Things I Dont Know Flashcards
Explain why there is an increase in the first ionisation energy
The number of protons is increasing
Explain fully the large increase between the first and second ionisation energies
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
State what is meant by the term electronegativity
The attraction an atom has for the electrons in its bond
Suggest what would need to be done to the sample to allow the concentration to be determined
Use less sample
Name Ca2+ (CH3CH2COO-)2
Calciumpropanoate
Suggest a reason why the method shown is the preferred industrial route
It has 100% atom economy
Describe the term used to describe this part of the molecule SO3-Na+
Hydrophylic
Explain the decrease in covalent radius going from nitrogen to fluorine
Increasing number of protons
State what is meant by the term first ionisation e Gerry
The energy required to change one mole of electrons into one mole of gaseous atoms
Explain how hydrogen bonding arises
Between molecules that have hydrogen bonded to Nitrogen, Oxygen, Fluorine
Explain fully why increasing temperature increases the rate of reaction
Increases the number of particles with energy equal to or greater then the activation energy. So more successful collisions occur
State how emulsifiers are made of edible oils
By reacting with glycerol
Suggest why potassium dichromate must be acidified
To provide hydrogen ions
Colour change of acidified potassium dichromate
Orange to green
Essential amino acids
Can’t be made in the body
Name the type of reaction that takes place when amino acids join to form proteins
Condensation
Explain fully what happens to the enzyme structure to cause this reduction in activity
The enzyme changes shape, hydrogen bonds are broken
Explain why antioxidants are added to food
To stop food acquiring a rancid flavour
Explain fluky why vitamin C is soluble in water (OH)
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
Sate the term used to describe the type of bond in hydrogen fluoride
Polar covalent
State the term used to describe the structure of solid ionic compounds like lithium nitride
Ionic lattice
What is a free radical
Atoms with unpaired electrons
Name the type of reaction that joins 2 free radicals together
Termination
State why a small shock or bump can cause nitroglycerin to react
The shock provides the activation energy
State what is meant by a standard solution
A solution of an accurately known concentration
State a disadvantage of industrial processes that involves reactions that are highly exothermic
Require heat to be removed
Explain how LDF’s arise
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
Name the family of compounds to which enzymes belong
Proteins
State the systematic name for isoprene
2-methylbuta-1,3-diene
Explain fully why there is and increase in the 5th and 6th ionisation energies
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
Explain fully why the ionic radius of phosphorus is greater then the ionic radius of aluminium
Aluminium forms Al3+ and phosphorus forms P3-, aluminium ion has 1 less energy level than phosphorus ion
Further oxidation of ethanal can form another product, name this product
ethanoic acid
What is the difference between bond enthalpy and mean bond enthalpy
Mean bond enthalpy must relate to an average energy and to a number of compounds and bond enthalpy must relate to one compound
Enthalpy of combustion equation
Delta H = Eh/n
Explain why students used deionised water
Water may contain chlorine ions
Explain fully in terms of structure and bonding why silicon nitride has a high melting point
Is covalent network and covalent bonds are broken
Explain fully what can happen to 3-methylbutanal that will cause the olive oil to develop an unpleasant taste
It will react with oxygen forming a carboxylic acid
State how free radical scavengers prevent further chain reactions
They can react with free radicals forming stable compounds
Explain why step one is described as a condensation reaction
2 molecules are joining together with the loss of water
Explain how free radicals are formed
Bond breaking by UV light
