OCR AS level chemistry

C \= c double bond and two different groups attached to them.

What must molecules have to be an E/Z isomer?

It's isomerism commonly used to describe a special case of E/Z isomerism.

What is a cis - trans isomer?

One of the attached groups on each carbon atom of the double bond must have a hydrogen atom.

What makes a cis - trans isomer different from an E/Z isomer?

Is it E or Z if it is a cis isomer?

Z isomer - 'zame zide'

Is it E or Z if it is a trans isomer?

E isomer.

If the group of higher priority is on the same side then it is a Z isomer. If diagonally placed then it is an E isomer. (Proton numbers)

What are the cahn - ingold - prelog rules?

The higher the proton number, the higher the priority.

How do you assign priority?

Two steps.

How many steps are there to the Markowmikoffs rule with electrophillic addition?

A carbocation is formed. A primary and secondary carbocation. In the primary carbocation, the positive charge is on a carbon atom at the end of a chain.

What happens in the first step of Markowmikoffs rule?

The positive charge is on a carbon atom with two carbon chains attached.

What happens in the secondary carbocation?

Forms an aldehyde and water if it has been distilled.

What is formed when heating a primary alcohol under gentle reflux?

A carboxylic acid is formed with water.

What is formed when heating a primary alcohol under strong reflux?

Acidified potassium dichromate.

What reagent is used when preparing an aldehyde?

Acidified potassium dichromate in excess.

What reagent is used when preparing a carboxylic acid?

Distillation.

How do you separate an aldehyde from the mixture?

Ketone and water.

What happens when you oxidise a secondary alcohol under strong reflux?

No reaction, as the OH- group bonds are too strong to react.

What happens when you oxidise a tertiary alcohol under reflux?

Orange to green.

What colour change occurs when adding potassium dichromate?

Water is removed such as a H atom and the OH group.

What happens during the dehydration of alcohols?

SO4 2-

What is the formulae for sulphate?

PO4 3-

What is the formulae for phosphate?

OH-

What is the formulae for hydroxide?

H2SO4

What is the formulae for suphuric acid?

H3PO4

What is the formulae for phosphoric acid?

An element that has the same number of protons but different number of neutrons.

What is an isotope?

A charged atom.

What is an ion?

Mass of an isotope relative to 1/12th of the mass of an atom of carbon-12.

What is relative isotopic mass?

Mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12.

What is relative atomic mass?

The number of atoms of each element.

What is molecular formula?

The simplest whole number ratio of atoms of each element within a compound.

What is empirical formula?

Compares the mass of a molecule with the mass of an atom of carbon-12.

What is relative molecular mass?

Compares the mass of a formula with the mass of an atom of carbon-12.

What is relative formula mass?

PV \= nRT

What is the ideal gas equation?

Pascal

What is the unit for pressure in the ideal gas equation?

Metres cubed

What is the unit for volume in the ideal gas equation?

Kelvin

What is the unit for temperate in the ideal gas equation?

Add 273.

How do you work out temperature from degrees Celsius to Kelvin?

When all H+ ions are released when dissolved in a solution and it is fully disassociated.

What is a strong acid?

When some H+ ions are released when dissolved in a solution and they are partly disassociated.

What is a weak acid?

A base neutralises an acid to form a salt. It does this by replacing the H+ ion with a metal ion.

What is a base?

A base that dissolves in water to release OH- ions.

What is an alkali?

It's the electrostatic attraction between positive and negative ions.

What is ionic bonding?

Multiple ions attracting oppositely charged ions.

What is a giant ionic lattice?

High boiling point and melting point, to overcome the strong forces. Ions with bigger ionic charges have bigger melting and boiling points.

What are the boiling points of ionic lattices?

Dissolve in polar compounds such as water.

What is the solubility of ionic lattices?

Doesn't conduct when solid because the ions are fixed and can't carry an electrical charge. Conducts when in molten and when dissolved in a solution because the ions are free to move and conduct an electrical charge.

What is the electrical conductivity?

Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atom.

What is a covalent bond?

Lone pairs repel more than bond pairs.

What is the electron repulsion theory?

Tetrahedral

What is the shape of a molecule with 4 bonded pairs and 0 lone pairs?

109.5

What is the bond angle of a tetrahedral?

Pyramidal

What is the shape of a molecule with 3 bond pairs and 1 lone pair?

107

What is the bond angle of a pyramidal molecule?

Non - linear

What is the shape of a molecule with 2 lone and bond pairs?

104.5

What is the bond angle of a non - linear molecule?

Linear

What is the name of a molecule with 2 bond pairs?

180

What is the bond angle of a linear molecule?

Triganol planar

What is the shape of a molecule with 3 bond pairs?

120

What is the bond angle of a triganol planar molecule?

Octahedral

What is the shape of a molecule with 6 bond pairs?

90

What is the bond angle of a octahedral molecule?

By the Pauling Electronegstivity Scale

How is electronegstivity measured?

Increase

Does electronegativity increase or decrease across the periodic table?

Decreases

Does the atomic radius increase or decrease across the periodic table?

When two molecules share a shared pair of electrons equally, it's symmetrical and they have similar electronegativity.

What are non - polar bonds?

Where the two molecules don't share the shared pair of electrons equally, they're asymmetrical and have different electronegativities.

What are polar bonds?

Pure covalent bond.

What are the bonds in non - polar bonds?

Polar covalent bonds.

What are the bonds in polar bonds?

Water.

An example of a polar molecule?

The two dipoles act in different directions.

What do polar molecules dipoles do?

CO2

What is an example of non - polar molecules?

The two dipoles act in opposite directions and exactly oppose each other. The dipoles cancel and the overall dipole is zero.

What do non - polar molecules do?

London forces, permanent dipole - dipole forces, and hydrogen bonding.

What are the three types of Intermolecular formulas?

Movement of electrons produces a changing dipole in a molecule. Any moment, an instantaneous dipole will exist. This induces a dipole in a neighbouring molecule.

How are induced dipole - dipole interactions created?

Temporary

Are induced dipole dipole interactions permanent or temporary?

The more electrons, means the larger the instantaneous dipole and the greater the dipoles and the stronger the attractive forces between molecules.

What determines the strength of London forces?

Between permanent dipoles in different polar molecules.

What are permanent dipole - dipole interactions?

All

Are induced dipole - dipole molecules in all or only some molecules?

Polar.

Are permanent dipole - dipole interactions in polar or non - polar molecules?

Low melting and boiling points.

What is the melting and boiling point of simple molecular substances?

Only the weak molecular forces.

Do the covalent bonds or weak molecular forces break in simple molecule substances when heated or melted?

Split into polar and non polar substances.

What is the solubility of simple molecular substances?

Soluble in non - polar substances but insoluble in polar substances.

What is the solubility of non - polar simple molecular substances?

Soluble in polar molecules and some compounds such as ethanol contain polar and non polar parts in their structure and can dissolve in both polar and non polar substances.

What is the solubility of polar simple molecular substances?

Non conductors as they have no mobile charged particles.

What is the electrical conductivity of simple molecular substances?

Special type of permanent dipole - dipole interactions between molecules containing an atom with a lone pair, and a hydrogen atom attached to O, N or F.

What are hydrogen bonds?

Solid is less dense than liquid, and they have relatively high boiling and melting points.

What are the two anomalous properties of water?

Hydrogen bonds hold water molecules apart in an open lattice structure, the water molecules in ice are further apart than water, so solid ice is less dense than liquid water and floats.

Why is solid ice less dense than liquid water?

A repeating, periodic pattern.

What is periodicity?

Measures how easily an atom loses electrons to form positive ions.

What is ionisation energy?

Energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions.

What is the first ionisation energy?

Atomic radius, nuclear charge and electron shielding.

What are the three factors affecting ionisation energy?

Distance between the nucleus and the outer electrons.

What is the atomic radius?

A large jump of more than 4 times.

What indicates that the last electron of one shell has been removed and another has been affected?

Increases

What is the trend of atomic radius down a group?

Increases

What is the trend of electron shielding down a group?

Stays the same so ineffective.

What is the trend of nuclear charge down a group?

Decrease

What is the trend of first ionisation energies down a group?

Increase

What is the trend of atomic radius across a period?

Increases

What is the trend of nuclear charge across a period?

Stays the same.

What is the trend of electron shielding across a period?