Exam questions Flashcards
Meaning of electronegativity
The ability of an atom to attract a pair of electrons in a covalent bond
How permanent dipole-dipole forces arise
The difference in electronegativity leads to bond polarity
What is meant by the term ionic lattice
Repeating pattern of oppositely charged ions
Why some molecules are polar
Molecule is non-symmetrical
Dipoles do not cancel out
What is a base
Substance which readily accepts h+ ions from an acid
What is an alkali
Releases OH- ions into an aqueous solution
What is ionic bonding
electrostatic attraction between oppositely charged ions
Anomalous properties of water
Ice lighter than water - open lattice in ice
HMP/BP - Strength of hydrogen bonds
High surface tension - the strength of H bonds spread across the surface
Properties of graphite
Giant covalent lattice
Good conductor - delocalised ELECTRONS
HBP - covalent bonds have to be broken
Soft - Van der waal forces
why ionic compounds cannot conduct when solid
Ions fixed in a lattice
Bond of Cl2 and C
Cl2 - Van der vaals
C - covalent bond
Why lalala has a lower first ionisation energy than lalala
Increase in energy shells as we go down
Increased shielding
Nuclear attraction decreases
Why second ionisation energy of oxygen has greater value than 1st ionisation energy
o+ ion smaller than O atom
More protons
Less electron-electron
Why 1st ionisation energies show a general increase across period 2
Increase in nuclear charge
The greater attraction between an electron and positive nucleus. more energy needed to break bond
Why first ionisation energy of lalala is less than that of lalala
lalala electron being removed at a higher energy shell
How to improve the standard situation practical
Rinse the weighing boat into flask after transferring solid
re-weigh weighing boat for precise mass
Dissolve solid in a beaker of water before transferring to to volumetric flask
Use a funnel to add solid
Use a pipette to add last few drops of distilled water
What would happen if there is more of the powder thingy than expected in standard solution
Decrease mean titre volume
concentration higher
less would be needed to neutralise solution
What does (V) represent in chloric(V) acid?
the oxidation number of chlorine
Suggest why the enthalpy change of formation of C6H12O6 cannot be determined directly
Activation energy too high
Use of alcohol
Solvent
Manufacture of Ester
The reaction between nitrogen and oxygen in a car engine does not reach a dynamic equilibrium
Not a closed
How does a reaction reach dynamic equilibrium
Rate of forward reaction slows down and rate of backward reaction speeds up
Útil rate of forward = rate of backwards
How does infrared spec identify NO
Identifies functional group
Each pollutant has different spectrum
Can measure concentration of NO
What is wrong with HCL
Forms acid rain
Corrosive
