Chemistry Paper 1 Topics Flashcards
What is a mass number?
The mass number is the total number of protons and neutrons in atoms
What is an atomic number?
The atomic number is the total number of protons in an atom
What is the relative mass of a proton?
The relative mass of a proton is 1
What is the relative mass of a neutron?
The relative mass of a neutron is 1
What is the relative mass of an electron?
The relative mass of an electron is very small (1/2000)
What is the relative charge of a proton?
The relative charge of a proton is +1
What is the relative charge of a neutron?
The relative charge of a neutron is 0
What is the relative charge of an electron?
The relative charge of an electron is -1
What is an element?
An element is a substance made up of atoms with the same atomic number
What is an isotope?
Isotopes are atoms with the same number of protons but different numbers of neutrons
What is a compound?
A compound is a substance formed from two or more elements chemically combined together
What is a molecule?
A molecule is a particle containing two or more non-metal atoms bonded covalently
What did the plum pudding model look like?
The plum pudding model was a ball of positive charge containing small negative electrons
What did the nuclear model look like?
The nuclear model showed that mass is concentrated in a positive nucleus with a cloud of electrons
What were the three conclusions of the alpha scattering experiment?
The three conclusions of the alpha scattering experiment were:
- the nucleus is mostly empty space
- the nucleus is dense
- the nucleus is positive
What did the Bohr model show?
The Bohr model showed electrons orbiting a nucleus in fixed shells
What did James Chadwick provide evidence for?
James Chadwick provided evidence that neutrons are neutral particles found in the nucleus
How did Mendeleev order the elements in the periodic table?
Mendeleev ordered the elements in the periodic table by their properties
Why did Mendeleev leave gaps in his periodic table?
Mendeleev left gaps in his periodic table for elements to be placed there when they are later discovered, and also so groups are kept together
What did the discovery of isotopes conclude?
The discovery of isotopes explained why elements cannot be strictly ordered by atomic weight
What does the group number on a periodic table mean?
The group number shows the number of electrons in atom’s outer shell
What does the periodic number on a periodic table mean?
The periodic number shows the number of shells with electrons in
When are metals most reactive?
Metals are most reactive when they lose electrons more easily
Where are metals most reactive on the periodic table?
Metals are most reactive towards the bottom left of the periodic table
How do metals get full outer shells?
Metals get full outer shells by losing electrons
How do non-metals get full outer shells?
Non-metals get full outer shells by gaining or sharing electrons
When are non-metals most reactive?
Non-metals are more reactive when they gain electrons more easily
Where on the periodic table are non-metals most reactive?
Non-metals are most reactive towards the top right of the periodic table
What are the properties of metals?
The properties of metals are that they are shiny, strong but malleable, have high boiling and melting points, are good electrical and thermal conductors
What are the properties of non-metals?
The properties of non-metals are that they are dull, brittle, have low melting and boiling points, are poor conductors
What are the properties of the transition metals found in the centre of the periodic table?
Transition metals have multiple ions, form colourful compounds, can be good catalysts
What happens to alkali metals as you go down the group?
As you go down the group of alkali metals, reactivity increases, melting and boiling point decreases and relative atomic mass increases
What are the properties of alkali metals?
Alkali metals are more reactive than other metals, are less dense and softer than other metals and has lower melting points
Metal + Water > ?
Metal + Water > Metal hydroxide + hydrogen
Metal + Chlorine > ?
Metal + Chlorine > Metal chloride
Metal + Oxygen > ?
Metal + Oxygen > Metal oxide
What happens to a reaction with water as the reactivity increases?
The reaction becomes more vigorous and explosive as a reaction with water increases
What is the appearance of fluorine?
Fluorine appears as a yellow gas
What is the appearance of chlorine?
Chlorine appears as a dense green gas
What is the appearance of bromine?
Bromine appears as a volatile red-brown liquid
What is the appearance of iodine?
Iodine appears as a dark grey solid or purple vapour
What happens as you go down group 7?
As you go down group 7, reactivity decreases, melting and boiling points increase and the relative mass increases
What do halogens exist as?
Halogens exist as diatomic molecules - two atoms joined by a covalent bond
What are ions?
Ions are charged particles made when electrons are transferred
What do metals do in order to get a full outer shell? What charge does this make them?
Metals lose electrons to form positive +1 ions if in group 1, and positive +2 ions if in group 2
What do non-metals do in order to get a full outer shell? What charge does this make them?
Non-metals gain electrons to form negative -1 ions if in group 7, and negative -2 ions in group 6
What is ionic bonding?
Ionic bonding is the electrostatic attraction between oppositely charged ions. Ionic bonding occurs between positive metal ions and negative non-metal ions
What are the properties of ionic compounds?
The properties of ionic compounds are:
- Giant ionic lattice structure
- High melting and boiling points
- Conducts electricity only when molten or dissolved - so ions are free to move and carry electric charge
What are the limitations of the 3D model of compounds?
The 3d model is not to scale, there are gaps between ions and only the outer layer of the compound can be seen
What is a covalent bond?
A covalent bond is a shared pair of electrons between two non-metal atoms
What do molecular formulas show eg NH3
Molecular formulas show you how many atoms of each element are in a compound
What are the negatives of using a dot and cross diagram?
Dot and cross diagrams don’t show the relative size of atoms or their arrangement in space
What are the negatives of ball and stick diagrams?
Ball and stick diagrams don’t show which atoms the electrons in the bonds come from
What are the properties of simple molecular substances?
The properties of simple molecular substances include low melting and boiling points (mostly gas and liquid at room temperature), and doesn’t conduct electricity as there are no charged particles
What are the properties of diamond?
Diamond is very hard, has a high melting point, doesn’t conduct electricity
What are the properties of graphite?
Graphite is soft, slippery, have high melting points and can conduct electricity and thermal energy
What are the properties of graphene?
Graphene is strong, light and conducts electricity
What are the properties of fullerenes?
Fullerenes have hollow shapes and rings of atoms
What are the features of metallic bonding?
Metallic bonding is a giant regular structure, held together by strong electrostatic attractions between metal atoms, has delocalised outer shell electrons that are free to move
What are the properties of metals?
Metals:
- High melting and boiling points - lots of energy needed to overcome strong metallic bonds
- Good thermal conductors - energy transferred by delocalised electrons
- Good electrical conductors - delocalised electrons carry a charge
- Soft and malleable - layers in metals slide over each other
What are alloys?
Alloys are a mixture of metal and at least one other element. They are harder than pure metals and can’t slide over each other due to the new elements
What are the characteristics of solids? (arrangement, movement, closeness)
Solids have a regular arrangement, vibrate in fixed positions, and are very close together
What are the characteristics of liquids? (arrangement, movement, closeness)
Liquids have a random arrangement, move (flow) around each other and are close together
What are the characteristics of gases? (arrangement, movement, closeness)
Gases are randomly arranged, moves quickly in all directions and are far apart
What are the problems with particle theory? (diagrams)
Particle theory does not show forces and portrays particles as solid spheres which are incorrect
What is the change of state from solid to liquid?
The change from solid to liquid is melting
What is the change of state from liquid to gas?
The change from liquid to gas is evaporating/boiling
What is the change of state from gas to liquid?
The change from gas to liquid is condensation
What is the change of state from liquid to solid?
The change from liquid to solid is freezing
What is the process when a substance is heated up?
When a substance is heated up, particles gain energy, forces between particles weaken and break free from their position
What is the process when a substance condenses/freezes?
Substance cools down > particles lose energy > forces between particles form > particles held in position
How do you find relative formula mass?
Relative formula mass = adding all the atomic masses together
How do you find the percentage mass of an element in a compound?
Percentage mass of an element in a compound = (atomic number x number of atoms in that element) divided by relative formula mass of the compound, x 100
What does avogrado constant state?
Avogrado constant - one mole = 6.023 x 10^23 particles of a solution
How do you calculate the number of moles?
Number of moles = Mass divided by relative formula mass
What does conservation of mass state?
Conservation of mass = no atoms are created or destroyed in a chemical reaction, so the total masses of reactants and products are the same
What does it mean if there is a decrease in mass after a reaction?
Decrease in mass = gas is made during the reaction that has escaped
What does it mean if there is an increase in mass after a reaction?
Increase in mass = gas is a reactant so its mass is added to the mass in the vessel where the reaction is taking place
How do you balance equations using masses?
Balancing equations using masses:
1) . mass divided by rfm to find the number of moles of each substance
2) . divide the number of moles by the smallest number of mole
3) . if results aren’t whole numbers, multiply them by the same number so that they are whole
What is a limiting reactant?
A limiting reactant is a reactant that gets completely used up in a reaction, so limits the amount of product formed
How do you find the volume of gas?
Volume of gas = (mass divided by rfm) x 24
What is concentration?
Concentration is the amount of substance dissolved in a certain volume of solution
What happens to the concentration when you increase the amount of solute?
Increasing amount of solute increases the concentration
What happens to the concentration when you increase the volume of solvent?
Increasing volume of solvent = concentration decreases
How do you find concentration if you know mass and volume?
Concentration (g/dm^3) = mass of solute divided by the volume of solvent
How do you find the concentration if you know moles and volume?
Concentration (mol/dm^3) = the number of moles of solute divided by the volume of solvent
How do you use titration to calculate concentration?
Using titrations to calculate concentrations:
1) . known concentration x volume to find moles of reactant 1
2) . find moles of reactant 2 using equations
3) . moles of reactant 2 divided by the volume to get its concentration
What factors affect yield?
Factors that affect yield:
- Reaction is not completed
- Some reactants used up by side reactions
- Some products lost when separated from the reaction mixture
What are the features of the metals at the top third of the reactivity series? (K,Na,Ca,Mg,Al)
Metals at the top of the reactivity series have explosive reactions and are extracted from their molten compounds using electrolysis
What are the features of the metals at the centre of the reactivity series (Zn, Fe, Tn, Le)
Metals at the centre of the reactivity series have moderate reactions and are extracted from their oxides by reduction of carbon
Metal + Oxygen >?
Metal + Oxygen > Metal Oxide
Metal + Acid > ?
Metal + Acid > Salt + Hydrogen
Metal + water > ?
Metal + water > Metal Hydroxide + Hydrogen
How does the speed of reaction affect the production of hydrogen bubbles?
Faster reaction = more production of hydrogen bubbles
What is a displacement reaction?
A displacement reaction is when a more reactive element displaces a less reactive element from its compound
What is oxidation?
Oxidation = loss of electrons, gain of oxygen
What is reduction?
Reduction = gain of electrons, loss of oxygen
What is a redox reaction?
Redox reaction = where one substance in a reaction is reduced and another is oxidised
What materials do you use to measure pH?
Measure pH with universal indicator and pH probe
What is the neutralisation reaction?
Neutralisation = Acid + base > salt + water (H+ + OH- > H20)
Acid + Metal Carbonate > ?
Acid + Metal carbonate > Salt + Water + Carbon Dioxide
Acid + Metal Oxide > ?
Acid + metal Oxide > Salt + Water
Acid + Metal Hydroxide > ?
Acid + Metal Hydroxide > Salt + Water
How are soluble salts made?
Soluble salts are made by adding metals or insoluble metal compounds to acids. Excess solid is filtered off and the remaining salt solution is crystalised
How do strong acids react in water?
Strong acids completely ionise in water to produce hydrogen ions
How do weak acids react in water?
Weak acids only partially ionise in water to produce hydrogen ions
Describe the method to make soluble salts
Method to making soluble salts:
1) . warm dilute acid with Bunsen burner
2) . add insoluble metal or oxide ( that contains the correct ions for the soluble salt )
3) . mix solution
4) . filter off excess solid using filter paper in funnel
5) . heat solution to evaporate some of it
6) . salt will crystallise. dry salts
Describe the method of titration
Titration:
1) . use funnel to add acid to buriette
2) . take initial reading
3) . slowly add acid to alkali
4) . add acid drop by drop towards the end point
5) . indicator will change colour once alkali is neutralised
6) . repeat
Where do positive ions move to in electrolysis?
In electrolysis, positive ions move to the cathode as the cathode is negative. The positive metals are reduced, where they gain electrons
Where do negative ions move to in electrolysis?
In electrolysis, negative ions move to the anode as the anode is positive. The negative non-metals are oxidised, where they lose electrons
Describe the extraction of alumnium oxide
Molten Aluminium oxide is mixed with cryolite. The Al3+ ions move to the cathode and are reduced (Al3+ + 3e- > Al). The negative O2- ions move to the anode where they are oxidised (2O2- > O2 + 4e-)
What is produced at the cathode if the metal is less reactive than H2?
If the metal is less reactive than H2, the metal will be produced at the cathode. If the metal is more reactive than H2, then H2 will then be produced at the cathode
What is produced at the anode in the electrolysis of aqueous ionic compounds?
O2 and H20 is produced at the anode (if no halide ions are present) - Halogen is produced at anode if halide ions are present eg Br-, Cl-
What happens in endothermic reactions?
In endothermic reactions, energy is taken in from the surroundings eg thermal decomposition. It can be used for ice packs.
What happens in exothermic reactions?
In exothermic reactions, energy is released from the surroundings
What are examples of exothermic reactions?
Examples of exothermic reactions include combustion and neutralisation
What is activation energy?
Activation energy is the minimum amount of energy needed for reactants to react
Which reaction breaks bonds?
Endothermic reactions break bonds when energy is supplied
Which reaction forms bonds?
Exothermic reactions form bonds and release energy
When investigating temperature change in a beaker, what are the independent and dependant variables?
Independant variable = concentration / mass of reactants
Dependant variable = temperature change
What are the properties of transition metals?
Transition metals are hard, dense and less reactive than alkali metals
They form ions with different positive charges, can form colourful compounds and are often used as catalysts
What are the properties of alkali metals?
Alkali metals reactivity increases down the group, reacts vigorously with water - hydrogen gas is given off and metal hydroxide is produced. (The metal floats on the surface, and enough energy is released to melt the metal)
What happens when lithium reacts with water?
When lithium reacts with water, it fizzes and lithium floats and becomes smaller
What happens when sodium reacts with water?
When sodium reacts with water, sodium melts to form a ball, fizzes hydrogen produced burns with orange flame
What happens when potassium reacts with water?
When potassium reacts with water, the metal melts and floats, hydrogen gas ignites instantly, metal sparks a lilac flame
What happens to hydroxides formed in reactions?
Hydroxides formed in reactions dissolve in water to form alkaline solutions
What holds together an ionic lattice?
Electrostatic forces hold together an ionic lattice
What are examples of giant covalent structures?
Diamond, graphite and silicon dioxide are examples of giant covalent structures
What happens during the freezing of a liquid?
During freezing, water molecules lose energy, move around less and form a fixed lattice
Why do polymers melt easily at room temperature despite being solid?
Polymers melt easily at room temperature despite being solid because their size means they have many intermolecular interactions, and their intermolecular forces are weaker than their chemical bonds
How can we reduce uncertainty in an experiment?
Reduce uncertainty by repeating an experiment and finding an average
What are the two factors that makes yield less than 100%?
Side reactions and incomplete reactions guarantee a yield below 100%
How do you calculate atom economy?
Atom economy = (Mr of desired products) / (Total relative mass of reactants) x 100
What makes a metal more reactive?
A metal that can form a positive ion easily are more reactive
What is a spectator ion?
A spectator ion is an ion that remains unchanged
Why is carbon often used to extract metals from their oxides?
Carbon is cheap and abundant so it is often used to extract metals from their oxides
What happens at the cathode?
Reduction occurs at the cathode
What happens at the anode?
Oxidation occurs at the anode
Is energy released by making bonds smaller or bigger in an endothermic reaction?
In an endothermic reaction, the energy released by making bonds is smaller than the energy required to break bonds
What are the factors that affect the rate of reaction?
The factors that affect the rate of reaction include number of collisions, use of a catalyst, temperature, surface area (solid), pressure of reactants (gas)
Why do catalysts often come as powders?
Catalysts often come as powders because they have a larger surface area
What is the rule for energy during a reversible reaction?
Energy change of forward reaction is opposite and equal to the backward reaction
What happens to the equilibrium when pressure increases?
Equilibrium shifts to favour the side with the fewer molecules of gas
Where does the equilbrium shift to favour in an endo/exo reversible reaction when temperature increases?
Equilibrium shifts to favour the endothermic reaction when temperature increases
Where does the equilibrium shift to favour in an endo/exo reversible reaction when temperature decreases?
Equilibrium shifts to favour the exothermic reaction when temperature decreases
How can we electrolyse lithium?
Lithium will only form at cathode if a molten lithium compound is electrolysed. If it is an aqueous solution, hydrogen forms at electrode because lithium is more reactive
Why does carbon electrodes have to be continuously replaced?
Carbon electrodes have to be continuously replaced because oxygen reacts with the electrode at high temperatures, so the electrode gets worn away and produces carbon dioxide
What happens to copper ions in electrolysis?
In electrolysis, copper is reduced and so the concentration of copper ions decrease - which means the blue colour fades away
