Elements of life(EL) Flashcards

1
Q

Group 2 element + oxygen

A

metal oxide and bright flame

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2
Q

Group 2 element + water

A

metal hydroxide and hydrogen
bubbles

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3
Q

Group 2 element + acid

A

salt and hydrogen
bubbling

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4
Q

Group 2 oxide + water

A

metal hydroxide

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5
Q

What happens to reactivity as you go down group 2?

A

Increases

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6
Q

Why does reactivity increase as you go down group 2?

A

1.)There is more shielding of outer electrons
2.)The attraction between the positive nucleus and outer electrons decrease
3.)The first and second ionisation energies increases

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7
Q

What happens to solubility as you go down group 2?

A

Increases

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8
Q

What is magnesium hydroxide,Mg(OH)2,used for?

A

Heartburn or Acid reflux

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9
Q

What is calcium hydroxide,Ca(OH)2 used for?

A

Agriculture,to neutralise acidic soil

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10
Q

Relative mass of an electron

A

1/2000

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11
Q

Define atomic number

A

The number of protons (or electrons) in an atom

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12
Q

Define mass number

A

The number of protons and neutrons in the nucleus of an atom

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13
Q

Define isotopes

A

Atoms with the same number of protons and electrons but different number of neutrons

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14
Q

Why do isotopes have slightly different physical properties?

A

Physical properties are often dependent more on the mass of the atom

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15
Q

Equation that links no. of moles,concentration and volume

A

No. of moles=concentration x volume (in dm3)

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16
Q

What is an ionic equation?

A

An ionic equation doesn’t include the spectator ions

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17
Q

What is an empirical formula?

A

The smallest whole number ratio of atoms in a compound

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18
Q

What is a molecular formula?

A

The actual number of atoms in a molecule

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19
Q

What is water of crystallisation?

A

Compounds with water molecules embedded into them

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20
Q

What happens when an ionic compund is dissolved in water?

A

The ions in its lattice seperate and are surrounded by a sphere of water molecules

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21
Q

Do hydrated or anhydrous compounds contain water of crystallisation

A

Hydrated

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22
Q

How do you calculate the formula of a hydrated compound from it anhydrous compound once water has been lost?

A

1.)Find the number of moles of water
2.)Find the number of moles of anhydrous salt
3.)Work out the ratio of moles of anhydrous salt to moles of water

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23
Q

What happens when a solid salt crystalises from an aqueous salt solution?

A

Water molecules become woven into the crystal lattice structure

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24
Q

How to calculate percentage yield?

A

percentage yield= actual yield/theoretical yield x 100

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25
Q

How to calculate the theoretical yield?

A

calcuate the moles of the reactant(s) then multiply by the Mr of the product

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26
Q

Why is percentage yield not 100%?

A

-Practical losses e.g during filtartion
-Icomplete reactions
-Side reactons

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27
Q

What are the four sub-shells?

A

s,p,d and f

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28
Q

How many electrons can each sub-shell hold?

A

-s=2
-p=6
-d=10
-f=14

29
Q

What is an orbital?

A

The bit of space where an electron moves in

30
Q

What is spin-pairing?

A

Electrons in orbitals have to ‘spin’ in opposite directions

31
Q

What is the shape of a s orbital?

A

Spherical

32
Q

Why are elements in the periodic table placed into s,p,d and f blocks?

A

The elements have an outer shell electron configuration with the respective sub-shell

33
Q

What is the shape of a p orbital?

A

Dumbell

34
Q

Why does the 4s shell fill up before the 3d shell?

A

The 4s shell is is lower in energy than the 3d shell, so the atom is more stable

35
Q

What does ionic bonding occur between?

A

Metal and non-metal

36
Q

What is electrostatic attraction?

A

The forces which hold positive and negative ions together

37
Q

What happens within a lattice (attraction and repel)?

A

The ions with different changes attract each other and the ions with the same charge repel each other

38
Q

Do ionic compounds conduct electricity?

A

Only when molten or dissolved

39
Q

Why do ionic compounds only conduct electricity when molten or dissolved?

A

The ions are free to move and carry a current

40
Q

Why do ionic compounds have high melting points?

A

The giant ionic lattice is held together by strong electrostatic forces which takes a lot of energy to overcome

41
Q

Why are ionic compound soluble?

A
  1. Water molecules are polar
  2. Parts of the molecule have small negative charges and others have positive
  3. Water molecules pull ions away from the lattice causing it to dissolve
42
Q

What are polyatomic ions?

A

when an ion contains more than one atom

43
Q

What factors affect the strength of ionic bonding?

A

-The charge of the ions
-The size of the ions

44
Q

What happens to the size of ions as you go down a group?

A

Increases

45
Q

Three points

Why does first ionisation enthalpy increase across period 3?

A
  • The electrons are removed from the same shell
  • The number of protons and nuclear charge increases across the period
  • Electrons are more strongly attracted to nucleus
    (shielding of outer electrons remain the same)
46
Q

What are the observations for sulfuric acid with Barium,lead and iron?

A
  • Ba/Pb~white percipitate
  • Fe~no reaction
47
Q

What are the observation for potassium iodide with barium,lead and iron?

A
  • Ba~colourless
  • Pb~Yellow percipitate
  • Fe~No reaction
48
Q

What are the observations for sodium hydroxide with barium,lead and iron?

A
  • Ba~colourless
  • Pb~White percipitate
  • Fe~dirty green percipitate
49
Q

What is cause

What acid is used to detect carbonates?

A

Hydrochloric acid~fizzes as it gives of CO2 which turns limewater cloudy

50
Q

How can you convery kJ into kJ mol -1?

A

Multiply by 6.023 x 10(23)

51
Q

Fuve points

Explain how elemntts give off coloured lights when heated

A
  1. Heated elements absorb energy-electrons become excited
  2. Electrons promoted to higher energy levels
  3. Electrons drop back down to lower energy levels-emit a photon of energy~dependent on the gaps between energy levels (E=hv)
  4. If the frequency is in the visivble region oof the EM spectrum, element will have a colour
  5. Energy level unique each elemnts, produce unique spectrum
52
Q

4 points

Describe how to compare thermal stabilities of calcium carbonate and strontium carbonate

A
  1. Take sample of known moles of CaCO3 in sealed boiling tube, heat with busen burner
  2. Place delivery tube from boiling tube into a sample of limewater-time how long it takes for limewater to turn cloudy
  3. Thermal decomposition of metal carbonates produces CO2 which turns limewater cloudy
  4. Repeat using same moles of SrCO3,results are valid,ensure distance of flame to boiling tube is clear
53
Q

How to convert cm3 to dm3?

A

Divide by 1,000

54
Q

What equation links volume and moles at RTP?

A

volume=moles x 24dm3

55
Q

What type of bonding and structure is found in sulfur?

A
  • Simple molecular
  • Lattice
56
Q

What equation links speed of light,wavelength,planck constant and energy?

A

E=hc/λ

57
Q

Why does the thermal stability of the group 2 carbonates increase down the group?

A
  1. Group 2 cations have a lower charge density going down the group
  2. This causes less polorisation/distortion of the carbonate ions and greater thermal stability
58
Q

What is the equation that links concentration,volume and moles together?

A

n=c x v

59
Q

How do you calculate the % uncertainty?

A

uncertainty/measure value x 100

60
Q

How do you convert g dm-3 into mol dm-3?

A

Divide by the molar mass

61
Q

What is the shape and angle when a central atoms has:
* 2 AOED
* 3 AOED (lone pair)

A
  • 2 AOED=Linear~180
  • 3 AOED=Trigonal planar (lone pair~non-linear) both 120
62
Q

What is the shape and angle when central atom has:
* 4 AOED (one or two lone pairs)
* 5 AOED
* 6 AOED

A
  • 4 AOED=tetrahedral~109.5 (one lone pair=trigonal pyramidal~107/two lone pairs=non-linera~104.5
  • 5 AOED=trigonal bipyramidal~120
  • 6 AOED=octrahedral~90
63
Q

Define first ionisation enthalpy

A

The energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 molecule og gaseous 1+ ions

64
Q

Three points

What affects ionisation enthalpies and give a basic description why

A
  1. Atomic radius~further outer electron shells less they are attracted towards the nucleus=lower enthalpy
  2. Nuclear charge~more protons in nucleus,the more it’ll attract the outer electrons=harder to remove electrons-enthalpy is higher
  3. Electron shielding~inner electrons shield outer electrons from attractive force of the nucleus=enthalpy lower
65
Q

Two points

Why do first ionisation enthalpies decrease down a group?

A
  1. Outer electron shells are further from the nucleus=Attracted to the nuclueus less
  2. Amount of shielding increases as there are more filled inner shells=less nuclear attraction for outer shell electrons
66
Q

Why do first ionisation enthalpies increase across a period?

A
  1. Number of protons increasing=outer electrons are attracted more strongly to nucleus
  2. Little extra shielding or extra distance to lessenn attraction from nucleus
67
Q

Why do s-block metals have low ionisation enthalpies?

A

They have relatively low nuclear charges=they lose their outer electrons easily~there is less attraction between nucleus and outer electrons

68
Q

What colour precipitate is formed when NaOH is added to:silver,calcium,copper,lead,iron(II) and iron(III)

A

Silver=Brown Calcium=white Copper=blue Lead=white Iron(II)=Green Iron(III)=reddish brown

69
Q

How do you test for sulfates and ammonium compounds?

A
  • Sulfates=Add dilute HCl and barium chloride solution~white ppt
  • Ammonium compounds=add NaOH solution and gently heat~ammonia is given off turns damp red litmus paper blue