Chemistry GCSE Paper 1 Flashcards
How many different elements are in the periodic table?
100
What is a compound?
made from 2 or more elements which are combined chemically
What is a molecule?
formed when two atoms join together by chemical bonds
How can compounds be seperated into elements?
Chemical reactions
What is a mixture?
consists of two or more elements not chemically combined together
What is an atom?
The smallest particle
What is an Element?
made of only one type of atom
What are some examples of physical processes where mixtures can be separated?
Filtration crystallisation simple distillation fractional distillation chromotography
What does chromatography separate?
mixtures which include inks, dyes and colouring agents in food
What does filtration separate?
Separates a solid that can dissolve from one that can’t
What does evaporation separate?
separates a liquid and solid by boiling off the liquid
What does distillation separate?
Separates liquids with different boiling points
What does the plum pudding model suggest?
The atom is a ball of positive charge with negative electrons embedded in it
What did the alpha particle scattering experiment lead to?
led to the conclusion that the mass of an atom was concentrated at the centre and that the nucleus was charged. This nuclear model replaced the plum pudding model
What did James Chadwick experimental work suggest?
provided the evidence to show the existence of neutrons within the nucleus. This was about 20 years after the nucleus became and accepted scientific idea
Who adapted the nuclear model and what did it suggest?
Niels Bohr suggests that electrons orbit the nucleus at specific distances
What did later experiments lead to?
led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge. The name proton was given to these particles
What is the relative charge of a proton?
+1
What is the relative charge of the neutron?
0
What is the relative charge of the Electron?
-1
The number of electrons is equal to the number of what in the nucleus?
protons
What is the atomic number?
number of protons
What is the relative mass of protons?
1
What is the relative mass of neutrons?
1
What is the relative mass of electrons?
very small
What is the mass number?
sum of the protons and neutrons in an atom
What is an isotope?
element that has the same number of protons but a different number of neutrons
What are the elements in the periodic table ordered in?
ordered in atomic number
What are the columns in the periodic table known as?
Groups
Why is the table called the periodic table?
similar properties occur at regular intervals
Elements in the same group in the periodic table have the same number of what?
same number of electrons in their outer shell
How did people attempt to classify elements before the discovery of neutrons protons and electrons?
Arranging them in order of their atomic weight
What are the elements in Group 1 called?
Alkali metals
What does lithium do when it reacts with water?
floats, moves very quickly and fizzes
What does potassium do when it reacts with water?
floats, moves quickly, melts and fizzes gas may ignite with an orange flame
What does sodium do when it reacts with water?
floats, moves slowly and fizzes
Alkali metals generally become …………………. dense going down the group
less
What does caesium do when it reacts with water?
explodes almost instantly and breaks the glass container
How does lithium react when burnt?
orange flame
red flame
burnt fast
white solid left
How does sodium react when burnt?
orange flame
burnt slowly
melted
went silver
How does potassium react when burnt?
purple flame
burnt really fast
melted
Is the lithium oxide alkaline or acid?
Alkaline
Is the sodium oxide alkaline or acid?
Alkaline
Is the potassium oxide alkaline or acid?
Alkaline
Elements that react to form positive ions are …
metals
Elements that do not form positive ions are ….
non - metals
Majority of elements are …
metals
Where are metals found on the periodic table?
left and towards the bottom of the periodic table
Where are non metals found on the periodic table?
towards the right and top of the periodic table
What are the elements in group 0 called?
noble gases
Why are noble gases used for lights?
they don’t mix and are unreactive. They are also less dangerous then other gases
Why are noble gases unreactive?
have a dull outer shell of electrons
Do the atoms get smaller or bigger further down the group 0?
bigger
Does the boiling point increase or decrease the further down group 0?
Increases
Does the density of the atom decreases or increase as you go down group 0 and why?
increase because larger atoms take up more space so it makes it a stable element
What are the elements in Group 1 called?
Alkali metals
Does the reactivity of the elements in group 1 increase or decrease going down the group?
increase
What are the elements in Group 7 called?
halogens
What are halogens?
non metals and consist of molecules made of pair of atoms
When does ionic bonding occur?
Occurs in compounds formed from metals combined with non metals
When does covalent bonding occur?
occurs in most non metallic elements and in compounds of non metals
Where does metallic bonding occur?
occurs in metallic elements and alloys
What happens during ionic bonding?
metal atoms lose electrons to become positively charges and non metals gain electrons
What is an ionic compound?
Giant structure of ions
How are ionic compounds held together?
strong electrostactic forces of attraction between oppositely charged ion
What is covalent bonding?
when atoms share pairs of electrons
The bonds between atoms are…..
strong
What are diamond and silicon dioxide?
giant covalent structures
What are polymers?
covalently bonded substances which have very large molecules
What does metals consist of?
giant structures of atoms arranged in a regular pattern
What are the electrons like in the outer shell of a metal atom?
delocalised and are free to move through the whole structure
What does the sharing of delocalised electrons do?
gives rise to strong metallic bonds
What is giant tetrohedral?
each carbon bonded to four others
What is graphite?
giant hexagonal layer. each carbon makes only three bonds to other carbon
Why does diamond have a high melting point?
have strong covalent bond
giant covalent bond
Why does graphite conduct electricity?
it contain delocalised elctrons
carbon is only bonded to three other carbons
Why can graphite be used in the leads of pencils?
layers slip easy
weak intomellecular forces
How are gas particles arranged?
randomly placed and they move around freely
How are liquid particles arranged?
The particles are place near each other but not that close that they touch
How are solid particles arranged?
Placed in neat rows they vibrate against each other
What are the structures like for ionic compounds and how does this affects the melting point and boiling point?
regular structures in which they have strong electrostatic forces of attractions. They have high melting point and high boiling points because of the large amount of energy needed to break the many strong bonds
Which substances usually consist of small molecules?
gases
liquids
Which ones weaker intermolecular forces or covalent bonds?
intermolecularr
What are polymers like?
very large molecules. the atoms are linked to other atoms by strong covalent bonds. The intermollecular forces between molecules are relatively strong so are solid at room temperature
What is the state of giant covalent structures and what is the melting point like?
solids
very high melting points
What are the bonds like in giant covalent structures?
strong covalent bonds
What are the bonds in metals?
ginat structures with strong metallic bonding
How are the atoms arranged in pure metals?
arranged in layers which allows metals to be bent and shaped
What are alloys?
pure metals mixed with other metals
Why are metals good conductors of electricity?
declocalised electrons in the metal carry electrical charge through the metal
Whys are metals good conductors of thermal energy?
energy is transferred by the delocalised electrons
What is graphene?
a single layer of graphite
What are fullerenes?
molecules of carbon atoms with hollow shapes
What shape is the structures of fullerenes like?
hexagonal rings of carbon atoms
What are carbon nanotubes?
cylindrical fullerenes with very high length to diameter ratio
What does the proporties of carbon nanotubes make them useful for?
nanotechnology
electronics
materials
What is the relative formula mass of a compound?
sum of the relative atomic masses of the atoms in the numbers shown in the formula
What is the mass of one mole of a substance equal to?
relative formula mass
Chemical reactions take place in what?
solutions
What is the atom economy a measure of?
amount of starting materials that end up as useful products
What is the equation for the percentage atom economy?
relative formula mass of desired products / sum of relative formula masses of all reactants x 100
What can the concentration of solution be measured by?
mol/dm3
What does metals react to to produce metal oxides?
oxygen
What is oxidation?
when the metals gain oxygen
What is reduction?
when the metals lose oxygen
What is oxidation?
Loss of electrons
What is reduction?
gain of electrons
What can soluble salts be made from?
acids by reacting them with solid insoluble substances
What does acid produce in aqueous solutions?
hydrogen ions
What does aqueous solutions of alkalis contain?
hydroxide ions
What is a solution of pH7?
neutral
What are aqueous solutions of acids of less than 7?
alkalis
What are aqueous solutions of acids of greater than 7?
Acid
What happens to strong acids in aqueous solutions?
become completely ionised
What happens toweak acids in aqueous solutions?
only partially ionised
What does passing an electric current through eletrolytes do to the ions?
cause ions to move to the electrodes
What type of ions go to the cathode?
posotive
What type of ions go to the anode?
negative
When do you use electrolysis to extract a metal from a molten compound?
when metal is too reactive o be extracted by reduction with carbon
What is an endothermic reaction?
takes in energy from surrondings
What is an exothermic reaction?
one that transfers energy to the surronding
exothermic reaction?
energy released from forming new bonds is greater than the energy needed to break existing bonds
endothermic reaction
energy needed to break existing bonds is greater than the energy release from forming new bonds
What is the formula for hydrogen gas?
H2
What is the formula for nitrogen gas?
N2
What is the formula for ammonia?
NH3
What is the formula for sulfuric acid?
H2SO4
What is ionic bonding?
Transfer of electrons from a metal to a non metal
What is the properties if a giant ionic lattice?
High melting point
High boiling point
Only conducts electricity when molten or dissolved
What are the properties of a covalent bond?
Low melting point
Low boiling point
Do not conduct electricity
What are some giant covalent compounds?
Graphite
Diamond
What are some properties of giant covalent structure?
High melting and boiling point
Do not conduct electricity
Do not dissolve
What is diamonds structure?
Giant covalent
Carbon
Each carbon makes 4 bonds
What are the properties of diamond?
Hard
What is graphite structure?
Giant covalent
Carbon
Each carbon 3 bonds
What are some properties of graphite
Soft
Conducts electricity
What are some similarities between graphite and diamond?
Pure carbon
What are some differences between graphite and diamond?
Graphite 3 bonds and is soft
Diamond 4 bonds and hard
How do u work out concentration?
Amount / volume
What is a metal and acid going to give u?
Salt and hydrogen
What do u do before calculating the mass?
Balance the equation
What does a acid and metal oxide form?
Salt and water
What does an acid and metal hydroxide form?
Salt and water
What does an acid and metal base form?
Salt and water
What does a acid and metal carbonate form?
Salt and water and carbon dioxide
What is titration?
A technique used to find out how much of an acid is needed to neutralise and alkali or unknown concentration or vice versa
What is an ore?
A rock containing a metal or a metal compound
What is fractional distillation?
Where you separate crude oil into hydrocarbons with similar properties. The properties are called fractions
What are alkanes?
Hydrocarbon molecules that are saturated
