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43 Cards in this Set
- Front
- Back
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What does the rate of reaction measure? |
How much product is formed in a fixed period of time |
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Why do reactions slow over time? |
The reactants begin to run out |
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How can the rate of reaction be calculated on a graph? |
Working out the gradient using construction lines: X/Y |
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What is the limiting reactant? |
The reactant not in excess that gets used up by the end of the reaction |
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The amount of product formed is ______ to the amount of the limiting reactant used. |
directly proportional |
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How can we increase the rate of reaction? |
-Increase concentration of reactants -Increase temperature and thus kinetic energy -Increase in pressure forces particles closer together |
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What does the rate of reaction depend on? |
Collision frequency |
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What is needed for a successful collision to occur? |
Sufficient kinetic energy |
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It's called leverage, Sam |
Learn it, live it, love it |
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What is the purpose of combustible powders? |
Cause explosions |
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What happens when combustible powders react with oxygen? |
They form large amounts of carbon dioxide and water vapour. |
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Name some combustible powders. |
Flour, custard powder and sulfur. |
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Why do powdered reactants work better than blocked ones? |
Larger surface area so more particles are exposed for more collision |
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Why will one catalyst work on one reaction but not another? |
Because catalysts are specific to different reactions |
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What is the relative atomic mass? |
The mass of all atoms in an element. The largest number on the periodic table; the one on top. |
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What is the conservation of mass? |
The mass of reactants is equal to the mass of products. This is because atoms cannot be created or destroyed, only rearranged. |
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What is the equation for percentage yield? |
actual yield/predicted yield (x100) |
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Why do industrial processes need to have a high percentage yield? |
-Waste less reactants because they're costly -Ensure enough reactants used as too little reduces the amount of product -Reduce production of unwanted products which can be expensive to dispose of -More sustainable, conserving raw materials |
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Bond breaking is an ______ reaction Bond making is an _______ reaction |
endothermic exothermic |
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Equation for energy per gram? |
energy released (J) / mass of fuel burnt (g) |
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What is continuous processing? |
Makes large amounts of the product 24/7 |
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Where does continuous processing take place? |
Large chemical plants with good transport links. |
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Why does continuous processing have low costs? |
It's a largely automated process which means less workers needing to be paid- less must be charged overall. |
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Advantages VS disadvantages of continuous processing? |
-Large amounts 24/7 -Less energy to maintain -Lower costs DIS -Process is inefficient if not in constant use -Initial set up is very expensive |
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What do we make with continuous processing? |
Sulfuric acid, ammonia, etc |
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Adv VS disadv of batch processing? |
-Allows batches to be stored until needed -Easy to make a new batch when needed -Easy to change production DIS -Labour intensive supervision is expensive -If product line is changed, cleaning time is needed -Inefficient because it's not ALWAYS in use |
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How does one extract a chemical from a plant? |
-Crush to disrupt cell walls -Boil in a solvent to dissolve compounds -Chromatography to separate the identify compounds -Isolate and purify (and test) potentially useful compounds |
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What kind of compound has a set melting/ boiling point? |
A pure one, son. |
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What do we use thin layer chromatography for? |
Testing the purity of a compound by comparing the speed of movement against a known pure sample. |
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Why is it difficult and expensive to get a licence for a new medicine/drug? |
-Thousands of compounds are tested before a useful one is found and must be tested on living tissue for safety reasons -Long term trails on humans identify side effects and recommended doses -Patents often expire before costs are recouped |
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What are allotropes? |
Different structures of the same element. E.G diamond, graphite and fullerenes.
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What are fullerenes? |
Carbon structures that form spheres or tubes |
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What can we use fullerenes for? |
-To carry and deliver drug molecules around the body -Trap dangerous substances in the body and remove them |
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How many carbon atoms does BUCKMINSTERFULLERENE contain and in what order? |
Spherical, 60 atoms- written as C60 |
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How long is a nanometre? |
10-9 (ten to the minus nine) |
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What kind of bonds are there between carbon atoms? |
Covalent bonds |
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Describe the carbon structure of graphite |
Every carbon is covalently bonded to three others in flat hexagonal layers. The layers only have weak attraction. |
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What properties of diamonds make them good tools? |
High melting and boiling point Hardest natural substance known to man |
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What makes graphite good for pencils? |
The layers slide over eachother and detach etc |
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What makes graphite a good high temperature lubricant? he he he he |
The layers that move over eachother make it slippery but it's also got a very high melting/boiling point. |
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Describe the carbon structure of diamond |
Strong covalent bonds in all directions |
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What is diamond's melting point? |
3350 degrees celcius |
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Why are nanotubes used in catalyst systems? |
Atoms of the catalyst can be attached to the nanotube's large surface area. |
