Elements Of Life 🌲

Question 1

What is an isotope?

Answer 1

Same atomic number and a different mass number

Question 2

What is the plum pudding model?

Answer 2

The cell is a circle with mainly positive charged “pudding” and negative “plums” dotted around

Question 3

How was the plum pudding model proved wrong?

Answer 3

• alpha particles fired at sheet of gold
• were expecting alpha partciles to be reflected back at odd angles
• went straight through though.
• some went back 90° too
• nucleus in the centre

Question 4

How was the neutron discovered?

Answer 4

• realisation that nucleus heavier than just protons

- must be other stuff in there

Question 5

What are relative masses?

Answer 5

Masses of atoms compared to carbon-12

Question 6

What is a mole?

Answer 6

Amount of a substance

Question 7

Moles=?

Answer 7

Particles you have/ avogadros constant

Mass/ mr

Conc x volume

Vol/ 24

Question 8

What is an empirical formula?

Answer 8

The smallest ratio

Question 9

How do you do water of crystallisation?

Answer 9

1. Moles water lost
2. How many moles in the anhydrous salts
3. Do the ratio: mol anhydrous/ mol water

Question 10

Percentage yield=

Answer 10

(Actual/ theory) x 100

Question 11

Vol to use=

Answer 11

(Final conc/ initial conc) x vol required

Question 12

In an acid/ base titration, when do you know what indicator to use?

Answer 12

Methyl orange= yellow to red when adding acid to alkali

Phenolphthalein= red to colourless when acid to alkali

Question 13

What is spin pairing?

Answer 13

Electrons in the same orbital spin in opposite directions

Question 14

What is an ionic bond?

Answer 14

When ions are stuck together by electrostatic attraction.

Question 15

What behaviours do ions do?

Answer 15

1. Conduct electricity
2. High MP as strong electrostatic attraction
3. Soluble in water as polar

Question 16

What is a covalent bond?

Answer 16

Shares electrons

Question 17

Covalent bond properties

Answer 17

Fairly low MP and BP
Cant conduct electricity
Water insoluble

Question 18

How do properties of ionic lattice provide evidence for covalent bonding?

Answer 18

• high MP
• hard
• good thermal conductivity
• wont dissolve
• cant conduct electricity

Question 19

What makes the biggest angles and what makes the smallest?

Answer 19

LP/ LP biggest angles

BP/ BP smallest

Question 20

Tetrahedral bond angle

Answer 20

109.5°

Question 21

Trigonal pyrimidal

Answer 21

107°

• 1 LP
• 3 BP

Question 22

Bent shape

Answer 22

104. 5°
     - 2 LP
     - 2 BP

Question 23

Trigonal planar

Answer 23

120°

• 3 BP
• 0 LP

Question 24

Trigonal bipyrimidal

Answer 24

120° & 90°

• 5 BP
• 0 LP

Question 25

Octahedral

Answer 25

90° - 6 BP - 0 LP

Question 26

Periodic trends

Answer 26

- CD increased across the group | - first ionisation enthalpies decrease down the group and increase across a period

Question 27

What is the first ionisation enthalpy?

Answer 27

Energy needed to remove 1 electron from each atom in 1 mol gaseous atoms to form 1 mole gaseous +ve ions.

Question 28

What affects the size ionisation enthalpies?

Answer 28

1. Electron shielding 2. Atomic radius 3. Nuclear charge

Question 29

Group 2 reactions?

Answer 29

- with water to make hydroxides | - burn in oxygen to make oxides

Question 30

Thermal stability in group 2 carbonates

Answer 30

- increases down the group - carbonates large anions and can be made unstable by cations - makes the carbonate polarise itself - the greater the distortion the less stable the carbonate ion - large cations = less distortion as they have a lower CD. Larger cations are down the group

Question 31

What are salts?

Answer 31

Formed from positively charged cations and negative anions so the product is neutral

Question 32

Solubility rules?

Answer 32

- group 1 and ammonium salts soluble - nitrates soluble - group 7 soluble apart from silver halides - sulphates soluble - most hydroxides and carbonates insoluble

Question 33

How do you make insoluble salts?

Answer 33

1. Precipitation 2. Pick 2 solutions that contain the ions that you need 3. Filter

Question 34

Making soluble salts?

Answer 34

1. Pick an acid, plus an insoluble base 2. Metal oxide will dissolve as acid reacts. 3. Filter out the excess metal 4. Evaporation of water

Question 35

Making soluble salts using an alkali?

Answer 35

1. Need to add the correct amount of alkali to neutralise the acid. 2. Use a titration 3. Use an indicator 4. Evaporation of water

Question 36

What happens when electrons absorb energy

Answer 36

- get excited to a higher energy level - electrons release energy by dropping from a higher energy level - energy levels are quantised

Question 37

What is absorption spectra?

Answer 37

Dark lines coloured background - E= hv - electrons only absorb energy with correct frequency for the energy level - means frequencies of light missing

Question 38

What is emissions spectra?

Answer 38

Bright lines coloured background | - when electrons drop energy levels frequencies given out