Flashcards for OCR 21st Century Science C6

Quick revision for C6- chemical synthesis.

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  • Created by: isis
  • Created on: 17-01-13 19:11
What does acid + alkali give you?
Salt and water
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How else can a neutrslisation reaction be seen?
H+ + OH- = H2O
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What does acid + metal give you?
Salt and Hydrogen
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True or false: the more reactive the metal the faster the reaction?
True
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How is the speed of the acid + metal reaction shown?
Rate at which hydrogen bubbles are give off.
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What does the name of the salt depend on?
Which metal and which acid is used
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What does acid + metal oxide give you
Salt and water
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What does acid + metal hydroxide give you?
Salt and Water
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What reaction is a metal oxide or hydroxide and acids an example of?
Neutralisation Reaction
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What does acid+ metal carbonate give you?
Salt and Water and Carbon Dioxide
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Describe chemical synthesis
1 Choosing the reaction, 2 Risk assessment, 3 Calculating quantities, 4 choosing apparatus and conditions, 5 isolating the product, 6 purification, 7 measuring yield and purity
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Name purification methods?
Filtiration, Evaporation and Crystallisation, Drying
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what is the formula for yield
% yield= (actual yield/ theoretical yield) x 100
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What is used in a titration?
Burette, titration flask, acid and alkali with indicator
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Why do pharmaceuticals need to be pure?
They are intended for human consumption and so need to be pure as impurities may do more harm than good
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Why do petrochemicals need to be pure?
If there are impurities or contaminants in petrol products they could cause damage to a car's engine.
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What can titrations be used for?
To meaure the purity of a substance
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What is an exothermic reaction?
One the gives out energy to the surroundings usually in the form of heat and usually shown by a rise in temoperature
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What is an endothermic reaction?
One which takes in energy from the surroundings usually in the form of heat and usually shown by a fall in temperature.
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Why do scientist in the chemical industry need to know how much energy is taken in?
If it is exothermic then heat needs to be provided or the reactants might become too cold, and so slow the rate of reaction or cause it to freeze. whiuch could damage equipment and stop the whole process
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Why do scientist in the chemical industry need to know how much energy is taken in?
If it is endothermic then heat needs to be provided or the reactants might become too cold, or slow the rate of reaction or cause it to freeze. Which could damage equipment and stop the whole process.
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what is the rate of reaction?
How fast the reactants are changed into products.
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Give an examples of one of the slowest reactions?
The rusting of iron, chemical weathering.
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Give an example of a moderate speed reaction?
A metal reacting with an acid to produce a gentle stream of bubbles.
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Give and example of a fast reaction?
Burning, explosions
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Why is it important to control the rate of a reaction?
Safety and Economic reasons
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What does the rate of reaction depend on?
Temperature, Concentration, Catalyst and Surface Area.
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Why does increasing the temperature increase the rate of reaction?
The particles are move faster so are more likely to collide. also they have more energy so more particles will have enough energy to make the reaction happen.
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Why does increasing the concentration increase the rate of reaction?
If a solution is more concentrated then it means there are more particles of the reactants in the same volume of the water. so collisions are more likely to happen.
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Why does increasing the surface area increase the rate of reaction?
The particles will have more area to work on so collisions will be more frequent.
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What is a catalyst?
it is a substance which increases the rate of reaction without being changed or used up in the reaction.
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Why does using a catalyst increase the rate of reaction?
The reacting particles have a surface to stick on where they can bump into each other - increasing the number of successful collisions
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What is the formula for rate of reaction?
Amount of reactant used or amount of product formed/ time
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What are the three ways of measuring rate of reaction?
1 precipitation and colour change 2 change in mass (usually gas given off) 3 the volume of gas given off
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Other cards in this set

Card 2

Front

How else can a neutrslisation reaction be seen?

Back

H+ + OH- = H2O

Card 3

Front

What does acid + metal give you?

Back

Preview of the front of card 3

Card 4

Front

True or false: the more reactive the metal the faster the reaction?

Back

Preview of the front of card 4

Card 5

Front

How is the speed of the acid + metal reaction shown?

Back

Preview of the front of card 5
View more cards

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