Salters A level Chemistry exam questions

stages of mass spectroscopy

• Ionisation: sample turns into postively charged ions

• Acceleration: ions are accelerated by an electric field so they all have the same k.e

• Drift: enters a region with no electric field

what is a beta particle

a free electron

Why did Mendeleevs decide an element was yet to be discovered at this position in this arrangement

Without gaps the properties of elements wouldn't match

What was Mendeleev's table based off of?

It was based off of atomic weight as well as the properties of adjacent elements

which part of the electronic structure of an element shows the period the element is in?

number of occupied shells

Which part of the table shows the group the element is in?

number of electrons in outer shell

Why can an increase in entropy happen?

when there is an increase in molecules means there are more possible arrangments that a molecule can make, also if particles change from a liquid to gas bc of more k.e

How do you count the carbons on a skeletal structure

You count the corners for each carbon

Name the process used in the oil industry to convert chain alkanes to cyclic alkanes?

Reforming

What is bond enthalpy?

Bond enthalpy is the energy required to break one mole of a bond and can differ for the same bonds in different molecules

Explain why an atomic emission spectrum is unique to a particular element

energy absorbed causes electrons to go to promoted energy levels, and drop back emitting energy in the form of light. Energy levels are quantised and energy is proportional to the frequency of hf/e. Spectra are unique because different elements have different gaps between energy levels

name the process used to seperate the mixture of compounds in crude oil

Fractional distillation

describe a simple molecule to explain the function of a heterogenous catalyst

the reactants are adsorbed onto the catalyst. Intramolecular bonds in reactants weaken and break. New bonds form, and product diffuses off of catalyst

suggest why one mole of aluminium hydroxide neutralises more acid than one mole of magnesium hydroxide?

as aluminium can bond to more -OH molecules which neutralises more H+ ions

what is the structure of silicon

covalent network

what is charge density

the amount of electric charge that concentrated in a given volume

What is polarising power?

The ability of a cation to distort the electron cloud of an anion, making ionic bonds weaken, making it more easier to decompose (less thermally stable)

what is cracking?

cracking is the process of breaking down larger molecules into smaller hydrocarbons (alkanes and alkenes)