Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chem > Chemistry > Flashcards

Chemistry Flashcards

(99 cards)

Start Studying
1
Q

What percentage is there of nitrogen in the air

A

78%

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

What percentage is there of argon in the air

A

0.9%

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

What percentage of co2 is there in the air

A

0.037%

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

What is wrong with the oxygen percentage test in which copper is heated up

A

There is air between the copper and the air in the gas syringe expands due to an next ease in temperature

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

How was the earths early atmosphere formed

A

Volcanic activity

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

What was the consistency of the earths early atmosphere

A

Mostly carbon dioxide

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

How many billion years was there intense volcanic activity to form the earths early atmosphere

A

1 billion

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

What gases other than co2 probably existed in the early atmosphere

A

Water vapour, ammonia, methane

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

How did the oceans get formed

A

The water vapour in the early atmosphere condensed because the earth cooled

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

Which to planets are believed to have early similar atmospheres compared to the early atmosphere of earth

A

Mars and Venus as their atmospheres consist mainly of carbon dioxide

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

Of they weren’t there how can scientists know the consistency o the early atmosphere

A

Scientists had to gain information from other sources for example:
Volcanoes on other planets release high quantities of carbon dioxide

Nitrogen and iron compounds present in very old rocks that could only have formed in an ocygen free environment

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

How did the proportions of oxygen in the early atmosphere go up and the proportion of carbon dioxide go down

A

The proportion of oxigen went up because of photosynthesis by plants

Carbon dioxide went down because:
It was locked up in sedimentary rocks like limestone, and in fossil fuels like oil

It was absorbed by plants for photosynthesis

It dissolved in oceans

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

How is the level of the current atmospheres co2 increasing

A

We are burning fossil fuels and adding co2 into the air faster than it can be removed

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

How is the level of carbon dioxide maintained

A

Photosynthesis
Green plants all remove co2 from the air through photosynthesis

Combustion
Releases co2 into the air

Respiration
Releases co2 into the air

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

Steps of the carbon cycle

A

Respiration and combustion out co2 into the air

Photosynthesis takes co2 out of the air

Animals eat plants and release co2 back into the air

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

Ways humans are increasing the atmospheres co2 content

A

With more people we burn more fossil fuels for energy

When land is cleared for timber and farms there are fewer trees to remove co2 this is extra bad when we clear trees for farmland by burning them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

One does not always get the calculated amount of product from a reaction because;

A

Reversible reactions may not go to completion

Some products may be lost when it’s removed from the reaction mixture

Some of the reactants may react in an unexpected way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is an example of conservation of mass

A

A precipitation reaction

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

Why is it easy to show conservation of mass in a precipitation reaction

A

All the reactants and products remain in the same sealed reaction container so it is easy to show the mass has not changed

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

What is copper sulphate

A

CuSO4

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

What is sodium hydroxide

A

NaOH

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

What colour precipitate does iron (II) produce

A

Green- turns brown when standing

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

What colour precipitate does iron (111)

Produce

A

Orangy brown

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

What colour precipitate does copper produce

A

Blue pale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What colour precipitate does zinc produce
White
26
4 features of acids
Have a low ph (1-6) React with bases to form neutral compounds Are corrosive when strong Are irritant when weak
27
What is an indigestion remedy
An indigestion remedy contains a base like magnesium hydroxide which reacts to form a neutral compound and raises the oh of the stomach
28
What do you observe during a metal hydroxide and acid reaction
Temperature rise The ph changes
29
What are the products in a metal hydroxide plus acid reaction
A salt and water
30
Are metal hydroxides soluble
Yes- they usually dissolve in water to form clear colour less solutions
31
Are metal oxides usually soluble
No but some of them such as sodium oxide can dissolve in water to form clear colourless solutions
32
What are the products of a metal oxide plus acid reaction
Salt and water
33
What can you observe during a metal oxide and acid reaction
Temperature rise and ph change
34
Are metal carbonates dissolve in water
No but sodium carbonate can (bicarbonate of soda) just remember that in both metal oxides and metal carbonates sodium is one of the only ones that dissolves
35
What are the products of a metal carbonate and acid reaction
A salt Water Carbon dioxide
36
What can you observe in an acid plus metal carbonate reaction
Bubbles being given off (co2) A ph change
37
When hydrochloride acid reacts with a metal hydroxide carbonate etc is an ate or ide formed
It is always an Ide
38
When sulphuric acid reacts with an oxide hydroxide etcetera does it form an ate or an IDE
Always ate
39
What is electrolysis
Electrolysis is the process in which ionic substances are broken down into simpler substances using electricity. During electrolysis, metals and gases may form at the electrodes.
40
What is an ionic compound
The product of When a metal reacts with a non metal
41
What must the ions be to perform electrolysis
Free to move one does this by either dissolving the substance in water or melting it
42
How does electrolysis work
Positively charged ions move towards the negative electrode during electrolysis and receive electrons to turn them into their original form Negatively charged ions move toward the positively charged electrode they lose electrons to form their original state and are oxidised
43
4 facts about the electrolysis of hydrochloric acid
Produces chlorine at the positive electrode | Produces hydrogen at the negative electrode
44
How to test for chlorine
Turns damp blue litmus paper red then white
45
The products of the electrolysis of water
Hydrogen at the negative electrode | Oxygen at the positive electrode
46
What percentage is the oxygen in the air
21%
47
What is reduction
The loss of oxygen from a substance many ores are oxides so one can extract metals through reduction
48
How do we extract very reactive metals compared to less reactive metals
The oxides of very reactive metals such as aluminium form stable oxides and other compounds A lot of energy is needed to extract these this is often done through electrolysis Less reactive materials such as iron can be split with their bonds fairly easily through reduction reactions using carbon Unreactive metals like gold are extracted through various chemical reactions
49
What is rust a form of
Corrosion
50
What is rust
Hydrated iron (111) oxide
51
How to test that rust can not form with either water or air not present
For air but no water use calcium chloride so it reacts with any water in the test tube For water but no air use boiled water with a layer of oil above it to stop air getting to it
52
What speeds up the formation of rust
Salt dissolved in water and acid
53
Why does aluminium not corrode
It is protected by a natural layer of aluminium oxide which stops the layer of pure aluminium coming into contact with air Oxidisation on iron flakes off whereas oxidisation on aluminium does not
54
``` Use of metals: Aluminium Copper Gold Steal ```
Aluminium is low density and does not corrode so is suitable for bodies of planes Copper is a good conducted of electricity and does not react with water so it is good for electrical wires and water pipes Gold is a very good conducted and very unreactive so it is good for jewellery and electrical connections on circuit boards Steel is cheap and strong so is suitable as a building material
55
How do alloys make a metal stronger
Alloys contain atoms of different sizes Which distort the regular arrangement of atoms. This makes it harder for the layers to slide over each other so the metal is harder
56
What is brass and how is it used
It is an alloy of 70 percent copper and 30 percent zinc
57
What is 18 carat gold
75 percent gold and 25 percent copper | And other metals
58
What is duralumin
96 percent aluminium and 4 percent copper and other metals used in aircraft manufacture
59
Smart alloys
Smart alloys return to their original shape after being bent they are useful for spectacle frames and dental braces
60
What is an example of a smart alloy
Notinol returns to its original shape after being squealed by warming it Notional tubes are used to open up arteries and as spectacle frames
61
What is nitinol made of
Nickel and titanium
62
What is an ore
A naturally occurring rock that contains metal or metal compounds at a sufficient amount to make it worthy to extract them
63
What is crude oil
A mixture of compounds called hydrocarbons
64
What is an alkane
A hydrocarbon with the formula CnH2n plus 2 So an alkanes hydrogen is always double the amount of the carbon plus 2
65
What is meant by saturated hydrocarbon
The hydrogen is bonded to the carbon with double bonds making it relatively unreactive except for with oxigen Alkanes are saturated
66
What are small hydrocarbons states
Gases
67
What are hydrocarbons with five to 12 carbons states
Liquids
68
Large hydrocarbons with many carbons are at which state
Solid
69
What is the sequence in events in distillation
Heating Evaporating Cooling Condensing
70
What is complete combustion
The hydrogen in hydrocarbons oxidises to form water and the carbon oxidises to form carbon dioxide Hydrocarbon+ oxygen=>water and carbon dioxide
71
What is incomplete combustion
Carbon monoxide produced, particles of carbon (seen as soot or smoke)
72
What happens to sulphur compounds in hydrocarbons when they are burnt
Soulful dioxide
73
What are the five gases that can be released into the air by the combustion of fuels
``` Water vapour Carbon dioxide Carbon monoxide Particles ( carbon) Sulphur dioxide ```
74
8 factors that have to be considered when deciding weather or not to use a fuel/ how to use a fuel
``` The energy value of the fuel in joules The availability of the fuel How the fuel can be stored The cost of the fuel The toxicity of the fuel Any pollution that the fuel may cause such as sulcus dioxide How easy it is to use the fuel ```
75
Positives of solid fuels (coal) | And negatives
Easier to store | Harder to light
76
Benefits of liquid and had fuels
Light easily | Flow through pipes
77
Problems with soulful dioxide
Causes acid rain when soulful dioxide dissolves in clouds
78
Effects of acid rain
Reacts with metals and rocks such as limestone buildings and statues are damaged as a result Acid rain damages the waxy layer on leaves of trees and make it harder for plants to soak up the minerals they need for growth Acid rain makes lakes and rivers too acidic for some aquatic life to survive
79
How is sulphur dioxide dealt with
It can be removed from waste gases after the combustion of the fuel by treating it with calcium carbonate to form calcium sulphate this can be used to make plaster board
80
What does a greenhouse gas do
Absorb thermal energy and prevent it from going back into space
81
The four steps of the greenhouse effect
The suns rays enter the earths atmosphere Heat is reflected back off of the earths surface Heat is absorbed by greenhouse gases such as co2 or methane The earth gets hotter
82
Effect of global warming two things
Global weather patterns will change drought and flooding Polar ice caps will melt raising sea levels increased coastal erosion and flooding of low lying land including land where major cities lay
83
How are scientists trying to control the amount of co2 in the atmosphere
Iron seeding of oceans Converting carbon dioxide into hydrocarbons
84
Advantages of biofuels
Carbon neutral
85
Negatives about biofuels
Ethical issue that people think that it is bad to make fuel out of food crops
86
Problems with hydrogen fuel
Need electricity to produce which uses hydrocarbons to make Not convenient, very flammable May explode must be compressed and chilled then stored in tough insulated tanks
87
What is the name for 1 2 3 and 4 carbons in a hydrocarbon
Meth Eth Prop But
88
How is cracking done
Fractions containing large hydrocarbons are vaporised then passed over a hot catalyst to break them into smaller pieces
89
Why do we crack hydrocarbons
Large molecules aren't efficient They don't flow easily Crude oil often contains too many large hydrocarbons and too little small to meat demand
90
What is an Alkene
An unsaturated hydrocarbon this happens by the carbon atoms having double bonds The formula for alkanes is to double the amount of carbons to get the hydrogens
91
Testing for alkenes
Bromine water is used | An Alkene will turn brown bromine water couler less as it reacts with the double bond
92
Use for alkenes
Polimers
93
What are Polimers
Very large molecules made when many smaller molecules join end to end the smaller molecules are called mine mets
94
Ethan can polomerise to form
Polyethene
95
Propane can polomerise to form
Poly proper
96
Use for poly ethane Polypropene Polychloerothene
Polyethene plastic bags and bottles Polypropene crate and ropes Polychlorothene water pipes and insulation
97
Uses of polymers
Ethane flexible cheap insulator plastic bags and bottles coating on wires Proper flexible and strong buckets and crates PVC tough cheap and long lasting window frames Tetrafluoroethene tough and non stick Coating on pans
98
Polymer problems
Are not biodegradable although chemicals can be added to make the degrade When incinerated toxic gases are produced unless burning at very high temp
99
Problems with recycling
Difficult to seperate different plastics

Chem (9 decks)

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