Chemistry Flashcards C2 Part 2

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  • Created by: Abbie
  • Created on: 15-05-13 09:36
What are the 4 factors that affect the rate of a reaction?
1)Temperature 2)Concentration/(pressure for gases) 3)Catalyst 4)Surface area of solids
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What are the 3 different ways of measuring the rate of a reaction?
1)Precipitation 2)Change in mass (usually gas given off) 3)The volume of gas given off
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Explain how: a)higher temperature & b)larger surface area increase the frequency of successful collisions between particles.
a)Temperature increases causing the particles to move quicker and collide more often. b)Breaking up a solid into smaller pieces increases SA. Therefore the particles around it in solution will have more area to work on= more collisions.
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Explain how: a)Higher concentration & b)Increase in Pressure increase the frequency of successful collisions between particles.
a)Solution is more concentrated therefore more particles of reactant knocking about between the water molecules therefore more collisions. b)(Gas) An increase in pressure means the particles are more squashed up together so more collisions.
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What is the definition of a catalyst?
A substance which speeds up a reaction, without being changed or used up in the reaction.
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What is activation energy?
The minimum amount of energy needed by particles to react is known as the activation energy.
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What are the advantages of using catalysts in industrial processes?
1)Catalysts increase the rate of reactions, therefore quicker so saves money. b)Work at a lower temperature=reduces energy used up=save money (good for sustainable development).
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What are the disadvantages of using catalysts in industrial processes?
a)Expensive to buy b)often need to be removed from product & cleaned c)Different reactions use different catalysts, so if you have more than one product, youll need to buy different catalysts. c)Catalysts can be 'poisoned' by impurities=stop working
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What is an Exothermic reaction? and an example.
One which transfers energy to the surroundings, usually in the form of heat and usually shown by a rise in temperature. EXAMPLE- Combustion (burning fuels), neutralisation & oxidation reactions.
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What are some everyday uses of exothermic reactions?
a)Hand warmers- they use the oxidation of iron in air to generate heat. b)Self heating cans- rely on exothermic reactions between chemicals in their bases.
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What is an Endothermic reaction? and an example.
One which takes in energy from the surroundings, usually in the form of heat and is usually shown by a fall in temperature. EXAMPLE- thermal decompositions.
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What is an everyday use of endothermic reactions?
Sports injury packs-they take in heat and the pack becomes very cold.
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What does the pH scale show?
How acidic or alkaline a solution is. The strongest acid= pH 0 & The strongest alkali= pH 14.
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What type of ions are always present in: a)acids and b)alkalis?
a)H+ ions b)OH- ions
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a)What is the reaction for neutralisation? b)in terms of ions?
a) acid+base--> salt+water b)H+ + OH- --> H2O
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What does (aq) stand for?
Aqueous- which means dissolved in water.
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What is the general equation for reacting an acid with a metal?
acid+metal --> salt+hydrogen
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Name a metal that doesn't react at all with dilute acids? Why?
Copper because it's less reactive than hydrogen.
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Why is Ammonium nitrate a good fertiliser? And what 2 sources does nitrogen come from?
It contains nitrogen which is needed for plant growth & to make proteins. Nitrogen comes from the ammonia and the nitric acid.
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Give 2 practical uses of precipitation reactions
1)Can be used to remove poisonous ions from drinking water. 2)Can be used in treating sewage (removing unwanted ions)
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a) What is one industrial use of sodium hydroxide? b)and two uses of chlorine?
a)Sodium hydroxide is a very strong alkali and is used widely in the chemical industry (eg. to make soap). b)In the production of bleach and plastics.
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Why is cryolite used during the electrolysis of aluminium oxide?
Cryolite is used to lower the temperature, which makes it cheaper and easier.
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What are 2 different uses of electroplating?
1)Decoration: Silver is attractive, but expensive. So its cheaper just to coat the cup than make the cup out of solid silver. 2)Conduction: Metals conduct electricity well, so theyre used to plate metals for electronic circuits & computers.
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a) What is reduction? b)What is oxidation?
a) Reduction is the gain of electrons (but loss of oxygen). b)Oxidation is the loss of electrons (but gain of oxygen).
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Other cards in this set

Card 2

Front

What are the 3 different ways of measuring the rate of a reaction?

Back

1)Precipitation 2)Change in mass (usually gas given off) 3)The volume of gas given off

Card 3

Front

Explain how: a)higher temperature & b)larger surface area increase the frequency of successful collisions between particles.

Back

Preview of the front of card 3

Card 4

Front

Explain how: a)Higher concentration & b)Increase in Pressure increase the frequency of successful collisions between particles.

Back

Preview of the front of card 4

Card 5

Front

What is the definition of a catalyst?

Back

Preview of the front of card 5
View more cards

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