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43 Cards in this Set

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What does the rate of reaction measure?

How much product is formed in a fixed period of time

Why do reactions slow over time?

The reactants begin to run out

How can the rate of reaction be calculated on a graph?

Working out the gradient using construction lines: X/Y

What is the limiting reactant?

The reactant not in excess that gets used up by the end of the reaction

The amount of product formed is ______ to the amount of the limiting reactant used.

directly proportional

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

What does the rate of reaction depend on?

Collision frequency

What is needed for a successful collision to occur?

Sufficient kinetic energy

It's called leverage, Sam

Learn it, live it, love it

What is the purpose of combustible powders?

Cause explosions

What happens when combustible powders react with oxygen?

They form large amounts of carbon dioxide and water vapour.

Name some combustible powders.

Flour, custard powder and sulfur.

Why do powdered reactants work better than blocked ones?

Larger surface area so more particles are exposed for more collision

Why will one catalyst work on one reaction but not another?

Because catalysts are specific to different reactions

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.

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.

What is the equation for percentage yield?

actual yield/predicted yield (x100)

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

Bond breaking is an ______ reaction


Bond making is an _______ reaction

endothermic


exothermic

Equation for energy per gram?

energy released (J) / mass of fuel burnt (g)

What is continuous processing?

Makes large amounts of the product 24/7

Where does continuous processing take place?

Large chemical plants with good transport links.

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.

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

What do we make with continuous processing?

Sulfuric acid, ammonia, etc

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

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

What kind of compound has a set melting/ boiling point?

A pure one, son.

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.

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

What are allotropes?

Different structures of the same element.


E.G diamond, graphite and fullerenes.


What are fullerenes?

Carbon structures that form spheres or tubes

What can we use fullerenes for?

-To carry and deliver drug molecules around the body


-Trap dangerous substances in the body and remove them

How many carbon atoms does BUCKMINSTERFULLERENE contain and in what order?

Spherical, 60 atoms- written as C60

How long is a nanometre?

10-9


(ten to the minus nine)

What kind of bonds are there between carbon atoms?

Covalent bonds

Describe the carbon structure of graphite

Every carbon is covalently bonded to three others in flat hexagonal layers. The layers only have weak attraction.

What properties of diamonds make them good tools?

High melting and boiling point


Hardest natural substance known to man

What makes graphite good for pencils?

The layers slide over eachother and detach etc

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.

Describe the carbon structure of diamond

Strong covalent bonds in all directions

What is diamond's melting point?

3350 degrees celcius

Why are nanotubes used in catalyst systems?

Atoms of the catalyst can be attached to the nanotube's large surface area.