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198 Cards in this Set
- Front
- Back
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What is an Atomic number |
The number of protons in the nucleus |
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What is crystallisation |
A separation technique used to produce solid crystals from a solution by evaporating the solvent |
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What is displacement |
A chemical reaction in which a more reactive element displaces a less reactive element from its compound |
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What is filtration |
A separation technique used to separate solids from liquids |
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What is fractional distillation |
Separating a mixture of substances according to their different boiling points |
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What group in the periodic table are the halogens |
Group 7 |
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What is an ion |
An atom or molecule with an Electric charge due to the loss or gain of electrons |
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What is an isotope |
Atoms of the same element with the same number of protons but a different number of neutrons |
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What group in the periodic table are the Nobel gasses |
Group 8 |
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What does the plum pudding model suggest |
The atom is a ball of positive charge with negative electrons scattered through it |
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What is simple distillation |
Where two liquids with different boiling points can be separated |
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What did Neil Bohr suggest |
Electrons orbit the nucleus at specific distances |
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What model discovered the electron |
The plum pudding model |
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What did James Chadwick provide evidence of |
The existence of neutrons within the nucleus |
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What does the atomic number tell you |
The number of protons in an atom |
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Charge of a proton |
1 |
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Charge of a Neutron |
0 |
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Charge of An electron |
-1 |
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Who created the modern day period table |
Mendeleev |
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Do metals react to form positive ions |
Yes |
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How many electrons on the outer shells do the novel gasses have |
8 - they have a full outer shell |
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Isotopes of an element have: |
The same atomic number Different mass numbers |
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What is the mass number |
The number of protons and neutrons found in the nucleus of an atom |
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What is abundance |
If there is a lot of something |
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What do compounds contain |
Two or more different elements chemically combined in a fixed proportion |
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What are the three types of chemical bonds |
Ionic Covalent Metallic |
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What type of bonding is ionic between |
Metals and non metals |
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What type of bonding is ionic between |
Metals and non metals |
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What type of bonding is covalent between |
Non metals and non metals |
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What type of bonding is ionic between |
Metals and non metals |
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What type of bonding is covalent between |
Non metals and non metals |
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What type of bonding in metallic between |
Metal and metals |
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How does ionic bonding work |
Electrons on the outer shell of metal atom are transferred Metal atom lose electrons to become positively charged ions Non metal gains electrons to become negitavely charged ions |
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What is an ionic compound |
A giant structure of ions Held together by string electrostatic forces of attraction between oppositely charged ions |
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What is covalent bonding |
When atoms share one or more pairs of electrons |
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What do small molecules such as HCL havec |
Have strong covalent bonds within their molecules |
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What do small molecules such as HCL havec |
Have strong covalent bonds within their molecules |
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What do giant covalent structures consist of |
Many atoms covalently bonded in a lattice structure |
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What do small molecules such as HCL havec |
Have strong covalent bonds within their molecules |
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What do giant covalent structures consist of |
Many atoms covalently bonded in a lattice structure |
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True or false Polymers are large covalently bonded molecules |
True |
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What do small molecules such as HCL havec |
Have strong covalent bonds within their molecules |
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What do giant covalent structures consist of |
Many atoms covalently bonded in a lattice structure |
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True or false Polymers are large covalently bonded molecules |
True |
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What does metallic bonding consist of |
Positive ions and delocalised electrons arranged in a regular pattern |
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What do small molecules such as HCL havec |
Have strong covalent bonds within their molecules |
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What do giant covalent structures consist of |
Many atoms covalently bonded in a lattice structure |
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True or false Polymers are large covalently bonded molecules |
True |
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What does metallic bonding consist of |
Positive ions and delocalised electrons arranged in a regular pattern |
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In metallic bonding what do the delocalised electrons consist of |
Electrons lost from the atoms to form positive ions |
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What are delocalised electrons free to do |
Move through the structure |
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What makes metallic bonds strong |
The delocalised electrons which are shared through the structure |
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What makes metallic bonds strong |
The delocalised electrons which are shared through the structure |
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What are the three states of matter |
Solid Liquid Gas |
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Where does melting and freezing take place |
At the melting point |
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Where does melting and freezing take place |
At the melting point |
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Where does boiling and condensing take place |
At the boiling point |
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What does the particle theory state |
The amount of energy needed to change state from soild to liquid and from liquid to gas depends on the strength of the forces between the particles of the substance |
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What does the particle theory state |
The amount of energy needed to change state from soild to liquid and from liquid to gas depends on the strength of the forces between the particles of the substance |
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What does stronger forces between particles mean for the melting and boiling point of the substance |
That the melting and boiling point is higher |
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How are the three states of matter shown in equations And for aqueous solutions |
Solid - s Liquid - l Gas - g Aqueous solutions - aq |
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What are the properties of ionic compound |
Have giant ionic lattices Strong electrostatic forces of attraction High melting and boiling points because a lot of energy is required to break the many Strong bonds When melted they can conduct electricity |
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Properties of small molecules (Usually gases or liquids) |
Have low melting and boiling points Have weak intermolecular forces Do not conduct electricity |
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Properties of small molecules (Usually gases or liquids) |
Have low melting and boiling points Have weak intermolecular forces Do not conduct electricity |
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Properties of polymers |
Have very large molecules Atoms are linked to the other atoms by string covalent bonds Intermolecular forces are relitively strong |
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Properties of giant covalent structures |
Solids with very high melting points All atoms linked to other atoms by string covalent bonds |
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Properties of giant covalent structures |
Solids with very high melting points All atoms linked to other atoms by string covalent bonds |
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Properties of metals |
Giant structures of atoms with string metallic bonding High melting and boiling points Layers of atoms are able to slide over each other so metals can bend which makes them usefull for certain things |
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Properties of alloys |
Alloys are made up from 2 or more different types of metals Hard for the atoms to slide over each other |
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Properties of alloys |
Alloys are made up from 2 or more different types of metals Hard for the atoms to slide over each other |
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Are alloys or pure metals harder |
Alloys |
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How are metals good conductors |
Good conductors if electricity- delocalised electrons carry electrical charge through the metal Good conductors if thermal energy- energy is transferred by the delocalised electrons |
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Features of dimond |
Each carbon is joined to 4 other carbons covalently Very hard Has a high melting point Does not conduct electricity |
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Structures of graphene |
Single layer of graphite Very strong because atoms within its layers are tightly bonded |
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Structures of graphene |
Single layer of graphite Very strong because atoms within its layers are tightly bonded |
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What can carbon form |
Fullerenes with different number of carbon atoms |
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Structures of graphene |
Single layer of graphite Very strong because atoms within its layers are tightly bonded |
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What can carbon form |
Fullerenes with different number of carbon atoms |
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What can nanotubes be used for |
Reinforcing materials |
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What does the law conservation of mass |
No atoms are lost or made in a chemical reaction Instead the atoms join together in different ways to form products |
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How can the mass of one substance in a reaction be calculated |
If the masses of the other substances are know |
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What is a closed system |
A system in which no substance can renter or leave during a reaction |
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What is neutralisation |
The reaction between an acid and a base to from a salt plus water |
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What is a non-enclosed system |
A system in which gases or other substances can enter or leave during a reaction |
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What does the law of conservation state |
The total mass of the reactants in a chemical reaction is equal to the total mass of the products |
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What is oxidation |
When a substance gains oxygen |
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What is oxidation |
When a substance gains oxygen |
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What is reducation |
When a substance loses oxygen |
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What is the reactivity series of metals |
Shows the metals in order of their reactivity |
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What is a displacement reaction |
Where a more reactive metal displaces a less reactive metal from a compound |
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How are unreactive metals found in earth |
In their natural state |
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How can metals less reactive that carbon be extracted |
Reduction with carbon Carbon displaces in metal in the metal oxide |
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How are metals more reactive that carbon extracted |
By electrolysis |
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Which metals in the reactivity series will react with acid |
Those above hydrogen |
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Which metals in the reactivity series will react with acid |
Those above hydrogen |
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What is the equation for a neutralisation reaction |
Base + acid —> salt + water |
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How is a soluble salt formed |
React the excess axis with some insoluble chemicals Filter off the leftovers Crystallise the product |
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What do acids and alkalis produce is aqueous solutions |
Acids produce hydrogen ions Alkalis produce hydroxide ions |
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What are: Bases Acids Alkalis |
Bases - compounds that neutralise acids Acids- produce hydrogen ions in aqueous solutions Alkalis- soluable bases |
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What are: Bases Acids Alkalis |
Bases - compounds that neutralise acids Acids- produce hydrogen ions in aqueous solutions Alkalis- soluable bases |
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What the pH scale do |
Measure the acidity and alkalinity of a solution |
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What does a pH of 7 show |
A neutral solution |
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What is electrolysis |
The passing of an electric current through ionic substances that are molten or in solution to break them down into elements |
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What is an electrolyte |
The liquid/ solution which conducts electricity |
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What is a cathode and anode |
A cathode is a negative electrode An anode is the positive electrode |
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What is a cathode and anode |
A cathode is a negative electrode An anode is the positive electrode |
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What occurs at the cathode and anode during electrolysis |
Reduction occurs at the cathode Oxidation occurs at the anode |
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How is aluminium manufactured |
Through the electrolysis of aluminium oxide and cryolite |
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Why is cryolite used in manufacturing of aluminium |
It lowers the melting point of aluminium oxide |
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How to test for hydrogen |
Put a lit splint into a test tube and if hydrogen is present u will hear a squeaky pop |
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How to test for oxygen |
Put a glowing splint into gas If oxygen is present the splint will relight |
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How to test for chlorine |
A damp litmus will bleach white if chlorine is present |
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How to test for carbon dioxide |
If carbon dioxide goes through lime water it will turn cloudy |
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How to test for alkenes |
Use bromine water If there is an alkene it will turn from orange to colourless |
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What is the conservation of energy principle |
Energy is conserved in chemical reactions Amount of energy in the universe at the end of a chemical reaction is the same as before the reaction takes place |
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What is an exothermic reaction |
A reaction where energy is transferred to the surrounding Surrounding temperature is increased |
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What is an exothermic reaction |
A reaction where energy is transferred to the surrounding Surrounding temperature is increased |
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Examples of exothermic reactions |
Combustion Oxidation reactions |
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What is an endothermic reaction |
A reaction where energy is taken from the surroundings Surrounding temperature decreases |
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What is an endothermic reaction |
A reaction where energy is taken from the surroundings Surrounding temperature decreases |
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What is activation energy |
Minimum amount of energy that particles need to react |
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What is an endothermic reaction |
A reaction where energy is taken from the surroundings Surrounding temperature decreases |
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What is activation energy |
Minimum amount of energy that particles need to react |
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What is a reaction profile |
A graph which shows the relative energies of reactants and product |
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What is an endothermic reaction |
A reaction where energy is taken from the surroundings Surrounding temperature decreases |
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What is activation energy |
Minimum amount of energy that particles need to react |
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What is a reaction profile |
A graph which shows the relative energies of reactants and product |
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What is a cell |
Composed of two electrodes dipped in an electrolyte solution |
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What is an endothermic reaction |
A reaction where energy is taken from the surroundings Surrounding temperature decreases |
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What is activation energy |
Minimum amount of energy that particles need to react |
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What is a reaction profile |
A graph which shows the relative energies of reactants and product |
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What is a cell |
Composed of two electrodes dipped in an electrolyte solution |
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What is a battery |
Two or more cells connected in series |
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What is a rechargeable cell |
Chemical reactions are reversed when a external current is supplied |
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What is a rechargeable cell |
Chemical reactions are reversed when a external current is supplied |
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What is a non rechargeable cell |
Reactants are used up |
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Advantages of hydrogen fuel cells |
No pollutants |
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Advantages of hydrogen fuel cells |
No pollutants |
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Disadvantage of hydrogen fuel cells |
Flammable |
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The three subatomic constituents of an atom |
Proton Electron Neutron |
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Where is most of the mass of an atom concentrated |
In the nucleus |
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Describe the arrangement of protons, neutrons and electrons in an atom |
Protons and neutrons are found in the atoms nucleus Electrons are found in the energy levels around the nucleus |
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2 ways that an atoms electron arrangement can be charged |
Absorbing electromagnetic radiation Emitting electromagnetic radiation |
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2 ways that an atoms electron arrangement can be charged |
Absorbing electromagnetic radiation Emitting electromagnetic radiation |
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Explain how an atoms electron arrangement changes when it absorbs EM radiation |
Electrons move further away from the nucleus They move to a higher energy level |
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How does the ration of electrons to protons in an atom result in the atoms having no overall charge |
Number of protons is the same as the number of electrons Protons and electrons have equal and opposite charges, so charge cancels |
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What do all forms of the same element have in common |
They all have the same number of protons |
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How do atoms turn into positive ions |
They lose one or more of their outer electrons |
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How did the plum pudding model describe the atom |
A ball of positive charge with negatively Charged electrons distributed evenly throughout it |
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Before the discovery of the electron what was believed about the atom |
The atom was indivisible |
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Before the discovery of the electron what was believed about the atom |
The atom was indivisible |
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What experiment led to the plum pudding model being discarded |
Rutherford alpha scattering experiment |
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Before the discovery of the electron what was believed about the atom |
The atom was indivisible |
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What experiment led to the plum pudding model being discarded |
Rutherford alpha scattering experiment |
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What’s the name of the current model of the atom |
The Bohr nuclear model |
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State the conclusions of the Alpha scattering experiment |
Most of the mass of the atom is concentrated at the centre in the nucleus The nucleus is positively charged |
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Why do unstable nuclei give out radiation |
As they undergo decay to become more stable As They release radiation their stability increase |
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What is the name of the process in which an unstable nucleus gives out radiation to become more stable |
Radioactive decay |
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What is the name of the process in which an unstable nucleus gives out radiation to become more stable |
Radioactive decay |
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Define the activity of an unstable nucleus |
Activity is the rate of decay of a source of unstable nuclei |
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What is count rate |
The amount of radioactive decays per second for a radioactive source |
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4 types of nuclear radiation |
Alpha particles Beta particles Gamma rays Neutrons |
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What are the constituents of an alpha particle |
Two protons and two neutrons |
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What is the range of alpha particles through air |
A few cm’s |
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What will stop beta radiation from passing through a point |
Thin sheet of aluminium |
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What will stop gamma radiation from passing through a point |
Several cm of lead |
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What type of radiation is the most ionising |
Alpha |
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What type of radiation is the most ionising |
Alpha |
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What type of radiation is least ionising |
Gamma radiation |
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State any changes to mass or charge that occur due to the emission of a gamma ray |
Both mass and charge remain unchanged |
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State any changes to mass or charge that occur due to the emission of a gamma ray |
Both mass and charge remain unchanged |
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Describe the nature of radioactive decay |
Random Which nuclei decays and when it is determined is only by chance |
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Define the half life of a radioactive isotope |
The time is takes for the number of unstable nuclei in a substance to halve |
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What is radioactive contamination |
The presence of unwanted radioactive nuclei on other materials |
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What is irradiation |
The process of exposing a material to nuclear fusion |
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Give 4 sources of background radiation |
Rocks Cosmic rays from space Nuclear weapon testing Nuclear accidents |
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What is the unit used to radiation dosage |
Sieverts |
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Why might the radiation dosage that people experience be different |
Some occupations involve working with radiation |
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What factor determines how dangerous a particular radioactive isotope is |
The half life of the isotope |
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Why are isotopes a long half life particularly harmful |
They remain radioactive for much longer periods of time |
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2 uses of nuclear radiation in medicine |
Examining internal organs Controlling and destroying unwanted tissue |
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How is radiation used in sterilisation |
Gamma emitters are used to kill bacteria on equipment |
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Explain the process of radiotherapy |
Gamma emitters direct gamma rays at the cancerous cells The cancerous cells absorb the radiation and are killed |
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What is nuclear fission |
The spitting of large, unstable nuclei to form smaller more stable nuclei |
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An example of a fissionable isotope |
Uranium |
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What usually needs to happen to induce fission |
Unstable nuclei must absorb a neutron |
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What form of energy do all fission products have |
Kinetic energy |
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What takes place during a chain reaction in a nuclear reactor |
Unstable nucleus absorbs a neutron Nucleus undergoes fission and releases 2 or 3 further neutrons These induce more fission which results in a chain reaction |
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What takes place during a chain reaction in a nuclear reactor |
Unstable nucleus absorbs a neutron Nucleus undergoes fission and releases 2 or 3 further neutrons These induce more fission which results in a chain reaction |
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Consequence of an uncontrolled chain reaction |
Rate of fission becomes to high and results in production of too much energy Can lead to a nuclear explosion |
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3 main components of the core a nuclear reactor |
Fuel rods Control rods Moderator |
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Role of the moderator in a nuclear reactor |
Slow down the neutrons so they are travelling at speeds which allow them to be absorbed |
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What term is used to describe nuclei in which fission can be induced through the absorption of slow neutrons |
Fissile nuclei |
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What is nuclear fusion |
Joining it two light nuclei to produce a heavier nuclei and release energy |
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What releases more energy Nuclear fission or nuclear fusion |
Nuclear fusion |
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Explain the difficulty of generating energy through nuclear fusion |
Requires high temperatures which requires large quantities of energy |
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Explain the difficulty of generating energy through nuclear fusion |
Requires high temperatures which requires large quantities of energy |
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Why is nuclear fusion currently not viable a viable way to produce energy on earth |
With Current equipment and techniques the energy required is greater than the energy produced |
