Things I Dont Know

Question 1

Explain why there is an increase in the first ionisation energy

Answer 1

The number of protons is increasing

Question 2

Explain fully the large increase between the first and second ionisation energies

Answer 2

The second ionisation energy involves the removal of an electron from an electron shell that is closer to the nucleus, so the second electron is less screened, so is more strongly attracted ti the nucleus

Question 3

State what is meant by the term electronegativity

Answer 3

The attraction an atom has for the electrons in its bond

Question 4

Suggest what would need to be done to the sample to allow the concentration to be determined

Answer 4

Use less sample

Question 5

Name Ca2+ (CH3CH2COO-)2

Answer 5

Calciumpropanoate

Question 6

Suggest a reason why the method shown is the preferred industrial route

Answer 6

It has 100% atom economy

Question 7

Describe the term used to describe this part of the molecule SO3-Na+

Answer 7

Hydrophylic

Question 8

Explain the decrease in covalent radius going from nitrogen to fluorine

Answer 8

Increasing number of protons

Question 9

State what is meant by the term first ionisation e Gerry

Answer 9

The energy required to change one mole of electrons into one mole of gaseous atoms

Question 10

Explain how hydrogen bonding arises

Answer 10

Between molecules that have hydrogen bonded to Nitrogen, Oxygen, Fluorine

Question 11

Explain fully why increasing temperature increases the rate of reaction

Answer 11

Increases the number of particles with energy equal to or greater then the activation energy. So more successful collisions occur

Question 12

State how emulsifiers are made of edible oils

Answer 12

By reacting with glycerol

Question 13

Suggest why potassium dichromate must be acidified

Answer 13

To provide hydrogen ions

Question 14

Colour change of acidified potassium dichromate

Answer 14

Orange to green

Question 15

Essential amino acids

Answer 15

Can’t be made in the body

Question 16

Name the type of reaction that takes place when amino acids join to form proteins

Answer 16

Condensation

Question 17

Explain fully what happens to the enzyme structure to cause this reduction in activity

Answer 17

The enzyme changes shape, hydrogen bonds are broken

Question 18

Explain why antioxidants are added to food

Answer 18

To stop food acquiring a rancid flavour

Question 19

Explain fluky why vitamin C is soluble in water (OH)

Answer 19

Vitamin C can for hydrogen bonds due to its hydroxyl groups, so it is polar, water is also polar, as like dissolves like vitamin C dissolves in water

Question 20

Sate the term used to describe the type of bond in hydrogen fluoride

Answer 20

Polar covalent

Question 21

State the term used to describe the structure of solid ionic compounds like lithium nitride

Answer 21

Ionic lattice

Question 22

What is a free radical

Answer 22

Atoms with unpaired electrons

Question 23

Name the type of reaction that joins 2 free radicals together

Answer 23

Termination

Question 24

State why a small shock or bump can cause nitroglycerin to react

Answer 24

The shock provides the activation energy

Question 25

State what is meant by a standard solution

Answer 25

A solution of an accurately known concentration

Question 26

State a disadvantage of industrial processes that involves reactions that are highly exothermic

Answer 26

Require heat to be removed

Question 27

Explain how LDF’s arise

Answer 27

Formed as a result of the electrostatic attraction between temporary dipoles and induced dipoles caused by the random moment of electrons in atoms and molecules

Question 28

Name the family of compounds to which enzymes belong

Answer 28

Proteins

Question 29

State the systematic name for isoprene

Answer 29

2-methylbuta-1,3-diene

Question 30

Explain fully why there is and increase in the 5th and 6th ionisation energies

Answer 30

The 6th ionisation energy involves removing an electron from a shell that is closer to the nucleus, so there is less shielding so more attraction

Question 31

Explain fully why the ionic radius of phosphorus is greater then the ionic radius of aluminium

Answer 31

Aluminium forms Al3+ and phosphorus forms P3-, aluminium ion has 1 less energy level than phosphorus ion

Question 32

Further oxidation of ethanal can form another product, name this product

Answer 32

ethanoic acid

Question 33

What is the difference between bond enthalpy and mean bond enthalpy

Answer 33

Mean bond enthalpy must relate to an average energy and to a number of compounds and bond enthalpy must relate to one compound

Question 34

Enthalpy of combustion equation

Answer 34

Delta H = Eh/n

Question 35

Explain why students used deionised water

Answer 35

Water may contain chlorine ions

Question 36

Explain fully in terms of structure and bonding why silicon nitride has a high melting point

Answer 36

Is covalent network and covalent bonds are broken

Question 37

Explain fully what can happen to 3-methylbutanal that will cause the olive oil to develop an unpleasant taste

Answer 37

It will react with oxygen forming a carboxylic acid

Question 38

State how free radical scavengers prevent further chain reactions

Answer 38

They can react with free radicals forming stable compounds

Question 39

Explain why step one is described as a condensation reaction

Answer 39

2 molecules are joining together with the loss of water

Question 40

Explain how free radicals are formed

Answer 40

Bond breaking by UV light