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Chemistryyy > Chemsitry - Equillibrium > Flashcards

Chemsitry - Equillibrium Flashcards

1
Q

If the forward reaction is ? (transfers energy from ? to the environment), the ? reaction will be endothermic (transfers ? from the ? to the reactants).

A

exothermic, reactants, backwards, energy, surroundings

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2
Q

The energy released/? by the forward ? will be exactly ? to the energy absorbed/? by the ? reaction

A

absorbed, reaction, equal, released, backwards

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3
Q

The concentrations of ? and products do ? change when a reaction is at ? equilibrium

A

reactants, not, dynamic

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4
Q

what will eventually be reached when reversible reactions happen within a closed system

A

Dynamic equilibrium

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5
Q

At dynamic equilibrium, how are the rates of the forwards and backwards reactions related?

A

they’re equal

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6
Q

why is equilibrium dynamic?

A

because both the forwards and backwards reactions are still taking place

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7
Q

what happens at equilibrium?

A

the rate of the forward reaction equals the rate of the backward reaction

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8
Q

how can the position of equilibrium be affected?

A

by changing the conditions in a reversible reaction

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9
Q

Le ? principle says that if any of the conditions of a ? reaction at equilibrium are changed, the ? system will ? to counteract whatever has ?

A

Chatelier’s, reversible, closed, adapt, changed

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10
Q

what can Le Chatelier’s principle be used for?

A

to predict the outcome of changes imposed on a system at equilibrium

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11
Q

what determines the relative amount of the substances involved in a reaction at equilibrium?

A

the conditions of the reaction

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12
Q

what does changing the temperature for a reaction at equilibrium do and what does the system do in response?

A

takes the system out of equilibrium. in response the system will try and restore equilibrium

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13
Q

what happens when the temperature decreases in equilibrium? (and what happens to the products)

A

the position of equilibrium shifts in the exothermic direction - meaning more products from exothermic reaction and less from endothermic reaction

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14
Q

what happens if there’s an increase in temperature in equilibrium and what happens to the products?

A

the position of equilibrium shifts in the endothermic direction - meaning more products from endothermic reaction and less from exothermic reaction

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15
Q

The position of equilibrium will shift towards the side of the reaction that produces the most gas molecules - when does this happen?

A

when the pressure is decreased

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16
Q

what happens at equilibrium if you increase the pressure?

A

the position of equilibrium will shift to favour the reaction that produces the least/ fewest gas molecules

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17
Q

how do we predict the outcome of a pressure change?

A

have to look at balanced equations to see how many gas molecules are on each side of the equation!!!

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18
Q

what does changing the concentration of any reactant or product do?

A

takes the system out of equilibrium. The system will react to try to restore the equilibrium

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19
Q

what does increasing the concentration of a reactant do?

A

favours the forward reaction - shifting the position of equilibrium towards the products

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20
Q

what happens if you increase the concentration of a product?

A

favours the backward reaction - shifting the position of equilibrium towards the reactants

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21
Q

what’s the backwards reaction?

A

when the equilibrium shifts towards the reactants

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22
Q

what’s the forwards reaction?

A

when equilibrium shifts towards the products

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23
Q

what’s the forwards reaction?

A

when equilibrium shifts towards the products

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24
Q

What happens when you increase the concentration of a product of a reversible reaction at equilibrium? (rate of reaction)

A

Rate of forwards reaction < rate of backwards reaction

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25
Q

What happens when you increase the concentration of a reactant of a reversible reaction at equilibrium?

A

Rate of forward reaction > rate of backwards reaction

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26
Q

ph of ammonia solution?

A

11

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27
Q

equation of the reversible reaction between ammonia and water

A

NH3 +H2O ⇌ NH4+ + OH-

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28
Q

what are the properties of ammonia and why?

A

low melting point, non conductive, gas at room temperature - this is because of its weak intermolecular forces between molecules, and there are no delocalized electrons for conduction

29
Q

what do catalysts do?
speed up the (?) ? without being used ?. they work by providing an ? route/ ? with lower ? energy. they do not affect the ? of equilibrium, as they speed up both the ? and the reverse/? reactions by the same ?. however, they do ? up the rate at which ? is reached.

A

(chemical) reaction, up, alternative, pathway, activation, rate, forward, backward, amount, speed, equilibrium

30
Q

3 steps of answering equilibrium questions:
1. state whether the ? of equilibrium has shifted ? or right
2. state why, e.g. endothermic or ? direction, more/? gas ? etc
3. state that this ? the change of ?/decreasing temp/?

A

position, left
exothermic, less, particles
opposes, increasing, pressure

31
Q

what does Le Chatelier’s principle state?

A

When a change is made to a reaction in equilibrium, the position of equilibrium will shift to oppose the change.

32
Q

what may fertilisers contain to promote plant growth?

A

nitrogen, phosphorus and potassium compounds

33
Q

what are the 3 conditions for the Haber process?

A
  • temperature - 450 degrees
  • pressure - 200 atmospheres
  • iron catalyst!
34
Q

what is dynamic equilibrium?

A

when the forwards and backwards reactions are equal and still taking place in a reversible reaction!!

35
Q

what is ammonia formed from and how are these gases extracted?

A

nitrogen (from the air) and hydrogen (from natural gas)

36
Q

why can the reaction of nitrogen and hydrogen to form ammonia reach dynamic equilibrium?

A

as it is a reversible reaction.

37
Q

chemical formula of ammonia and its bonding type???

A

NH3, covalent bonding

38
Q

what 3 things is ammonia used to make?

A

Fertilisers, plastics, explosives

39
Q

How is ammonia separated from unreacted chemicals?

A

Let it cool to -40 degrees - so ammonia will liquefy and run out the bottom, while nitrogen and hydrogen will remain as gases

40
Q

What happens to the unreacted nitrogen and hydrogen in the haver process?

A

Recycled back into the reaction vessel

41
Q

How to produce nitrogen from air?

A

Fractional distillation of liquid air - separates oxygen and nitrogen by boiling points

42
Q

what conditions give the highest % of ammonia?

A

high pressure and low temperature

43
Q

what is negative about using high pressures in the haber process

A

very expensive to build and run the plant and is also dangerous

44
Q

Why is 450 degrees and 200ATM used in the haber process

A

Is a compromise of temp - as it gives a medium rate with medium yield
A compromise of pressure as it is less expensive but still gives a relatively good yield

45
Q

Two reasons why the low yield in the haber process is NOT a problem?

A

Fast rate of reaction so yield achieved quickly
Reactants are recycled so no wasted H2 or N2

46
Q

Why is nitrogen a gas at room temp ans why is it so UNreactive

A

Simple molecular - weak intermolecular forces require little energy to break
Has a triple bond so requires a lot of energy to break

47
Q

Why are harmful NOx gases produced in a car engine

A

Car engine is very hot + gas is under v high pressure so reacts with oxygen

48
Q

What do most plants require to supply their nitrogen intake

A

Soluble nitrogen compounds

49
Q

What are natural sources of nitrogen compounds and why are they nit sufficient enough?

A

Manure and compost, but there’s not enough to support the earths growing temperature

50
Q

Why can’t ammonia be used as a nitrogen fertilizer and what is the solution to this?

A

As it is alkaline and easily escapes from the soil as a gas, but it can be made into a suitable fertilizer by reacting it with an acid

51
Q

How is the reaction of acid and ammonia different from other Neutralisation reactions?

A

It doesn’t produce water, just the ammonium salt

52
Q

Why are ammonium salts better than ammonia as fertilizers (3 reasons) :

A
  1. Not alkaline, are neutral
  2. Less toxic
  3. Not gases
53
Q

Explain how to make a pure, dry sample of ammonium solution and nitric acid?
(Titration!)

A
  1. Use a glass Pipette to add 25cm3 of ammonia to a comical flask
  2. Add a few drops of methyl orange to turn it yellow
  3. Add nitric acid from burrette
    —> swirl
    —> add dropwise near end
  4. Add end point methyl orange should go a (peachy) orange
  5. Repeat using same volumes but no indicator
  6. Evaporate water away by heating
  7. Leave to cool and crystallize
  8. Remove crystals by filtration
54
Q

What is Phosporus (P) used for in crops

A

DNA, growth, healthy roots

55
Q

What is Potassium (K) used for in crops

A

Fruiting and flowering

56
Q

What is Nitrogen (N) used for in crops

A

Amino acids, proteins, DNA

57
Q

Difference in scale of laboratory vs industrial manufacture of fertilizers?

A

L - milligrams
I - tonnes

58
Q

Difference in safety of laboratory vs industrial manufacture of fertilizers?

A

L - safe due to low concentration
I - dangerous due to high pressure and concentration

59
Q

Difference in equipment of laboratory vs industrial manufacture of fertilizers?

A

L - glassware
I - thick stainless steel container

59
Q

Difference in conditions of laboratory vs industrial manufacture of fertilizers?

A

L - room temp and pressure
I - 60 degrees, high pressure

60
Q

Difference in type of process of laboratory vs industrial manufacture of fertilizers?

A

L - batch
I - continuous (flow)

61
Q

How would an increase in the price of natural gas affect the price of fertilizer?

A

Increases the price, as natural gas is needed to make hydrogen which is used in the haben process to make ammonia

62
Q

Which compound - ammonium nitrate or sulfate would be a better value for a nitrogen fertilizer?

A

Ammonium nitrate as it has a higher percentage by mass of nitrogen (35% vs 21.21%) so it’s better value for money!!!

63
Q

Why is potassium Phosphate called a P.K fertilizer?

A

As it is a compound containing both phosphorus and potassium

64
Q

Name and formula of a compound which would be an N.K fertilizer???

A

KNO3 - potassium nitrate

65
Q

Ammonium phosphate is an N.P fertilizer. Give the word and Symbol equation for its production..?

A

NH3 + H3PO4 —> (NH4)3PO4
Ammonia + phosphoric acid —> ammonium phosphate

65
Q

Drawback of fertilizers?

A

Eutrophication- nutrients accumulate, leading to an excess in microorganisms , leading to a decreased amount of oxygen supply in water

66
Q

Steps of eutrophication:
1. ? washed into ? / canals
2. Algae ? and covers surface of ?
3. Sunlight is unable to reach ?
4. Plants ?, so less ? in water
5. Aquatic animal ? dies as there isn’t ? O2
6. Dead, ? stretch of water

A
  1. Fertilizers, rivers
  2. grows, water
  3. plants
  4. die, O2
  5. life, enough
  6. stinking

Chemistryyy (47 decks)

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