Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemisty > C3a > Flashcards

C3a Flashcards

(71 cards)

Start Studying
1
Q

Do you get scum with hard or soft water?

A

Hard water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What dissolved ions does hard water contain?

A

Magnesium ions and calcium ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens when hard water is heated?

A

It forms furring or scale (mostly calcium carbonate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does hard water do to the inside of pipes, boilers and kettles?

A

Scale likes the inside of pipes reducing the efficiency of heating systems and eventually blocking pipes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does scale do to heating elements on a kettle?

A

It acts as a thermal insulator meaning the heating element takes longer to beat up and boil water. Therefore it is less efficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does rainwater become hard water?

A

It falls on some types of rocks (limestone, chalk and gypsum) which means magnesium sulfate and and calcium sulfate get dissolved into the water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is magnesium sulfate soluble?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is calcium sulfate soluble?

A

Yes, but only a little bit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is good for healthy teeth and bones?

A

Ca2+ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are people who live in hard water areas at less risk of than people who live in soft water areas?

A

Developing heart disease. It could be to do with the minerals in hard water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Two types of hard water

A
  • Temporary hard water

- Permeant hard water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is temporary hard water caused by?

A

The hydrocarbonate ion HCO3- in Ca(HCO3)2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is permanent hard water caused by?

A

Dissolved calcium sulfate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is temporary hardness removed?

A

By boiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does boiling temporary hard water do?

A

It causes the calcium hydrocarbonate to dissolve to form calcium carbonate, which is insoluble (this is limescale)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When calcium hydrogencarbonate is heated what does it produce?

A
  • Calcium carbonate
  • Water
  • Carbon dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens when Ca(HCO3)2(aq) is heated? What is produced?

A
  • CaCO3(s)
  • H2O(l)
  • CO2(g)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens when you boil permanent hard water?

A

Heating a sulfate ion does nothing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do you soften both types of hard water?

A

You add washing soda (sodium carbonate Na2CO3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens when sodium carbonate is added to hard water?

A

The added carbonate ions react with the Ca2+ and Mg2+ ions to make an insoluble precipitate of calcium carbonate and magnesium carbonate. The Ca2+ and Mg2+ ions are no longer dissolved so they can’t make it hard

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How can both types of hardness be removed?

A

By running the hard water through an ‘ion exchange column’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do ion exchange columns work?

A

The columns have lots of sodium or hydrogen ions which ‘exchange’ them for calcium or magnesium ions as the water runs through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does most of our drinking water come from?

A

Reservoirs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Microbes in water cause what diseases?

A

Cholera and dysentery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Where does the water in reservoirs come from?
Rivers and groundwater
26
Water treatment process
- Water travels through mesh screen (to remove big stuff e.g. twigs) - Chemicals are added to make solids and microbes stick together then fall to the bottom - The water is filtered through gravel beds to remove solids - the water is chlorinated to remove harmful microbes
27
What are in water filters that people buy?
Carbon to remove chlorine taste and silver to kill bugs
28
Why is fluorine added to drinking water?
It is added in some parts of the country to reduce tooth decay
29
Why is chlorine added to drinking water?
To prevent diseases
30
Disadvantages of adding chlorine to drinking water
It can react with other natural substances in water to produce toxic by-products which some people believe could cause cancer
31
What can be caused by high doses of fluoride?
Cancer and bone problems
32
Define reversible reactions
A reaction where the products of the reaction can themselves react to produce the original reactants
33
What will happen if the reversible reaction happens in a closed system?
A state of equilibrium will always be reached
34
What a reaction reaching equilibrium mean?
That they reactions are taking place in both directions but the overall effect is zero as they cancel each other out. the reactions happen at the same rate
35
The general formula for an alcohol
CnH2n+1OH
36
what is a homologous series?
A group of chemicals that react in a similar way because they have the same functional group
37
What is the functional group of alcohols?
OH
38
Properties of alcohols
- flammable, burn in air to produce carbon dioxide and water - The first three completely dissolve in water to produce neutral solutions - They react with sodium to give hydrogen and alkoxides
39
What happens if you raise the temperature in a reversible reaction?
The endothermic reaction will increase and increase the yield
40
What happens if you decrease the temperature in a reversible reaction?
The exothermic reaction will increase increasing the yield
41
What happens if you raise the pressure in a reversible reaction?
The reaction which produces less volume will be encouraged
42
What happens if you decrease the pressure of a reversible reaction?
It will encourage the reaction which produces more volume
43
If you add a catalyst to a reversible reaction what will happen to the equilibrium position?
It won't change
44
What does a catalyst do to a reversible reaction?
It speeds up both the forward and backward reactions by the same amount
45
How does adding a catalyst change the overall yield in a reversible reaction?
The yield is the same however you would reach equilibrium faster
46
In the haber process where is nitrogen obtained from?
The air (which is 78% nitrogen and 21% oxygen)
47
Where does the hydrogen come from for the haber process?
It comes from natural gas or other sources like crude oil
48
What happens when nitrogen is reacted with hydrogen?
It reacts to form ammonia
49
Is the haber process reversible?
Yes it is nitrogen and hydrogen react to form ammonia then ammonia breaks down again into nitrogen and hydrogen
50
The industrial conditions of the haber process - Pressure - Temperature - Catalyst
- Pressure - 200 atmospheres - Temperature - 450degreesC - Catalyst - Iron
51
What is the equation of the haber process?
N2(g) + 3H2(g) <=> 2NH3(g)
52
What does increasing the pressure do to the haber process?
It favours the forward reaction (as there are 4 molecules of gas on the left and 2 on the right)
53
What is the pressure set for the haber process? Why?
-200atm It is as high as possible to give the highest % yield without being too expensive (to build a plant to withstand really high pressures)
54
What is the forward reaction in the haber process? Exothermic or endothermic?
Exothermic
55
What happens if you increase the temperature in the haber process?
The equilibrium will move the wrong way. Away from ammonia and towards nitrogen and hydrogen
56
To increase the yield of ammonia would you increase of decrease the temperature?
Decrease
57
Lower temperatures mean a lower rate of reaction so what do they do to the haber process?
They increase the temperature anyway to get a faster rate of reaction
58
Why do people use a temp of 450degreesC in the haber process?
It is a compromise between maximum yield and speed of reaction. It's better to wait 20 seconds for a 10% yield than 60 seconds for a 20% yield
59
What state is the ammonia field in?
A gas but then it is cooled in the condenser, it then liquifies and is removed
60
What happens to the unused hydrogen and nitrogen at the end of the haber process?
They are recycled back into the process so nothing is wasted
61
What ratio is the hydrogen to nitrogen in the haber process?
3:1
62
What does the iron catalyst do to the haber process?
It makes to reaction go faster and it gets to the equilibrium proportions faster. But the catalyst does not affect to position of equilibrium (% yield)
63
What would have to be done if the haber process did not use a catalyst?
The temperature would have to be increased to get a quick enough reaction but this would reduce the % yield
64
What is the main alcohol in alcoholic drinks and why?
Ethanol - it is not as toxic as methanol (which causes blindness) but it still causes liver and brain damage
65
Why are ethanol, methanol and propanol useful solvents in industry?
They can dissolve most compounds that water dissolves, but they also dissolve substances that water can't dissolve (hydrocarbons, oils and fats)
66
What is the solvent used for perfumes, aftershave lotions? Why?
Ethanol - it mixes with both oils (which give the smell) and the water (that makes up the bulk)
67
What is 'methylated spirit' (or 'meths')?
It is ethanol with chemicals (e.g. methanol) added to
68
What are 'methylated spirits' used for?
They are used to clean paint brushes and as fuel
69
Why is purply-blue dye added to 'methylated spirit'?
To stop people drinking it as it is poisonous
70
Which alcohol is used as a fuel in spirit burners? Why?
Ethanol as it burns fairly cleanly and its non smelly
71
Which alcohol is mixed with petrol for fuel for cars and why?
Ethanol because it is clean burning, the more ethanol in a petrol/ethanol mix the less pollution is produced

Chemisty (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions