Karteikarten
Chemistry C8&9
Karten in diesem Stapel (70)
- 1Define rate of reactionThe rate of reaction is how fast the reactants are changed into products
- 2What are the units for different rates of reactionCm3/s
g/s
Mol/s - 3How do u calculate the mean rate of reaction ?Rate of reaction=amount of reactant used or amount of product formed divided by the time
- 4What can u monitor during a reaction-the visual change
-observe a mark and see how long it takes to disappear
-see how long it takes to gain or loose colour
-if people don't agree when a mark disappears plot it on a rate of reaction graph - 5How do u calculate the rate of reaction between two points at time ?Plot a graph.
Mean rate of reaction=change in y divided by change in x
E.g (19cm-15cm)divided by 20s - 6Explain why there is more than one unit for rate of reactionGas-cm3
Solid-grams
Time-seconds
Amount of product-miles - 7Question TextAnswer Text
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- 11Define a reversible reactionA chemical reaction where the reactants form products that in turn react together to give the reactants back
- 12Write a word equation for a familiar reversible reactionHydrated copper(II)->anhyrous copper(II)+water
This is a test for water
Meant to be double arrow - 13Define a catalystA substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change
- 14How does adding a catalyst affect the rate of reactionDifferent catalyst are needed for different reactions but they all work by decreasing the activation energy for the reaction to occur. They do this by providing an alternative reaction pathway with a lower activation energy
- 15Define a hydrocarbonA compound of hydrogen and carbon such as any of those which are the chief components of petroleum or natural gas
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- 20What does the rate of the chemical reaction depend on ? Collision theoryThe collision frequency of reacting particles-the more collisions there are the faster the reaction is
The energy transferred during the collision-particles have to collide with enough energy for the collision to be successful - 21Question TextAnswer Text
- 22Define complete combustionWhen there's plenty of oxygen all the fuels burn-this is called complete combustion
- 23What's incomplete combustionIf there's not enough oxygen some of the fuel doesn't burn-this is called incomplete combustion
- 24Describe what the activation energy of a reaction is ?The minimum energy which must be available to a chemical system with potential reactants to result in a chemical reaction
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- 27What's the dynamic equilibriumAs the reactants react, there concentrations fall so the forward reaction will slow down. But as more products are made and there concentrations rise, the backward reaction will speed up. After awhile the forward reaction will be going at exactly the same rate as the backward one-the system is as equilibrium.At equilibrium both reactants are still happening but there no overall effect. This means the concentration of reactants and products have reached a balance and won't change. It only reaches this in a closed system.
- 28What is a closed system ?It means that none of the reactant or products can escape and nothing else can get in
- 29Describe how changing concentration affects the rate of reaction ?The reactant particles become more crowded-there is a greater chance of the particles colliding,so the rate of reaction increases
- 30Describe how changing pressure affects the rate of gas phase reactionsChanging the pressure of a gas changes the rate of a reaction. Increasing the pressure of the reactant increases the rate of reaction.Changing pressure with solids or liquids has no effect
- 31State le chateliers principleIt's the idea that if you change the conditions of a reversible reaction at equilibrium the system will try to counteract that change.It can be used to predict the effect of any changes you make to a reaction system such as change to temperature,pressure or concentration
- 32Write a word equation for complete combustionHydrocarbon+oxygen ->carbon dioxide +water (energy)
- 33Name the different fractions of crude oilFrom bottom to top with number of hydrocarbons -
Heavy fuel oil-40
Diesel oil-20
Kerosene-15
Petrol-8
Liquefied petroleum gas-3 - 34What is each fraction used for ?Heavy fuel oil-Heating oil,fuel oil or lubricating oil
Diesel oil-lorrys
Kerosene-planes
Petrol-cars
LGP-commercial heating - 35Explain how the chain length affects the properties of crude oilShort chain hydrocarbons are flannel so they make good fuels and are in high demand however long chain hydrocarbons form thick gloopy liquids like tar which aren't that useful. As temp decreases chain length decreases
- 36How can you make predictions about properties of crude oil there chain lengthBecause If they have a short chain length e.g 3 hydrocarbons it means that it will be a gas or a thin liquid where as if it has a long chain length e.g. 40 hydrocarbons it would be more of a thick gloopy liquid
- 37Write a word equation for incomplete combustion of hydrocarbonAlkene+oxygen->carbon+carbon monoxide+carbon dioxide +water (energy)
- 38Describe the how the trend in colour,viscosity,flammability and boiling point change as the length of the hydrocarbon chain changesLong chain length-dark in colour, high boiling point, high viscosity,solid(dense)
Short chain length-lighter in colour, lower boiling point,lower viscosity - 39Explain in detail how fractional distillation is used to separate crude oil into fractionsCrude oil is a fossil fuel and is formed from the remains of plants and animals mainly plankton that died millions of years ago and buried in mud. Over all these years with high temp and pressure it turned into crude oil and can be drilled up from rocks.Its made up of lots of different hydrocarbons which most are alkenes. The oil is heated until most of it is turned into gas and then it enters the fractionating column and in there there's a temperature gradient. The long hydrocarbons have high boiling points so they condense back into liquids and drain out of the column early on. The shorter hydrocarbons have lower boiling points and they condense and drain out much later on near the top of the column where it's cooler.
- 40how do you generate and balance a word equation for cracking.Enter text here...
- 41explain using a familiar reaction, how a reaction can be reversibleEnter text here...
- 42what is an enzyme and how does it work?a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.Enzymes are highly selective catalysts, meaning that each enzyme only speeds up a specific reaction. The molecules that an enzyme works with are called substrates. The substrates bind to a region on the enzyme called the active site. There are two theories explaining the enzyme-substrate interaction
- 43what are the differences between complete and incomplete combustion.Incomplete combustion occurs when the supply of air or oxygen is poor. Water is still produced, but carbon monoxide and carbon are produced instead of carbon dioxide. The carbon is released as soot. Carbon monoxide is a poisonous gas, which is one reason why complete combustion is preferred to incomplete combustion.
- 44what is an alkaneany of the series of saturated hydrocarbons including methane, ethane, propane, and higher members.
- 45what is an alkeneany of the series of unsaturated hydrocarbons containing a double bond, including ethylene and propene.
- 46Describe how the change in surface area affects the rate of reactionThe larger the surface area the quicker the rate of reaction
- 47Use collision theory to explain how changing temperature alters the rate of reactionWhen the temperature is increased the particles all move faster so this means they're going to collide more frequently.Also the faster they move the more energy they have so more of the collisions will have enough energy to make the reaction happen
- 48What is the general molecular formula for a straight chain alkane
- 49explain why fractional distillation is used to separate crude oil into fractionsCrude oil can be used to make loads of useful things such as fuels, but you cant just put crude oil into a car. First the different hydrocarbons which have completely different properties and are all used for different things have to be separated and that is why fractional distillation is used.
- 50Explain how increasing the surface area increases the rate of reaction using collision theoryIf one of the reactants is a solid, then breaking it up into smaller pieces will increase its surface area to volume ratio. This means that for the same volume of solid the particles around it will have more area to work on, so there will be collisions more frequently.
- 51draw a graph that can be used to show rate of reactionEnter text here...
- 52why do many collisions not lead to a chemical reactionBecause some have to little energy so they do not produce a reaction
- 53describe how the properties of a fraction of crude oil make it appropriate for its use's? (kerosene) plane fuelcompared to heavier fuels like diesel, it is not as volatile as lighter fuels like gasoline while still having a good specific energy value. Diesel would tend to gel at temperatures at a jet's cruising altitude. It burns longer, thus lasting a bit longer so it is cheaper than petrol diesal over the same distance.
- 54describe a method which monitors rate of reactionEnter text here...
- 55justify why a chemical would be an alkane?Solid alkanes are normally soft, with low melting points. These characteristics are due to strong repulsive forces generated between electrons on neighboring atoms, which are in close proximity in crystalline solids. The strong repulsive forces counterbalance the weak van der Waals forces of attraction.
- 56describe a method used in schools of separating crude oilEnter text here...
- 57symbol equation for incomplete combustionmethane + oxygen arrow carbon monoxide + water.
2CH4(g) + 3O2(g) -> 2CO(g) + 4H2O(l) - 58symbol equation for complete combustionmethane + oxygen arrow carbon dioxide + water + energy
CH4(g) + 2O2(g) -> CO2(g) + 2H2O(l) - 59justify given use of a fuel over anotherEnter text here...
- 60explain how the production of carbon monoxide in incomplete combustion can be lethalThe hydrogen is still oxidized to water but instead of carbon dioxide we get carbon monoxide. This is a toxic gas that sticks to the hemoglobin in our red blood cells which lower's the capacity of blood to carry oxygen to our cells.
- 61describe the process of cracking using conditionsCracking allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules. Fractions containing large hydrocarbon molecules are vaporised and passed over a hot catalyst. This breaks chemical bonds in the molecules, and forms smaller hydrocarbon molecules.
Cracking is an example of a thermal decomposition reaction. - 62explain similarities and differences between alkanes and alkenesdifference-alkane is a saturated and is relatively unreactive hydrocarbon whereas alkene is an unsaturated hydrocarbon and is reactive
similarities-both hydrocarbons - 63Name an industrial catalystcatalytic converter-It performs three simultaneous tasks, namely, reduction of nitrogen oxides to nitrogen and oxygen, oxidation of carbon monoxide to carbon dioxide, and oxidation of unburnt hydrocarbons to carbon dioxide and water.
- 64surface area to volume ratioas things get smaller their surface area to volume ratio gets bigger
- 65how do you change gas pressurealter the temperature.
- 66explain using collision theory how changing the concentration and pressure alters the rate of reactionEnter text here...
- 67why would a small chain of hydrocarbons be betterless viscous
lower boiling point ( more volatile)
more flammable
used as a bottled gas
stored under pressure as liquids in bottles - 68what is the reaction between bromine water and alkaneEnter text here...
- 69reaction between bromine water and alkaneEnter text here...
- 70Talk about catalyst using collision theoryThey do not increase frequency of collision between reactant particles nor do they make collisions any more energetic
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- Beschreibung
- GCSE Chemistry Karteikarten am Chemistry C8&9, erstellt von ella stokes am 17/12/2016.
- Erstellt von
- ella stokes
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