GCSE Chemistry 2020-2022 OCR Gateway
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GCSE Chemistry 2020-2022 OCR Gateway - Leaderboard
GCSE Chemistry 2020-2022 OCR Gateway - Details
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How close are the atoms in a solid state? | They are touching each other with their movenment being restricted to vibration. |
How close are the atoms in a liquid state? | They are close and just slid on top of each other but can move more freely than the solid. |
How close are the atoms in a gas state? | They are far away from one and each other can move anywhere they want. |
What is a chemical change? | Its when the particles rearrange to become something new. This also can change the formula. eg Water breaking down to Hydrogen and Oxygen. |
What is a physical change? | This is when the substance changes state with no affect to its formula. eg Melting Bromine. |
How [roughly] big is an atom? | 10 [x10 to the power of -10] |
What is an element? | An element is made of 1 type of atom and is also pure. |
What does pure mean? | Pure means made of 1 element/compound and not mixed together. |
What is a solute? | A solute is when a substance has been dissolved in a solution |
What is a solvent? | A solvent is the substance that dissolves the solute. |
What is a solution? | A solution is when a solvent and solution exist in one. eg salt water. Salt is a the solute while water is the solvent. |
How are electrons arrenged? | The first shell or orbit would have 2 maximum. then the next shell would have 8 and the third would have 8. |
What does Chromatography mean? | Chromatography is the process that when a gas or a liquid dissolves a mixture to separate it. |
What does residue mean? | Residue is whatever is leftover after the separation. |
What does soluble and insoluble mean? | Soluble mean that the substance can dissolve in the solvent where as insoluble means it cant. |
What is the filtration process? | This is when the solid gets separated from the liquids and gases from a filter medium that doesn't let the solid through. The filtrate is the product |
What is the Rf value? | The Rf value is the distance from your baseline to the middle of the colour spot divided by the distance from your baseline to the solvent front. |
What is the 'mobile phase' [in the ink experiment] | The mobile phase is usually the solvent. eg Water. |
What is the 'stationary phase' [in the ink experiment | The stationary phase is usually a solid that holds the solvent. eg Beaker. |
Appearance of the Metals and Non-metals? | Metals are shiny, while non-metals are dull |
Melting point for Metals and Non-metals | Metals have quite a high melting point, while Non-metals have a low melting point |
State of Metals and Non-metals at Room temperature | Metals are useally solid, while Non-metals are in a mix with solid and gas |
Malleable of Metals and Non-metals | Metals can bend without shattering while Non-metals can be shattered |
Ductile of Metals and Non-metals | Metals can be pulled to wires while Non-Metals cant be pulled. It snaps |
Thermal and Electrical conductivity of Metals and Non-metals | Metals are good conductors for both, while Non-metals are poor. They are a insualtor. |
Any exceptions? | Mercury is a liquid at room temperature |
What does IUPAC stand for? | It stands for International Union of Pure and Applied Chemistry |
What are Metals and Non-metals chemical properites? | Metals lose electrons to become positive ions. Non-metals gain electrons to form negative ions |
Do Metals react with eachother? | No. They can mix to become Alloys which is different |
What happens to Metals and Non-metals oxides when they dissovle in water? | Metals makes an Alkaline solution, Non-metals make a Acidic solution. |
How to test on a element to see if its a metal or non-metal. | You oxides the element and then disovle it in water. If its an Alkaline solution, its a Metal. If its an Acdic solutoin, its a Non-Metal. |
What is an Ion | Ions is when a atom gains/loses a electron |
What is an Ion? Give examples. | This is simply a charged particle. Cl- [Chloride] or NO3 [Ammonium Ions] |
Which groups are Metals and Non-metals | Group 1-2 are metals, Group 6-7 are non-metals |
Why do Atoms become Ions. | This is to full the Electron Outer Shell. This is a stable place from Atoms. They achieve this by Loosing an Electron, or gaining. |
What makes Group 1-2, 6-7 special | Group 1-2 lose electrons to make a positive ion. Group 6-7 gain electrons to make negative ions. They both dont have complete electron shells. |
What happens when Metals and Non-Metals become Ions? | Metals become Ions by Loosing an Electron, making a Positive Ion Non-Metals become Ions by Gaining an Electron, making a Negative Ion |
What happenes when they react? | The Metal loses it electron which goes to the Non metal. Now the metal is a positive ion [+1] and the Non-Metal is a negative ion [-1] They are now strongly attached and both have complete electron shells. They have made an Ionic bond via Electrostatic forces |
What are the 4 Groups in the Periodic Table to most likely form Ions | Group 1-2 and Group 6-7. |
What is an Ionic Latice structure | This is simply the protons and electron being next to each other by electronstatic forces from around them. Crystals can form from this, as they have many ions |
Which Groups are the Metals, and the Non metals. What charge do they form? | Group 1 is Metals, They make a +1 Charge. [They lose 1 electron] Group 2 is Metals, They make a +2 Charge [They lose 2 electrons] Group 6 is Non-Metals. They make a -2 Charge [They gain 2 Electrons] Group 7 is Non-Metals. They make a -1 Charge [They gain 1 electron.] |
Melting and Boiling point of the Ionic compounds? | They are high as because of the reqired energy needed to break that electrostatic force [attraction] |
What do the Elements in G1-2 and G6-7 have in common? | They all have a Full Outer Shell once reacted. This is usually 8 |
Can they conduct electrcity? | Not in a solid state, as they are fixed in place. However, when it melts, it can conduct electricity as the ions can move. It can dissolve too, and still have that electric charge. |
What is the Reactivity Series for G1-2 and G6-7 | G1-2 has it getting easier to Remove the Outer Electrons [Gets More Reactive as you go down the Group] G6-7 has it getting the Electron Harder for the Nucleus [Gets Less Reactive as you go down the Group] |
Explain the Reactivity Series for G1-2 and G6-7 | G1-2 gets more Reactive because the Electron is further away from the Nucleus, the Atom is bigger and the Attraction of the Positive Nucleus and the Negative Electron is Weaker G6-7 gets Less reactive because the Positive Nucleus can spend More Energy to gain a Electron, because its Closer. As you go down, the Attraction gets weaker. |
What happens when a Metal and a Non Metal reacts? | So the Metal can Lose the Outer Electron/s making a Positive Ion, and that Lost Electron is given to the Non-Metal, which turns into a Negative Ion. These Ions are Oppositely Charged meaning that they can be Attracted together by strong Electrostatic Forces. This creates an Ionic Bond |
What happens when 1. Sodium reacts with Chlorine 2. Magnesium with Chlorine | 1. Potassium is a G1 Element meaning its going to lose 1 electron [+1 Charge] Chlorine is a G7 Element meaning it wants 1 Electron [-1] Charges are balanced out meaning they can make NaCl [Sodium Chloride] 2. Magnesium is a G2 Element meaning its going to lose 2 Electron [+2] Chlorine is a G7 Element meaning it wants 1 Electron. The charges here are Not Balanced, but we make it by adding another Chlorine, making it want 2 Electron [-2] So now we can have Magnesium Chloride [MgCl2] [small 2] |
So what does it mean when an Ionic Compound has a Giant Ionic Lattice Structure? | This is simply the Ions making a Close Packed arrangement, that has Strong Electrostatics Forces keeping it in Place, in All Directions. This has no Gaps. |
What are some of the Properties that an Ionic Compound hosts? | -They have a High Melting Point, along with a High Boiling Point because of the Energy needed to break the Electrostatic Force of Attraction -They can't conduct Electricity, in a Solid State, as the Ions can not Move [From the Electrostatic Forces in the Lattice Structure] but when its in a Liquid State, the Ions Can Move, which can carry Electricity -They can also easily dissolve in Water, which splits up the Ions, and can also carry an Electric Charge |
Why are liquids sour | They contain a weak acid [carbonic acid] |
What can strong acid do? | Potentially erode metals and destroy skin [hyrdochloric acid] |
What is the pH of acids, neutral and alkilines | 1-6 for acids, 7 for neutral and 8-14 for alkaline |
How can you tell if its acidic or alkaline? | You can use a universal indicator. A colour will appear in your solution and from that you can use the pH scale. Red is acidic, Green is Neutral and Purple/Blue is Alkaline. You can also use Litmus paper. You simply dip the paper in and the paper will change colour. Use the pH scale from their pH meter is another way and its electronic. Do the same with Litmus paper and will tell you the accurate pH. This one is used for more dangerous ones [1-2 or 13-14] |
What happens to acids and alkalis in water? | Acids make acidic solution which contains hydrogen ions [H+] An example would be Hydrochloric acid [HCl--H+,Cl] Alkalis make alkaline solutions which contains Hydroxide ions [OH-] An example would be sodium hydroxide [NaOH--Na+OH-] |
What is Neutralisation? | This is when a acid reacts with a alkaline or a base to make a salt and water. Example would be with an oxide= Copper oxide + Sulfuric acid = Copper Sulphate + Water. If a acid and alkaline reacts, the salt would be combination for the both. [Sodium + Hydrochloric = Sodium Chloride + Water] |
What happens if a acid neutralises a base? | The product from those two reactants will have a pH of 7. The concentration of Hyrdogen ions is the same as Hydroxide ions. |
What are Titration? | This is used to work out how much acid is used to neutralise the base with a unknown concentration. Opposite is true. Titration curves show where neutralisation happens in the Titration. The vertical point shows where the solution is neutral [pH of 7] |
What are Exothermic and Endothermic reactions | Exothermic is a reaction that gives out energy. Endothermic is a reaction that takes in energy |
Examples of Exothermic and Endothermic reactions | Exothermic: Burning a material with oxygen releases heat [energy] This makes combustion a exothermic reaction. Endothermic: Baking a cake. Sodium bicarbonate gets broken down into sodium carbonate. water and Carbon dioxide which rises the cake. |
How can reactions be Exothermic or Endothermic | Bonds breaking or creating. Breaking bonds in compounds requires energy. Creating bonds releases energy. If more bonds are broke then created, its endothermic. If more bonds are created then broke, its exothermic |
How to test if the reaction was Exothermic or Endothermic | -The surrounding temperature can help us out. -If its has increased, that means its exothermic. -If its decreased in temperature, its endothermic. -Another way is putting water under your beaker. I -f it freezes, its endothermic [the reaction has to go below 0 degrees.] |
What is the graph called to represent the reaction? | Its called a Energy profile. |
What does it look like in Exothermic or Endothermic [energy profile] | -Exothermic would have reactants have more energy then the products. This is because energy is released. Its a n shape from reactants to products as it needs to reach Activation energy. This is the minimum amount of energy for the reaction to begin really. -Endothermic is opposite. Reactants have less energy then the products as it takes in energy. its a n shape with again having activation energy. |
Why do you need a certain amount of energy for the reaction to happen? | -Particles collide with each other for reactions to happen. -Energy allows them to move faster and faster. |
How to find out Bond energy? | Exams usually provide us with two things. The structure and the energy value. With that you can have compound and the energy needed to create/break them. An example would be Hydrogen + Chlorine. H--H + Cl--Cl = H-Cl. H--H=436 kj/mol, Cl--Cl=242 kj/mol H--Cl=431kj/mol On the left hand side, we are breaking the bonds. The answer would be positive as because it requires energy. [678kJ] The right hand side is making bonds so it would be negative as it releases energy. [-862kJ] [678-862=-184kJ] This reaction is Exothermic, as energy is being released [its negative] |
What exactly is Activation Energy? Where is it shown on a Reaction Graph? | -This is simply the amount of energy needed to Break Bonds -On the Reaction Profile, it is the Energy Difference between the Reactants, and the Highest Point on the Curve -So if the Energy input isn't enough to hit the Activation Energy, nothing will happen |
What happens in terms of Energy and Breaking/Making Bonds? | -When bonds need to be Broken, Energy has to be given in. This is an Endothermic Process [Energy is Used] -When bonds need to be made, Energy is Released from it. This is an Exothermic Process [Energy is Given] |
So in terms of Bond Energy, what happens in Exothermic and Endothermic reactions Always? | -If its an Exothermic Reaction, the Energy Released by making Bonds will be Greater than the Energy needed to Break them -If its an Endothermic Reaction, the Energy Used will be Greater than the Energy Released from Making the Bonds |
Formula of Overall Energy Change? -What happens if the Result is Positive Negative | -Overall Energy Change = Energy Required to Break Bonds - Energy Released by forming Bonds -If Positive, its an Endothermic Reaction -If Negative, its an Exothermic Reaction |
What happens in a Chemical reaction? | The atoms rearrange themselves. |
How is an equation set? | The right hand side is the Reactants [which react] and the left hand side is the Products [the results] |
Example of an equation | Aerobic Respiration reactants are Glucose and Oxygen, Products are Carbon Dioxide and Water |
What is a catalyst? | This is something that speeds up the reaction without changing chemically. eg Enzymes |
What is the conservation of mass? | This is the rule that no atoms are created/destroyed in a reaction. The mass of the products will be the same as the reactants. |
What is a Displacement reaction? | This is when a metal and a compound with a different metal react. The more reactive metal will move/take over/displace the less reactive metal from the compound. |
What is Group 1 more known as? | The Alkali Metals |
What is Group 7 more known as? | The Acidic Metals [Halogens] |
What does Group 1 and 7 contain? | Group 1: Lithium, Sodium, Potassium, Rubidium, Caesium, Francium Group 7: Fluorine, Chlorine, Bromine, Iodine, Astatine |
What is Group 1 known for? | Metals + Have one outer electron. |
How reactive can Group 1 be? | They can be very reactive. They can sizzile or can blow up. |
Why can it get more reactive [Group 1] | This is because the more ready the metal losses it electron, the more reactive it can get. The electron is futher away from the nucleus so its not as attached which makes it quite energy suffiencent to break away. |
What happens when it reacts with a dilute acid [Group 1] | A salt will be made + Hydrogen or Water. |
What is special about Group 7? | Its Non-metals + they have 1 less electron. They do exist in duos to from Covlent bonds however [to give themselves a stable electron field] |
What happens when you go down the list in the Group 7 category? | They get less reactive as its more easier it is to gain that electron. You dont need as much power |
What happens when they react with a Group 1 metal? | They make a salt called metal halides. |
What does pure mean in everyday life? | It often refers to Clean or natural |
What does pure mean in Chemistry mean? | It means that the substance is made up of a single Element or a Compound |
What happens if you have more then one compound present. Or different elements not in a compound in a solution? | It will not be pure. It will be instead a Mixture |
Is fresh air pure? | No. We think its just Oxygen, but it also contains Carbon Dioxide, Nitrogen, Water Vapor, Argon and other various gases |
What does each Pure substance have that can be tested? | It has a specific melting point and boiling point. An example would be Pure Ice. It melts at 0 degrees and boils at 100 degrees |
So how can you test for Impure substances? | -You simply find its designated melting point and boiling point and compare it with your substance. -If the melting point is too low, its impure. If the boiling point is to high, its impure. -If its the same, Its Pure |
How else can you tell if its Impure. | -You can heat the solid/liquid up. -If the substance is impure, their will be different components with different melting/boiling temperatures. -Part of the mixture will boil/melt while the other part will stay in its original state for longer. |
What is Simple Distillation used for? | This is used to Separate out Solutions |
How does this work? Use an example with Sea Water. | 1. Pour your solution into a distillation flask and heat it up 2. The component that has the lowest boiling point will evaporate. This case will be Water 3. The Water vapor will go through the condenser and will condense. [Make sure cold water is ran through to ensure it is cold] 4. The Pure Water will be in beaker while the salt will be left there, in the Distillation flask |
What problem is encountered with Simple Distillation? | One of the problems is that this can only work with mixtures that have very different boiling points. |
What is Fractional Distillation used for? | This is used to separate a mixture of liquids with similar boiling points |
Explain Fractional Distillation. Use Crude Oil as an example. | 1. Pour your mixture into a Flask. Attach said flask then to a Fractionating column that is filled with Glass Rods. 2. Heat up the mixture slowly. The different liquids again have different boiling points meaning they will evaporate at different temperatures 3. The liquid with the Lowest Boiling point will evaporate first. When the thermometer has reached the boiling point for that liquid, it will allow it to reach the Top of the Fractionating column. Other liquids may also evaporate [as there similar] but fail to reach the top, as its colder there meaning they will condense and go back down. 4. The Chosen liquid will then flow through the Condenser and fill up a Flask or a Measuring Cylinder. You then repeat to get the next one. |
What do you do if the liquid is Flammable? | If its flammable, do not use a Bunsen burner but instead use a Water Bath, or a Electronic Heater |
What is Filtration used for? | This is used to separate an Insoluble Solid from a Liquid Or in other words If the product of a reaction is an insoluble solid, Filtration will separate it from a Liquid Reaction Mixture |