Chemistry C3 OCRgateway

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What is an exothermic reaction?
A reaction that gives energy out shown by rise in temperature e.g. burning fuels
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What is an endothermic reaction?
A reaction that takes in energy show by a decrease in temperature e.g.thermal decomposition
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What type of reaction is bond making?
Exothermic
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How do you work out energy transferred?
Energy transferred= mass of water x shc of water x temperature change
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How do you work out the energy given out?
Energy released / mass of fuel burned
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How can you measure how fast gas is produced?
Measure the change in mass using a balance or measure the volume of gas given off using a gas syringe
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How does increasing the temperature increase the rate of reaction?
Particles will have more energy so are moving faster resulting in more collisions per second
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How does increasing the concentration/pressure increase the rate of reaction?
There will be more particles to react with in the same amount of space so collisions are more likely
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How does increasing the surface area increase the rate of reaction?
There is more surfaces for particles to react with so there will be more collisions
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How does using a catalyst increase the rate of reaction?
Gives the reacting particles a surface to stick to where other particles can bump into them saving energy so number of successful collisions are increased
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How do you work out the average,approximate and initial rate of reaction?
Average - volume(cm3) / time(s). Approximate - 1 / time(s). Initial - y/x.
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How do you work out the atom economy?
Atom economy=total Mr of desired products/total Mr of all products x 100
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What does the atom economy show?
What percentage of the reactants were turned into useful products
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What are the benefits of a high atom economy?
Not as many waste materials to dispose of, more sustainable and more profitable as the raw materials are being used well
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How do you work out the percentage yield?
Percentage yield=actual yield / predicted yield x 100
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What does the percentage yield show?
How successful the reaction was
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Why are percentage yields always less than 100% ?
Due to evaporation, not all reacts react to make product, filtration and the transfer of liquids
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What is batch production?
Production that only operates at certain times e.g. pharmaceutical drugs
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What are the advantages and disadvantages of batch production?
Its flexible and start up costs are low however it's labour intensive and difficult to keep the same quality form batch to batch
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What is continuous production?
Production that runs all the time e.g. the Haber process to make ammonia
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What are the advantages and disadvantages of continuous production?
It never stops, runs automatically, consistent quality however start up costs are very high
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Why does it cost a lot to produce pharmaceutical drugs?
Research and development , trialling and manufacture
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How do you extract raw materials from plants?
Crush the plant then boil in a suitable solvent to dissolve it. Next use chromatography to separate the chemicals and extract the one you need
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How can you test for purity?
Pure substances won't be separated by chromatography. Impure substances will have a lower melting point and higher boiling point
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What is the definition of an allotrope?
Different structural forms of the same element in the same physical state
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What are the properties of diamond?
Lustrous, colourless, very hard, high melting point and doesn't conduct electricity
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What are the properties of graphite?
Black, opaque, shiny, lubricating, high melting point and conduct electricity
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Why are diamond and graphite giant molecular structures?
As carbon can form covalent bonds with itself therefore forming giant molecular structures like diamond and graphite. They have high melting points and don't dissolve in water.
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What are fullerenes?
Molecules of carbon shaped like hollow balls or closed tubes
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What can fullerenes be used for?
To cage other molecules e.g to cage a drug for slow release. Or they could form nanotubes which have a large surface area so could make great catalysts
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Other cards in this set

Card 2

Front

What is an endothermic reaction?

Back

A reaction that takes in energy show by a decrease in temperature e.g.thermal decomposition

Card 3

Front

What type of reaction is bond making?

Back

Preview of the front of card 3

Card 4

Front

How do you work out energy transferred?

Back

Preview of the front of card 4

Card 5

Front

How do you work out the energy given out?

Back

Preview of the front of card 5
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