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Chemistry GCSE > Topic 6 - Quantitive Analysis, Dynamic Equilibria, Calcularions Involving Volumes Of Gases, Chemical Cells and Fuel Cells > Flashcards

Topic 6 - Quantitive Analysis, Dynamic Equilibria, Calcularions Involving Volumes Of Gases, Chemical Cells and Fuel Cells Flashcards

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1
Q

actual yeild

A

The amount of product obtained when you carry out experiment

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2
Q

Percentage yield equation

A

percentage yield = (actual yield / theoretical yield) x100

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3
Q

reasons why the yield is less than expected

A
  • reaction may be incomplete so not all the reactants are used up - possibly because the reaction has not been left for long enough or the reaction may reach equilibrium
  • some of the products are lost
  • there may be other unwanted side reactions taking place
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4
Q

atom economy

A

mass of the product you want as a % of the mass of all the products you make

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5
Q

atom economy equation

A

atom economy = (Relative formula mass of useful product /sum of relative formula masses of all the reactants) x 100

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6
Q

% yeild

A

amount of product you actually make as a % of the amount you should theoretically make

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7
Q

% yeild

A

amount of product you actually make as a % of the amount you should theoretically make

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8
Q

How do you make a solution?

A

The solid is dissolved in distilled water and then made up to graduation mark before suffering and then shaking the flask

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9
Q

Concentration of a solution

A

The amount of solute dissolved in a state volume of solution

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10
Q

In centimetres cubed, how much is 1 decimetre cubed?

A

1000cm3 = 1dm3

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11
Q

How do you work out concentration in g/dm3?

A

concentration in g/dm3 =0.0164 g/in² mass of solute in g / volume of solution in dm3

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12
Q

how do u work out concentration in mol/dm3 (2 equations)

A

concentration in mol/dm3 = number of moles of solute / volume of solution in dm3

concentration in mol/dm3 = concentration in g/dm3 / RFM of solute

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13
Q

Acid-alkali Titration

A

Used to find the exact volume of an acid that neutralises a fixed volume of alkali or vice versa

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14
Q

method for an acid-alkali titration (CORE PRACTICAL)

A
  1. Rise a burette with hydrochloric acid to fill the burette with the acid
  2. Record initial volume of the acid in the burette
  3. Rinse pipette with sodium hydroxide solution then fill the pipette to the 25.0cm3 mark and empty the solution in a conical flask
  4. Add a few drops of methyl orange indicated to the flask on a white tile underneath the burette
  5. At the acid to the sodium hydroxide solution while swirling the flask
  6. When the indicator starts to change colour in the tip of the bureau and the sides of the floss with a small amount of distilled water from a wash bottle to ensure that all the acid is in the mixture and add the acid drop by drop until the end point is reached.
  7. Record the final volume of acid in the burette
  8. Repeat the experiment apart from the initial rinsing of the bureau and paper until concordant results are obtained.
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15
Q

concordant result

A

if the results are within 0.2cm3 of each other

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16
Q

End point

A

The point at which the indicator changes colour in an acid- base titration

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17
Q

Avogadros Law

A

If the temperature and pressure are the same equal volume of different gases contain an equal number of molecules?

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18
Q

Molar gas volume

A

The volume occupied by one mole of molecules of any gas (24dm3 at room temp and pressure)

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19
Q

amount of gas equation (at rtp)

A

moles of gas = volume of gas (dm3) / 24

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20
Q

How is ammonia manufactured?

A

Through the Haber process

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21
Q

Haber process

A

Process in which nitrogen and hydrogen reacts together in a reversible reaction

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22
Q

ammonia symbol equation

A
23
Q

What conditions are used in the Haber process?

A
  • 450°C
  • 200 atmospheres pressure
  • iron catalyst
24
Q

What conditions are used in the Haber process?

A
  • 450°C
  • 200 atmospheres pressure
  • iron catalyst
25
Q

What happens to the equilibrium position when temperature is increased?

A

The equilibrium position shifts in the direction of the endothermic reaction

26
Q

What happens to the position of equilibrium if pressure is increased in a reaction involving gases?

A

The position of equilibrium moves towards the side of the balanced equation with the fewer molecules of reacting gas

27
Q

What happens to the position of equilibrium if the concentration of a reacting substance increases?

A

The position of equilibrium moves away from the reacting substance in the balance equation

28
Q

What factors affect equilibrium?

A
  • temp.
  • pressure
  • concentration
29
Q

When making ammonia is the forward reaction exo or endothermic

A

Exothermic

30
Q

When making ammonia is the backward reaction exo or endothermic

A

Endothermic

31
Q

When making ammonia why is it at 450°C?

A

Because low temperatures increase the equilibrium yield of ammonia but reduces the rate of reaction so 450°C is a compromise that gives an acceptable yield of ammonia in an acceptable time

32
Q

When making ammonia, why is it done at 200 atmospheres (pressure)?

A

High pressures increase equilibrium of ammonia and increase the rate of reaction so 200 atm is a compromise because it’s very high pressure too expensive to maintain

33
Q

When making ammonia, why is there an iron catalyst?

A

Because it does not change position of equilibrium, but it does increase the rate of reaction

34
Q

How is your reaction pathway chosen - what factors does it take into account?

A
  • Availability and cost of raw materials and energy supplies
  • The rate of reaction and the equilibrium position
  • Atom economy, yield and usefulness of byproducts
35
Q

What is a byproduct?

A

An accidental or secondary product made in the manufacture of synthesis or something else

36
Q

What components does a chemical cell contain?

A
  • Two different metals each dipped into a solution of one of their salts
  • a ‘salt bridge’ to allow dissolved ions to pass from one solution to another
37
Q

What does it mean to the voltage if the two metals are further apart in the reactivity series? (Chemical cell)

A

The voltage is greater when the two metals are further apart in the reactivity series

38
Q

What three elements do plants need to grow well?

A
  • Nitrogen, phosphorus and potassium
39
Q

Artificial fertilisers (NPK fertilisers)

A

chemical compounds which contain these elements - they need to be soluble so that the ions dissolve and are easily absorbed by plant

40
Q

How are ammonium salts made?

A

A neutralisation of ammonia with acids

41
Q

Haber process diagram

A
42
Q

What ammonium salts are used as fertilisers?

A
  • Ammonium sulphate and ammonium nitrate
43
Q

What is a batch process?

A

A method of completing tell us all the groups or a lot rather than individually or in real time

44
Q

What do fertilisers do?

A

They replace the mineral ions needed by plants and so promote plant growth

45
Q

hydrogen fuel cells

A

are electrochemical devices like batteries, which produce electricity by converting hydrogen and oxygen into water

46
Q

Fuel cell

A

Electricity produced when they are supplied with fuel and oxygen from outside

47
Q

What happens at each electrode in a hydrogen-oxygen fuel cell?

A
  • hydrogen atoms lose electrons and form hydrogen ions
  • electrons flow through the external circuit to the positive electrode (anode)
  • hydrogen ions pass through a membrane to the right hand side electrode where they gain electrons and react with oxygen to produce water
48
Q

How do you calculate the theoretical yield?

A

Calculate the relative formula masses and a multiplied by the balancing number (total RFM)

49
Q

What are the two methods of making ethanol

A
  • fermentation
  • Reaction of ethene w steam
50
Q

Compare fermentation and reaction of ethene with steam

A
51
Q

What is a continuous process?

A

A process in which reactants are constantly fed into the reactors and products are removed

52
Q

Advantages of continuous process

A

+ automated - need fewer people to make a given amount of product

53
Q

daniell cell

A

an electrochemical cell that converts chemical energy into electrical energy

54
Q

How is hydrogen mostly manufactured?

A

by the reaction of steam with coal or natural gas -> these processes do release carbon dioxide as a byproduct

Chemistry GCSE (8 decks)

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