C1, C2 Flashcards

1
Q

What is an element?

A

All the atoms are the same

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2
Q

What is a compound?

A

When you chemically combine 2 or more elements

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3
Q

What is a fixed proportion?

A

For every one atom of an elements there is another atom

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4
Q

How do you turn compounds back into their elements?

A

Make a chemical reaction

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5
Q

What is a mixture?

A

When you have different elements or compounds but not chemically combined

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6
Q

How do you seperate a mixture?

A

By using filtration,distillation or crystilisation

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7
Q

What can physical seperation techniques be only used to seperate?

A

Mixtures

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8
Q

What is filtration used to seperate?

A

An insoluble solid from a liquid

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9
Q

What does insoluble mean?

A

Not dissolve in the liquid

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10
Q

What equipment do you need for filtration?

A
  • Filter funnel
  • Filter paper
  • Conical flask
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11
Q

What is crystilisation?

A

Used to seperate a soluble solid from a liquid

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12
Q

What are the steps of crystalisation?

A

1) Pour the solution in a evaporating dish and heat the dish. Some will evaporate, some willget more concentrated
2) Once some of the solvent has evaporated or when you see crystals start to form. Remove the dish from the heat and leave the solution to cool
3) The salt should start to form crystals and becomes insoluable in the cold
4) filter the crystals out in the solution and leave them in a warm place to dry

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13
Q

What is the disadvantage of crystilisation?

A

When you heat them chemicals will break down

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14
Q

What is simple distilation great for,?

A

Seperating salt water from drinking water

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15
Q

What is simple distilation good for?

A

When you want the solid and the liquid

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16
Q

Whats the equipment for simple distillation?

A
  • Themometer
  • Condenser
  • Pot
  • Receiver flask
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17
Q

What are the steps for simple distilation?

A

1) Solution is heated and the part that has the lowest boiling point evaporates first
2) The vapour is cooled and condensed and turned back into a liquid and collected
3) The rest of the solution is left in the flask

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18
Q

Whats the main disadvantage of using simple distilation?

A

You can only seperate things with different boiling point

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19
Q

Whats the equipment for fractional distilation?

A
  • Pot
  • Themometer
  • Condenser
  • Fractionating column
  • Beaker
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20
Q

Disadvantage of using fractional distilation?

A
  • When theyre similar temperature you need to carry out more rounds of fractional distilation
  • The equipment is not useful when you want to seperate large volumes of liquid
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21
Q

Steps for fractional distilation?

A

1) Put the mixture in the pot/flask with a fractionating column on top and heat it
2) The liquid with the lowest boiling point evaporates first and when the themometer matches the boiling point you know it’s reached the top
3) Liquids with high boiling points might start to evaporate but the column is coller at the top so they will run back down.
4) Put a beaker and collect the 2 chemicals

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22
Q

What are physical processes?

A

Dont involve chemical reaction and no new substances are made

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23
Q

What does chromatography help you do?

A

Seperate differnt substances based on their solubilities

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24
Q

What do you call the paper in chromatography?

A

The stationary phase

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25
Q

What do you call the solvent in chromatography?

A

Mobile phase because the solvent moves

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26
Q

What will a pure compound produce is chromatography?

A

A single spot in solvents

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27
Q

What will a mixture produce in chromatography?

A

Seperate into differnt spots

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28
Q

Why does paper chromatography work?

A

Differnt substances have differnt sollubilities

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29
Q

Why do you draw the starting line in pencil chromatography?

A

The pen ink will disolve and the solvent in it will move up the paper

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30
Q

What’s an example where you can use chromatography?

A

Seperate different dyes in ink

31
Q

Steps for chromatography?

A

1) Draw a line on the bottom of the filter paper
2) Add a spot of ink on the paper
3) put lid on the beaker so it doesn’t evaporate
4) The dyes will then move up the paper at differnt rates
5) You know which one is pure and which one isn’t when there is one pure substance

32
Q

What did scientist beleive in 1897?

A

Atoms contained tiny negative particles (electrons)

33
Q

What did the discovery of electrons tell scientsists?

A

Atoms are tiny spheres that cannot be divided and atoms must have an internal structure

34
Q

What did the Greeks beleive 1000 of years ago?

A

Atoms are tiny spheres which cannot be divided and everything is made up of atoms

35
Q

Whats in the plum pudding model?

A
  • Electrons embeded in it
  • Ball of positive charge
36
Q

What’s the alpha scattering experiment?

A

Scientist took a peice of gold foil (because its very thin). They then fired atoms into the gold foil (alpha particles) which were positive charge.

37
Q

What was the result from the alpha scattering experiment!

A

Atoms passed straight through the gold foil without changing direction .but sometimes they deflected and changed direction and sometimes they bounced back

38
Q

What did scientsist conclude from the alpha particle experiment?

A
  • When atoms went through the gold foil it told scientists that it was mostly empty space so plum pudding model had to be wrong.
  • When atoms were deflected this told scientists that the centre of the atom must have a positive charge.
  • Some particles bounced back and told scientists that the atom must contain great mass
39
Q

What came after the plum pudding model?

A

Nuclear model

40
Q

Describe the nuclear model?

A
  • Positive nucleus in middle with electrons surrounding it
41
Q

What did Neil Bohr propose?

A

Electrons orbit the nucleus at specific distances

42
Q

What do protons drermine?

A

The amount of positive charge in the nucleus

43
Q

What did James chadwick discover?

A

Nucleus also contains neutral particles (neutrons

44
Q

Whats the radius of an atom?

A

0.1 nm

45
Q

Whats the radius of the nucleus?

A

1 x 10-14

46
Q

Why do atoms have no overall charge?

A

Protons are the same as electrons

47
Q

Whats an isotope?

A

Isotopes are atoms of the same element with differnt number of neutrons

48
Q

What is an ion?

A

Atoms which have an overall charge

49
Q

What does abundance mean?

A

How common an isotope is

50
Q

Relative atomic mass equation?

A

(Mass number of isotope 1 x percent abundance of isotope 1) + (mass number of isotope 2 x percent abundance of isotope 2) / 100

51
Q

Energy level format?

A

2,8,8,18

52
Q

Why is it called the periodic table?

A

To put elements with similar properties together

53
Q

What did the scientist Johann dobereiner notice?

A

Elements with similar chemical properties occured in threes (triads)

54
Q

What did John newland notice?

A

The 8th element reacts in a similar way (law of octaves)

55
Q

Why did scientists not take newlands law seriously?

A

Elements were grouped together and had different properties

56
Q

Who was dimitri mendeleev?

A

Discovered the 1st periodic table

57
Q

How did mendeleev discover the periodic table?

A

He arranged them in weight. If needed to he would switch elements so they fitted pattern in the same group. He also realised some had not been discovered so he left gaps and predicted the properties of them elements. Several years later the elements were found and matched mendeleevs experiment and sciientists accepted his experiment

58
Q

How is mendeleevs table differnt to the periodic table?

A
  • The atoms are arranged in order of atomic number
  • The modern periodic table has noble gases which wasn’t discoverd back then
59
Q

Whys it not good to arrange by atomic weight?

A

They can appear in the wrong order due to isotopes

60
Q

Facts about group 8 (noble gases)

A
  • Very unreactive
  • All noble gases have a full outer energy level
  • The boiling points increase going down the group
61
Q

Why are noble gases unreactive?

A

They have a full outer shell and are stable so are unreactive

62
Q

Facts about metals?

A
  • When metals react they lose electrons to acheive a full outter shell
  • Same electronic structure as noble gas
  • Always form positive ions
63
Q

When metals react what happens?

A

They lose there outer ekectron shells

64
Q

How do group 1 metals react with oxygen?

A

React rapidly and more going down the group

65
Q

How do group 1 metals reacts with chlorine ?

A

Rapidly

66
Q

An example of a group 1 metal reacting with water?

A

2 Li + 2H2O = 2LiOH + H2

67
Q

Why do elements get more reactive moving down group 1?

A

Moving down group 1 The outer electron is less attracted to the nucleus and easier to lose. Because there is a greater distance between the nucleus and neg electron

68
Q

What is the calling of sharing electrons?

A

Covalent bond

69
Q

A fact about group 7 elements?

A
  • Form covalent compounds when they react with non metals
  • Form ionic compounds with metals
  • The elements get less reactive down the group
  • A more reactive halogen displaces a less reactive halogen from an aquesous solution of its salt
70
Q

Why is it less reactive down the group?

A

Greater distance from nucleus
Sheilding by internal electrons

71
Q

Things about group 1 metals?

A
  • Soft metals
  • Low melting points
  • Low density
  • React rapidly with oxygen,water and chlorine
  • Forms +1 ions
72
Q

Properties about transition elements?

A
  • Hard and strong
  • High melting points
  • High density
  • Much less reactive that group 1 metals
  • Can form ions with differnt charges
73
Q

Things anout transition elements?

A
  • Form ionic compounds
  • Can be used as catalysts