.
  2. Makes particles vibrate more which weakens the forces that hlod solid together.
  3. At certain temp (meltiong point) particles have enough energy to break free form their postions= melting S->L
32
Q

What happens when a liquid i heated to a gas?

A
  1. Liquid is heated the particles get even more energy
  2. This energy makes the particles move faster which weakens and breaks the bonds holding the liquid together
  3. At certain temp (boiling point) particles have enough energy to break their bonds=boiling ( evapourationg)
    L->G
33
Q

What happens as a gas cools into a liquid?

A
  1. As gas cools particles no longer have enough energy to overcome forces of attraction between them.
  2. Bonds form between particles
  3. At boiling point so many bonds have formed between gas particles that the gas becoms liquid=Condensation
34
Q

What happens when a liquid cools into a solid?

A
  1. Liquid cools particles have less energy
  2. There’s not enough energy to overcome attraction between particles so more bonds form between them
  3. At the melting point so many bonds have formed that they’re held in places. L->S= freezing
35
Q

What is the convertion: 1nm->xm

A

1nm= 0.000,000,001

36
Q

What is a coarse particle?

A

PM10
diameter 2,500nm-10,000nm
Also called dust

37
Q

What is a fine particles

A

PM2.5
diameter 100nm-2500nm

38
Q

What is a nanoparticle?

A

diameter 1nm-100nm
They only contain a few hundred atoms

nanoscience-> science that looks at uses+ properties of nanoparticles

39
Q

What are the properties of nanoparticles?

A
  • Nanoparticles have high SA:Vol-> As particles decrease in size their SA:Vol increases ( very high SA compaired to it’s vol)
  • This chages propeties of material depending if it’s a nanoparicle or in bulk e.g. leff on catalyst made of nanopartices compaired to noramal sized particles (with billions of atoms)
40
Q

What are the uses of Nanoparticles?

A
  • Catalysts-> high SA:Vol
  • Nanomedicine-> tiny particles (e.g fullerenes) are absorbed into body more quickly= could deliver drugs to specific cell in wich they are needed.
  • Electric circuits->Conduct electricty= computer chip
  • Surgical masks, wound dressings, deodorants-> Silver nanoparticles have antibacterial properties. Can be added to polymer fibers.
  • Cosmetics->e.g added to improve moisturisers without making them oily

sunscreen

41
Q

Why may some be against Nanoparticles?

A
  • They way they affect the body isn’t fully understood=> should be testing on new products to decrease risk
  • Some say it has been used without knowlage of it’s impact long term
  • Nanoparticles are clearly labled= consumer chose
42
Q

How and why are nanoparticles used in sunscreen? What are the downsides?

A
  • Nanoperticles are better thhan traditional at protecting form UV
  • Better skin coverage
  • Not clear if nanopartices can enter body and if that may damage cells
  • When washed away may damage the enviroment