Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > Topic 10 - Using Resources > Flashcards

Topic 10 - Using Resources Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What are some examples of what humans use resources for

A

Use energy for heating, building materials, food or travelling

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

What are natural resources and give an example

A

-Things that form without human input, including anything coming from earth, sea or air
-E.g. cotton for clothing or oil for fuel

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

How are natural products replaced by synthetic products and give some examples of them

A

-Replaced by synthetic products or improved upon by man-made processes
-E.g. rubber is natural and extracted from the sap of a tree but man-made polymers have been made which can replace rubber in uses such as tyres

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

Give an example of where agriculture provides conditions where natural resources can be enhanced

A

The development of fertilisers have meant we can produce a high yield of crops

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

What is a renewable resource

A

A resource that reform at a similar rate to or faster than we use them

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

Give examples of renewable resources

A

-Timber is a renewable resource as trees can be planted following a harvest and only take a few years to grow
-Also fresh water and some food

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

What are non-renewable resources

A

Resources that aren’t formed quickly enough to be considered replaceable

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

Give examples of finite/non-renewable resources

A

-Fossil fuels and nuclear fuels such as uranium and plutonium
-Minerals and metals found in ores in the earth

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

What happens to finite resources after being extracted and give an example

A

-They undergo man-made processes to provide fuels and materials necessary for modern life
-fractional distillation is used to produce useable products such as petrol from crude oil and metal ores are reduced to produce a pure metal.

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

How to tell the difference between renewable and non-renewable resources in a table

A

-Renewable resources take longer to form
-They are also far less energetic

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

Give advantages of extracting finite resources and give an example

A

-May bring money into an area
-Creates jobs for people extracting
-E.g. Metal ore mines

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

Give disadvantages of extracting finite resources and an examples

A

-Bad for the environment as it uses a lot of energy, scare landscape and produces lots of waste and destroys habitats
-E.g. metal ore mine

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

What is sustainable development

A

An approach to development that takes account of the needs of present society whilst not damaging the lives of future generations

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

Why is extracting resources unsustainable

A

The amount of energy used and waste produced

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

How is processing resources into useful material unsustainable and give examples

A

Things such as glass or bricks can be unsustainable as the processes often use energy made from finite resources

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

How should we reduce the use of finite resources and why

A

People need to use less resources as it reduces the use of the resource but also anything needed to produce it

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

What can chemists do rather than stop using finite resources all together

A

-Develop and adapt processes that use lower amounts of finite resources and reduce damage to the environment.
-E.g. Catalysts that reduce the amount of energy required for certain industrial processes

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

How can scientists improve copper’s sustainability

A

Extracting is from low grade ore (ores without much copper in)

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

Outline bioleaching

A

-Bacteria are used to convert copper compounds in the ore into soluble copper compounds. separating out the copper from the ore in the process. The leachate (solution produced by the process) contains copper ions which can be extracted (e.g. by electrolysis or displacement with a more reactive metal like scrap iron).

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

Outline phytomining

A

Growing plants in soil that contains copper. The plants cant use or get rid of the copper so it gradually builds up in the leaves. The plant is then harvested, dried and burnt in a furnace and the ash contains soluble copper compounds from which copper can be extracted by electrolysis or displaced using scrap iron.

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

What is an advantage of methods used to extract copper from low grade copper ores

A

They have a much smaller impact on damaging the environment

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

What is a disadvantage of methods used to extract copper from low grade copper ores

A

They’re slow compared to the traditional methods

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

Give advantages of recycling metal

A

Uses much less energy than is needed to mine and extract new metal, it conserves the finite amount of each metal in the earth and cuts down on the amount of waste getting sent to landfill

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

How are metals usually recycled

A

By melting them and casting them into the shape of a new product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What happens to metals after being recycled

A

-Some have to be seperated
-However some don’t such as waste steel and iron can be kept together as they can both be added to iron in a blast furnace to reduce the amount of iron ore required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How does glass recycling help sustainability

A

By reducing the amount of energy needed to make new glass products, and also the amount of waste created when used glass is thrown away

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How is glass recycled

A

-Glass bottles can often be reused without reshaping
-Other forms of glass can’t be reused so they’re recycled instead and usually glass is separated by colour and chemical composition before being recycled
-The glass is crushed and then melted to be reshaped for use in glass products such as bottles of jars and it might also be used for a different purpose such as insulating glass wool for wall insulation in homes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is potable water

A

Water that is safe for human consumption and daily use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the difference between pure water and potable water

A

-Pure water is made up of only H2O molecules
-Potable water may contain different substances usually dissolves minerals and salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What characteristics do potable water have

A

-pH between 6.5 and 8.5
-The dissolved substances will be present in very small regulated quantities
-Free of bacteria and other harmful mcirobes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is desalination and where is it used

A

-Taking salt out of water
-In LICs or places with less salt water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the two methods for desalination

A

-Reverse osmosis
-Distillation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is distillation

A

Heat a mixture of salt and water so the water component evaporates and a precipitate is left behind and the vapour is then condensed in a cold condensing tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Difference between evaporation and boiling

A

-Boiling is at a specific point
-Evaporation is over a range of temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Why does domestic and agricultural sewage need to be processed

A

-To remove organic matter, harmful microbes, particulates and toxins
-If this didn’t take place it could potentially pose health risks for the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the first stage of the life cycle assessments

A

Getting raw materials - Extracting raw materials needed for a production can damage the local environment (e.g. mining metals as extraction can result in pollution due to the amount of energy needed
-Raw materials often need to be processed to extract the desired materials and this often needs large amounts of energy. E.g. extracting metals from ores or fractional distillation of crude oil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Outline the second stage of Life Cycle Assessments

A

-Manufacturing and Packaging - This can use a lot of energy resources and cause pollution (e.g. harmful fumes like carbon monoxide or hydrogen chloride)
-Also there are waste products produced by chemical reactions used to make compounds from their raw materials , however some waste can be turned into useful chemicals lessening potential pollution on the environemtn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Outline the third stage of Life Cycle Assessments

A

-Using the Products - The use of a product can damage the environment like burning fuels which release greenhouse gases and other harmful substances. Fertilisers can leach into streams and rivers causing damage to ecosystems
-How long or how many uses of a product is a factor as products that need lots of energy to produce but are used for ages mean less waste in the long run

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Outline the fourth stage of Life Cycle Assessmenrs

A

-Product Disposal - Products are often disposed of in landfill sites. This takes up space and polluted land and water (e.g. if paint washes off a product and gets into rivers)
-Energy is used to transport waste to landfill, which causes pollutants to be released into the atmosphere
-Products might be incinerated which causes air pollution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Outline the first stage of a LCA of plastic bags

A

Raw materials- Crude oil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Outline the second stage of a LCA of plastic bags

A

-Compounds needed to make the plastic are extracted from crude oil by fractional distillation followed by cracking and then polymerisation. Waste is reduced as the other fractions of crude oil have other uses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Outline the third stage of a LCA of plastic bags

A

Using the product - Can be reused and used for other things as well as shopping like bin liners

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Outline the fourth stage of a LCA of plastic bags

A

Product disposal - Recyclable but not biodegradable and will take up space in landfill and produce land

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Outline the first stage of a LCA of a paper bag

A

Raw materials - Timber

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Outline the second stage of a LCA of a paper bag

A

Manufacturing and packaging - Pulped timber is processed using lots of energy. Lots of waste is made.

46
Q

Outline the third stage of a LCA of a paper bag

A

Using the product - Usually only used once

47
Q

Outline the fourth stage of a LCA of a paper bag

A

Product disposal - Biodegradable non-toxic and can be recycled

48
Q

What are the problems with LCAs

A

-The effect of some pollutants is harder to give a numerical value (e.g. it’s difficult to apply a value to the negative visual effects of plastic bags in the environment compared to paper ones)
-LCAs are not objective and may have bias as it takes into account the values of the person carrying out the assessment
-Selective LCAs which only show some impact of a product can also be biased as they can be written to deliberately support the claims of a company to give them positive advertising

49
Q

Where is fresh water found in the U.K.

A

From rainwater which can collect as surface water (Lakes, rivers, reservoirs) or as groundwater ( in rocks called aquifers that trap water underground)

50
Q

How does the location in the U.K. affect where fresh water is collected from

A

Surface water tends to dry up first so in warm areas like the south east most of the fresh water from groundwater

51
Q

How can you test water in a lab before distilling it (pH and sodium chloride)

A
  1. Test the pH of the water using a pH meter. If the pH is too high or too low, you can neutralise it. You can do this with a titration but use a pH meter to tell you when the solutions neutral, rather than an indicator, as this won’t contaminate the water.
  2. Also test the water for sodium chloride by doing a flame test of a small sample if the flame turns yellow there’s sodium, to test for chloride take another sample and add dilute nitric acid followed by a few drops of silver nitrate solution and if chloride ions are present a white precipitate will form
52
Q

How to distill water in a lab

A

-Pour the salty water into a distillation apparatus and heat the flask from below. The water will boil and form steam, leaving any dissolved salts in the flask and the steam will condense back to liquid water in the condenser and can be collected as it runs out
-Then retest the distilled water for sodium chloride to check that it has been removed also retest the pH of the water with a pH meter to check that it’s neutral

53
Q

How does using reverse osmosis for desalination work

A

The salty water is passed through a membrane that only allows water molecules to pass through. Ions and larger molecules are trapped by the membrane so separated from the water.

54
Q

What are the pros and cons of distillation/desalination

A

Advantage - Can be applied on a large scale and can kill bacteria/microbes
Disadvantage - A lot of energy is required to boil and condense the water. Hard to dispose of left over salty water in a sustainable and non harmful way.

55
Q

How is freshwater treated before it’s used

A

Filtration - a wire mesh screens out large twigs etc, and then gravel and sand beds filter out any other solid bits
Sterilisation - the water is sterilised to kill any harmful bacteria or microbes. This can be done by bubbling chlorine gas through it or by using ozone or UV light

56
Q

What can industrial waste water contain aswell as organic matter that needs to be treated

A

-Harmfuls chemical
-The water therefore has to undergo additional stages of treatment before it is safe to release it into the environment

57
Q

What happens to waste water before being treated (first stage)

A

The sewage is screened - removing any large bits of material as well as any grit

58
Q

What happens in the second stage of waste water treatment

A

It is allowed to stand in a settlement and undergoes sedimentation - the heavier suspended solids sink to the bottom to produce sludge while the lighter effluent floats on the top.

59
Q

What happens in the third stage of waste water treatment

A

The effluent is removed from the settlement tank and treated by biological aerobic digestion. This is when air is pumped through the water to encourage aerobic bacteria to break down any organic matter - including other microbes in the water

60
Q

What happens in the fourth stage of waste water treatment

A

The sludge from the bottom of the settlement tank is also removed and transferred into large tanks. Here it gets broken down by bacteria in a process called anaerobic digestion

61
Q

What happens in the fifth stage of waste water treatment

A

The anaerobic digestion breaks down the organic matter in the sludge, releasing methane gas in the process. The methane gas can be used as an energy source and the remaining digested waste can be used as a fertiliser

62
Q

What happens in the sixth stage of waste water treatment

A

For waste water containing toxic substances, additional stages of treatment may involve adding chemicals (e.g. to precipitate metals) UV radiation or using membranes

63
Q

Give the advantages and disadvantages of waste water treatment

A

-Advantages - Solids left over can be used as fertiliser. No products wasted.
-Disadvantages- costs a lot to treat the waste water, and it takes a long time.

64
Q

Where is waste water treatment used as an alternative from desalination and treating potable water

A

In Singapore they are treating waste water and recycling it back into drinking supplied

65
Q

What are ceramics

A

Non-metal solids with high melting points that aren’t made from carbon-based compounds

66
Q

Outline clay ceramics

A

-Clay is soft material when it’s dug up, so can be moulded into different shapes
-When it’s fired at high temperatures, it hardens to form a clay ceramic
-It’s ability to be moulded when wet and then hardened makes clay ideal for making pottery and bricks

67
Q

Outline glass as ceramics

A

-Glass is generally transparent, can be moulded when hot and can be brittle when thin
-Most glass is soda-lime glass, which is made by heating a mixture of limestone, sand and sodium carbonate until melts. When the mixture cools it comes out as glass
-Borosilicate glass has a higher melting point than soda-lime glass. It’s made in the same way as soda-lime glass, using a mixture of sand and boron trioxide.

68
Q

What are composites

A

Composites are made of one material embedded in another. Fibres or fragments of a material are surrounded by matrix acting as a binder. The properties of a composite depend on the properties of the materials it made from.

69
Q

Outline fibreglass

A

-Consists of fibres of glass embedded in a matrix made of polymer. It has a low density but is very strong. It’s used for things like skis, boats and surfboards

70
Q

Outline carbon fibre as a composite

A

-Have a polymer matrix. The reinforce is either made from long chains of carbon atoms bonded together or from carbon nanotubes. These composites are very strong and light so are used in aerospace and sports car manufacturing

71
Q

Outline concrete as a composite

A

Is made from aggregate embedded in cement. It’s very strong making it ideal for use as a building material

72
Q

Outline wood as a composite

A

A natural composite of cellulose fibres held together by an organic polymer matrix

73
Q

How is low density poly(ethene) made

A

Made from ethene at a moderate temperature temperature under a high pressure. It’s flexible and is used for bags and bottles.

74
Q

How is high density poly(ethene)

A

Made from ethene at a lower temperature and pressure with a catalyst. It is used for water tanks and drainpipes as it is more rigid

75
Q

Outline thermosoftening polymers

A

-Contain individual polymer chains entwined together with weak forces between the chains. You can melt these plastics and remould them.

76
Q

Outline thermosetting polymers

A

Contain monomers that can form cross-links between the polymer chains, holding the chains together in a solid structure. Unlike thermosoftening polymers they don’t soften when heated. They’re strong, hard and rigid

77
Q

Outline ceramics properties

A

Include glass and clay ceramics like porcelain and bricks. They’re insulators of heat and electricity, brittle and stiff.

78
Q

Outline polymer properties

A

Insulators of heat and electricity, they can be flexible and are easily moulded. They have many applications including in clothing and insulators in electrical items.

79
Q

Outline composite properties

A

Depends on the matrix/binder and the reinforcement used to make them, so they have many different uses

80
Q

Outline metal properties

A

Malleable, good conductors of heat and electricity, ductile (can be drawn out into thin wire), shiny and stiff. Many uses including electrical wires, car body work and cutlery

81
Q

Outline iron alloys

A

Called steels which are made by adding small amounts of carbon or other metals to iron

82
Q

Outline bronze as an alloy

A

Copper + tin : is harder than copper. It used to make medals, decorative ornaments and statues

83
Q

Outline brass

A

Copper + zinc : Brass is more malleable than bronze and is used in situations where lower friction is required like in door fittings and water taps

84
Q

Outline gold alloys

A

-Used in jewellery : Pure gold is very soft. Metals such as zinc, copper and silver are used to harden the gold. Pure gold is described as 24 carat, so 18 carat means 18/24 of the alloy is pure gold

85
Q

Outline aluminium alloys

A

Used to make aircraft: has a low density but pure aluminium is too soft for making aeroplanes so it’s alloyed with small amounts of other metals to make to stronger

86
Q

What is corrosion

A

Where metals react with substances in their environment and are gradually destroyed

87
Q

Outline iron rusting

A

-Iron needs to be in contact with water and oxygen which are present in the air
-The equation is : iron + water + oxygen > hydrated iron(III) oxide
-Rust is a crumbly soft solid that soon flakes off leaving more iron available to rust so eventually all the iron in an object corrodes even if it wasn’t initially at the surface

88
Q

Outline aluminium corrosion

A

-Corrodes when exposed to air unlike iron objects they aren’t completely destroyed
-Aluminium oxide formed doesn’t flake away, it forms a nice protective layer that sticks firmly and stops further reaction place

89
Q

Outline the experiment showing oxygen and water are needed for iron to rust

A

-If you put an iron in a boiling tube with just water it won’t rust (water is boiled to remove oxygen and oil is used to stop air getting)
-If you put an iron nail in a tube with just air it won’t rust (calcium chloride can be used to absorb any water from the air)
-However if you put an iron nail in a boiling tube with air and water it will rust

90
Q

How can you prevent iron rusting with a barrier

A

-Painting/coating with plastic
-Electroplating (uses electrolysis to reduce metal ions onto an iron electrode to coat iron with a metal layer that won’t corrode)
-Oiling/greasing has to be used when moving parts are involved

91
Q

What is the sacrificial method for preventing iron rusting

A

-Inolves placing a more reactive metal like zinc or magnesium with the iron.
-Water and oxygen react with the sacrificial metal and not the iron

92
Q

How do some methods of preventing rust employ both a barrier and sacrificial method

A

An object can be galvanised with a coating of zinc spray that is firstly protective, but if it’s scratched it acts as a sacrificial metal

93
Q

What is the haber process

A

Used to make ammonia from hydrogen and nitrogen

94
Q

What is the equation for the haber process

A

N2 + 3H2 > 2NH3 (+heat)
<

95
Q

Why is the Haber process well suited for industrial scale

A

The reactants aren’t too difficult or expensive

96
Q

Outline the Haber process

A
  1. Nitrogen is obtained easily from the air (78% nitrogen)
  2. The hydrogen mainly comes from methane with steam to form H2 and CO2 3:1 (H:N)
  3. The reactant gases are passed over an iron catalyst. A high temperature (450°C) and a high pressure (200 atmospheres) are used
  4. Because the reaction is reversible some of the ammonia converts back into H2 and N2 again. It will reach dynamic equilibrium
  5. The 2NH3 is formed as a gas but as it cools in the condenser it liquifies and is removes. The unused H2 and N2 are recycled so nothing is wasted
  6. the 2NH3 produced can than be used to make ammonium nitrate - a very nitrogen rich fertiliser
97
Q

Outline why the temperature for the haber process is 450°C

A

-The forward reaction in the haber process is exothermic so increasing the temperature move the equilibrium the wrong way back towards the reactants H2 and N2 so the yield of ammonia would greater at lower temperature
-However the rate of reaction would be too slow at too low of a temperature
-Therefore it’s a comprise between yield and rate of reaction

98
Q

Outline why the pressure of the haber process is at 200 atmospheres

A

-Higher pressure moves the position of equilibrium towards the products since there are four molecules of gas of the left hand side for every two on the right so increasing pressure maximises the percentage yield and increases rate of reaction
-The pressure is set as high possible, without making the process to expensive to or dangerous to build maintain. Hence the 200 atmospheres operating pressure.

99
Q

Outline the use of an iron catalyst in the haber process

A

Makes the reaction go faster

100
Q

Why are formulated fertilisers better than manure

A

More widely available, easier to use, don’t smell and have enough of each nutrients so more crops can be produced

101
Q

What are the three main essential elements in fertilises and what happens if there aren’t enough of all

A

-Nitrogen, phosphorus and potassium
-If plants don’t get enough of these elements, their growth and life processes are affected. -These elements may be missing from the soil if they’ve been used up by a previous crop

102
Q

How do fertilisers help to increase the crop yield of something

A

-They replace missing elements or provide more allowing the craps can grow faster and bigger.
-They add nitrogen to plant proteins so the plant grows faster - increasing productivity

103
Q

What are NPK fertilisers

A

-Formulations containing salts of nitrogen, phosphorous and potassium in the right percentages of the elements

104
Q

Outline ammonia producing nitrogen contains compounds

A

-Ammonia can be reacted oxygen and water in a series of reactions to make nitric acid
-You can also react ammonia with acids, including nitric acid to get ammonium salt
-Ammonia and nitric acid react together to produce ammonium nitrate. This is a good compound to use in a fertiliser because it has nitrogen from two sources.

105
Q

What is the equation for ammonium nitrate

A

Ammonia + nitric acid > ammonium nitrate
NH3 + HNO3 > NH4NO3

106
Q

How is the reaction of ammonium nitrate carried out in industry

A

-The reaction is carried out in giant vats, at high concentrations resulting in a very exothermic reaction. The heat released is used to evaporate water from the mixture to make a very concentrated ammonium nitrate product

107
Q

How is the reaction of ammonium nitrate carried out in the lab

A

-The reaction is carried out on a much smaller scale by titration and crystallisation. The reactants are at a much lower concentration than in industry, so less heat is produced by the reaction and it’s safer for a person to carry it out. After the titration, the mixture then needs to be crystallised to give pure ammonium nitrate crystals. Crystallisation isn’t used in industry because it’s very slow.

108
Q

How can potassium be sourced for NPK fertilisers

A

potassium chloride and potassium sulphate can be mined

109
Q

What is the problem with mined phosphates for NPK fertilisers

A

-The phosphate salt in the rock are insoluble so plants can’t use them as nutrients

110
Q

How can soluble phosphates be produced for NPK fertilisers

A

-Reaction with nitric acid produces phosphoric acid and calcium nitrate
-Reaction with sulphuric acid produces calcium sulphate and calcium phosphate (single superphosphate)
-Reaction with phosphoric acid only produces calcium phosphate (triple superphosphate)

Chemistry (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions