Chemistry Paper 1 - GCSE - AQA

Ions

atoms that have lost or gained electrons and therefore have become charged

how is a positive ion formed?

when an atom loses electrons

How is a negative ion formed?

When an atom gains electrons

how are ions represented in diagrams?

through square brackets

ionic bonds properties

occurs between non-metals and metals through the transfer of electrons, electrostatic attraction between the negatively charge ion and the positively charged ion form the ionic bond

electrostatic forces in ionic lattices

Strong electrostatic forces between oppositely charged ions

Ionic lattices properties

between ions, between non-metals and metals,charged ions, giant structure

Melting/Boiling points and Ionic Lattices

high melting and boiling points as lots of energy is required to break the strong electrostatic forces between the oppositely charged ions

Conduction of electricity and Ionic Lattices

can't conduct electricity when solid as ions are unable to move and therefore can't carry a charge, can conduct electricity when molten or aqueous as ions are free to move and therefore are able to carry a charge

Covalent bonds occur between 2 or more ---------------------

non-metals

covalent bonds ---------------- electrons

share

Simple molecular structure properties

betwwen atoms, netural charge, covalent bonds,

Simple molecular structure conduction of electricity

don't conduct electricity as no free ions/electrons to carry the charge

Simple molecular structure boiling points

low melting and boiling poitns as weak intermolecular forces hence doesn't require much energy for forces to be broken

Giant covalent structure boiling points

high melting and oiling points as lots of energy neded to break strong covalent bonds

Giant covalent structure conduction of electrictiy (apart from graphite)

don't conduct electricity as no free ions or electrons to carry charge

Why is diamond hard?

Each carbon atom strongly bonded to 4 others. No carbon atoms can slide or move

Allotropes

different structural forms of the same element in the same state

Name 4 allotropes of carbon

diamond, graphite, fullerenes, graphene

Diamond boiling points

high melting and boiling pointsas lots of energy needed to break the strong covalent bonds

Why is graphite able to conduct electricity but diamond is not?

because graphite has sea of delocalised electrons which can carry charge throughout the structure however diamond has no delocalised electrons that can carry a caharge throught the structure

Why is graphite soft and slippery

because the layers can move/slide over eachother as there are weak intermolecular forces between the layers

Graphene properties

graphite is made up of lots of layers of graphene, multiple repeating hexagons, each carbon bonded to 3 other carbons making it really strong, each carbon atom donates 1 electron to pool of delocalised electrons , useful for making electronics as can conduct electricity

What is a fullerene?

Molecules of carbon or sheets of graphene shaped like closed tubes or hollow balls

what was the first fullerene discovered and how many C atoms did it contain?

Buckminster fullerene, 60 carbon atoms (C60)

Fullerene uses

Lubricants. can be used to deliver drugs to certain areas of body, makes industrial catalysts, electronics, strengthen other materials as hgh tensile strength but doesn't add weight

nanoscience is the study of...

particles between 1 and 100nm in size

Fractional Distillation

used to seperate 2 miscible liquids as they have different boiling points

Chromotography

A physical process used to determine what type of substances have been mixed together

Formula - Rf value for substance

distance travelled by substance/distance travelled by solvent

Name the subatomic particles

protons, neutrons, electrons

Neutron charge

0

Proton charge

1

Electron charge

-1

Why is the overall charge of an atom neutral?

As the number of protons equal the number of electrons the charges cancel each other out and neutrons are neutral

Isotopes

Atoms of the same element that have different numbers of neutrons but same amount of protons

Law of Conservation of Mass

atoms can't be created or destoryed - the total mass of the reactants = total mass of products

Ions

atoms that have gained or lost electrons

Element

A pure substance made of only one kind of atom

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Mixture

A combination of two or more substances that are not chemically combined

Who discovered the proton?

Rutherford

Who discovered the neutron

James Chadwick

Who discovered the electron

JJ Thomson

State the differences between the plum pudding and the nuclear model

plum pudding has dense mass in the centre nuclear mass spread evenly throughout

plum pudding has no empty space whereas the nuclear model is mainly empty space

Nuclear model has electrons orbiting nucleus whereas plum pudding model has electrons scattered randomly

inside positive cloud plum pudding has no nucleus whereas nuclear has nucleus

Ar stands for

relative atomic mass

Mr stands for

relative formula mass

how do you find the Ar of an element?

mass number

how do you find the Mr of a compound?

by adding up the Ar's of each element in it's ratio shown by the formula

1dm*3 = x cm*3

1000

formula for number of moles

mass/Mr

reactant mass = _____________________

product mass

% yield =

actual yield/ theoretical yield

% atom economy =

(RFM of desired product/sum of RFM for reactants)*100

Concentration =

amount of solute/volume

big numbers = __________

moles

little numbers = ____________

atoms

(gasses only) number of moles =

volume of gas/24

avogadro's constant =

6.022 x 10*23

Limiting reactant

the reactant used up first in a reaction

Excess reactant

the reactant left over in a reaction

Percentage yield

mass of product made compared to maximum amount of yield

Actual yield

mass of product made

Theoretical yield

mass of product that can be made

why is it not usually possible to get 100% yield

reaction may not be complete/reversible
other reactions may happen
some product may be lost

why should chemical manafacturer's only use reactants with high chemical yields?

helps conserve reduce energy waste
wastes as little energy as possible
helps reduce pollution
makes production more sustainable

End point

when alkali and acid have completely reacted

what is an acid-based indicator used to show in titrations?

the end point of a reaction

Atom economy

amount of reactants that end up as desired product

Why are reactions with a higher atom economy more stable?

fewer costs for waste treatments
conserves limited resources
uses fewer natural resources
saves energy

name two types of acid-based indicators that could be used when carrying out tirations?

Phenopthalein, methyl orange

phenopthalein colour change

pink (alkali) -> clear (neutral)

methyl orange colour change

yellow (alkali) -> orange (neutral)

concordant results

result within 0.1cm^3 of each other

Oxidised - in terms of Oxygen

When an element gains oxygen

Reduction - in terms of Oxygen

When an element loses oxygen

Metal + Oxygen

metal oxide

Metal + Water

metal hydroxide + hydrogen

Metal + Acid

Salt + Hydrogen

Nitric Acid as a salt

Nitrate

Nitric Acid Ion

NO3^-

Hydrochloric Acid as a salt

Chloride

Hydrochloric acid ion

Cl^-

Sulphuric acid as a salt

Sulphate

Sulphuric acid ion

SO4^2-

the reactivity series

a list of metals in order of reactivity

signs of chemical reaction

temperature change, bubbles, fizzing, colour change, explosions, production of hydrogen gas, moving, dissolving

What is an ore?

A rock that contains enough of a metal or a metal compound to make extracting the metal worthwhile

Order of Reactivity

Potassium, Sodium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Lead, Hydrogen, Copper, Silver, Gold

What are Carbon + Hydrogen used for?

to extract metals from metal compounds

Oxidation in terms of electrons

loss of electrons

Reduction

gain of electrons

What type of ion is created when electrons are lost?

+ive ion

Displacement reactions

When a more reactive metal will replace a less reactive metal from it's compound
- depends on reactivity series
- used to get metals on their own

Salt

compound formed when hydrogen in acid is wholly or partially replaced by a metal ion

when can salt be made?

from metals above hydrogen so it can be displaced

REQUIRED PRACTICAL FLASHCARDS

MAKING SOLUBLE SALTS FROM ACIDS

Acid + Base

salt + water (Neutralisation REACTION)

Method

1) using a measuring cylinder measure 20cm^3 of acid into the beaker
2) stand the beaker on a tripod and gauze and warm gently
3) add half a spatula of metal oxide powder into the acid and stir using the glass rod
4) keeping the acid warm but not boiling continue adding metal oxide until in excess
5) allow mixture to cool and then filter, discard residue
6) pour filtrate into evaporating basin and heat solution till volume is halved
7) remove from het and leave to crystallise

what is a base?

A substance that neutralises an acid