Managing Resources Flashcards

Question

What is enthalpy if the reaction is endothermic?

Answer 1

Positive (products higher than reactants)

Answer 2

negative (reactants higher than products)

Answer 3

Exothermic is easier as there is less activation energy.

Answer 4

The measurement of heat energy changes during a chemical reaction or change of state.

Answer 5

An insulated reaction vessel designed to measure energy changes (heat loss or gain) with no (or minimal) heath loss to the surroundings.

Answer 6

An insulated reaction vessel designed to measure enthalpy for combustions of solid and liquid fuels.

Answer 7

Bomb calorimetry is a highly accurate techniques when compared to known molar enthalpy of combustion values.

Answer 8

The bomb is pressurised with oxygen gas and the weighed pellet of fuel is combusted via an ignition fuel.

Answer 9

It disperses heat within the water, ensuring even temperature.

Answer 10

Incomplete combustion - resulting in less energy released. Heat released from combustion is being absorbed by other mediums (metal or air or oxygen inside) Release of heat from combustion is not instantaneous - some heat may be absorbed by the water, which is further lost by the air. Depending on the fuel, mass may change overtime (evaporation)

Answer 11

Q = m x c x ^T (joules)

Answer 12

^H = m x c x ^t/1000 x n (kJ/mol)

Answer 13

Fuels with higher molar enthalpy of combustion energy can be considered a better fuel source.

Answer 14

^H/MW (kJ/g)

Answer 15

^H/MW x density (kJ/L)

Answer 16

More fuel would be required to reach a higher energy output. This would increase the amount and cost of resources required to produce the fuel source.

Answer 17

They are important processes in the cycling of carbon and oxygen on Earth.

Answer 18

Photosynthesis is a process carried out by plants and micro-organisms such as plankton, algae and cyanobacteria. It converts carbon dioxide, water and light energy (in the form of sun) into glucose (a form of chemical energy) and oxygen. 6CO2(g) + 6H2O(l) -> (energy) C6H12O2(g) + 6O2(g) ^H = -2802kJ/mol. This is an endothermic process (positive enthalpy), in which the absorption of energy (sunlight) is done by chlorophyll.

Answer 19

It reduces the CO and CO2, reducing the greenhouse effect.

Answer 20

Destroying trees means there are less places to store CO2 which means we are burning it more and storing it in our atmosphere.

Answer 21

It is a reaction carried out by all living things to release chemical energy stored in the covalent bonds of carbohydrates and lipids. C6H12O6(s) + 6O2(g) -> 6CO2(g) +6H2O(l) ^H = -2802kJ/mol This reaction is releasing energy (exothermic reactions). Occurs within the mitochondria.

Answer 22

Through burning of coal and natural gas.

Answer 23

The combustion process (exothermic) releases energy to heat the water producing steam The movement of steam drives a turbine which in turn generates electricity using electromagnetic proprieties. The faster the turbine spins the more energy produced. This is an exothermic reaction.

Answer 24

It is fuelled using fossil fuels producing CO2.

Answer 25

Photovoltaic Cells

Answer 26

Photovoltaic cells work to convert sunlight directly into electricity.

Answer 27

Produces no pollution when operating Low start up cost Renewable

Answer 28

During production of cells carbon emissions are produced They take up lots of land. Don't work during the night Prone to breaking due to weather

Answer 29

Cheap and readily fuels Renewable energy source

Answer 30

A redox reaction is a chemical process that involves the transfer of electrons.

Answer 31

The oxidation number for any free element is always 0 The oxidation number of monatomic ion equals the charge of the ion (including the sign) The usual oxidation number of hydrogen is +1 (in compounds containing elements that are less electronegative than hydrogen it is -1) The oxidation number of oxygen is -2 (exceptions do apply) The oxidation numbers of group 1, 2 and 7 elements are +1, +2 and -1 respectively (exceptions do apply) The sum of oxidation numbers of all elements within a neutral compound is 0 The sum of the oxidation numbers in a polyatomic ion (ions containing multiple elements) is equal to its charge

Answer 32

Is a species that is reduced but brings upon oxidation.

Answer 33

A species that in it self is oxidised but brings upon reduction.

Answer 34

A fuel cell is a device that converts the chemical energy of a fuel (hydrogen, natural gas, methanol) and some oxidant into electrical energy. Fuel cells are similar to batteries (galvanic cells that convert chemical energy into electrical energy). However, fuel cells do not run down or require charging. And will produces electricity as long as a source of fuel and a source of an oxidant are supplied.

Answer 35

Galvanic cells as they require a consistent flow of reagents to enable electricity generation.

Answer 36

If you consistently supply fuel, the cell with continuously provide power. This source could be infinite if enough fuel was supplied.

Answer 37

Hydrogen fuel cells use the chemical energy of hydrogen to cleanly produce electricity.

Answer 38

Expensive to manufacture due the high cost of catalysts. Hydrogen is expensive to produce and not widely available.

Answer 39

The oxidation occurs at the anode, the hydrogen gas is oxidised, producing electrons that move to the cathode generating an electrical current. The electrons generated at the anode, flow to the cathode where reduction occurs converting protons and oxygen to water. The flow of electrons allows for the generation of current.

Answer 40

Cleanly produces energy Produces water which is a green house gas but not a horrible one Has the highest energy density per gram

Answer 41

The Hydrogen gas is flammable It produces water which is a green house gas.

Answer 42

Anode: H2 -> 2H+ + 2e- Cathode: 1/2O2 + 2H+ +2e- -> H2O Overall: H2 + 1/2O2 -> H2O

Answer 43

Chemical energy to electrical energy

Answer 44

- A battery consists of two or more galvanic cells - the cells are connected in a series arrangement - they transform chemical energy into electrical energy - their primary function is to store and release electrical energy - the oxidation and reduction reactions create an electrical potential difference - drives the flow of electrons from anode to cathode - there are two types primary and secondary cells

Answer 45

- Non -rechargeable - Designed to be used only once - The reactions occurring at the anode and cathode are non-reversible - Once the anode has been consumed, the cell stops producing a potential difference, therefore it no longer produces a current.

Answer 46

Mercury, alkaline and zinc carbon

Answer 47

- They're are rechargeable - They transform chemical energy into electrical energy by a redox reaction that is reversable. - The reversibility of the anode/cathode reactions allow the cell to be recharged using direct current (DC) electricity. - Two types of reactions occur, discharging and recharging.

Answer 48

Nickel-cadmium and lead-acid.

Answer 49

Low cost High reliability

Answer 50

They need replacing, they run down, they pollute and they don't have a long life

Answer 51

Low cost High reliability low maintenance long run time low pollution long life

Answer 52

They are rechargeable fuel cells that can be used to store power (wind and solar) They can be charged (electrical energy to chemical energy) and discharged (chemical energy to electrical energy) via reversible redox reactions. (secondary batteries)

Answer 53

Two electrolyte solutions are separated by a proton exchange membrane which only allows for the flow of electrons and protons, preventing the solutions from mixing. Increasing the size of the membrane will increase the rate of charging and discharging

Answer 54

Cathode: Zn2+ + 2e- -> Zn (reduction) Anode: Ce3+ -> Ce4+ + e- (oxidation)

Answer 55

Anode: Zn -> Zn2+ + 2e- (oxidation) Cathode: Ce4+ + e- -> Ce3+ (reduction)

Answer 56

- Unlimited capacity - electrolytes are stored externally therefore wide potential for use. - Cells are rechargeable - meaning that the electrolytes can be used indefinitely - Can be discharged for extended period and recharged indefinitely without loss of output - No emissions contributed to the atmosphere during operations - Components of a cell can be laid out in carrying configurations - can be buried and stored within tanks underground - the bigger the tank the more energy meaning

Answer 57

The membrane can decay this is the expensive part.

Answer 58

Steam methane Reforming (SMR) Biomass Gasification Electrolysis of seawater (clean)

Answer 59

It is a process that heats methane obtained from natural gas (from fossil fuels) in the presence of steam and a catalyst. CH4(g) + H2O(g) <-> CO(g) +3H2(g) Therefore this is not a clean method to produce hydrogen gas.

Answer 60

- Large scale production - Existing infrastructure and processes is used for the production of most hydrogen world-wide

Answer 61

- Produces carbon monoxide - Uses non-renewable natural gas - Requires constant heating supplied by fossil fuel combustion - Uses fossil fuels

Answer 62

It is a controlled process that uses heat, steam and oxygen to convert biomass to hydrogen and other products. The steam reacts with carbon organic compounds to produce carbon monoxide and hydrogen. C(s) + H2O(g) -> CO(g) +H2(g) Not a clean source as it produces carbon monoxide.

Answer 63

Lowers green house emissions as the biomass removes carbon dioxide from the atmosphere during growth Cleans up our rubbish as the soot is a result of dead matter

Answer 64

Produces carbon monoxide

Answer 65

Seawater has the potential to produce hydrogen gas from an essentially inexhaustible supply. Electrolysis of seawater requires an energy input that is much higher than the energy output from hydrogen. An electrical current is applied at the cathode, resulting in the reduction of water. H2O(l) + 2e- -> H2(g) +2OH-(aq) This cleanly produces Hydrogen gas.

Answer 66

If the energy needed for the reaction is produced through fossil fuels, this process is both environmentally and financially costly. The energy is coming from fossil fuels.

Answer 67

If the energy needed is produced through a renewable source (solar or wind), this process produces green hydrogen and is considered a renewable source.

Answer 68

The treatment of water depends on its raw source: depending on location impurities and it depending on its intended use will change the level of purification.

Answer 69

1. Coagulation 2. Flocculation 3. Sedimentation 4. Filtration 5. Disinfection 6. Fluoridation

Answer 70

It is the settling of the floc aggregates.

Answer 71

it is the removal of solid impurities, it is done through passing dirty water through layers of sand and charcoal.

Answer 72

It is the removal of any biological contaminants.

Answer 73

It is the controlled adjustment of fluoride content within water.

Answer 74

It is the chemical process of neutralising the surface charge of particles.

Answer 75

It is the physical process of clustering (aggregation) of impurity particles.

Answer 76

Due to the presence of weathering of rocks, suspended inorganic (non-carbon containing) solids are found within water. These include clays - aluminosilicate minerals composed of aluminium silicon and oxygen. Clay particles have particle sizes in the micrometre range, making them difficult to remove.

Answer 77

Dirt, ions, heavy metals, high concentration of fertilisers and rocks.

Answer 78

True solution less than 10^-7 Colloidal solution between 10^-7 and 10^-5 Suspensions particles 10^-5

Answer 79

A true solution (a substance that is homogenously dispersed within another substance, i.e water) has a particle size in the nanometre to micrometre range. Within the water, clay particles form a colloidal suspension due to particle sizes in the micrometre range. Anything with particle size greater than 10^-5cm, is considered a suspension. Increasing the particle size of the impurities will cause them to drop to the bottom because of gravity, these can then be poured out.

Answer 80

The high content of sodium chloride within sea water, is undrinkable. The amount of sale within sea water is much higher than what can be processed by the human body.

Answer 81

Reverse osmosis is used to remove a solute. Pressure is applied to the side with higher salt concentration. This overcomes the osmotic pressure (spontaneous movement of water due to osmosis). The water passes through the semi-permeable membrane but the solute (salt) remains trapped on the other side. The pressure applied to the salt water, the water moves from low to high concentration leaving the salt on one side, allowing for the fresh water to be retrieved.

Answer 82

- It is an easy process - Produces Potable water - Abundant amount of seawater can be used to lower the demand of fresh water supplied - This process is not effected by climate (drought)

Answer 83

- Not cheap due to the pressure which is dangerous so the specialised equipment needed is costly. - To maintain the pressure is also costly. - requires a large amount of energy - generation of brine as a waste product needs disposing - The heat generated can affect local ecosystems

Answer 84

Saline water is heated until boiling and the pure water vapour is condensed and collected.

Answer 85

The sea water is heated this produces steam, fractional distillation meaning salt does not go as well. The water vapour is then cooled resulting in condensation which drops as potable water which can be extracted.

Answer 86

Cyanobacteria can lead to algal infections Cholera to an estimated 143000 deaths yearly These are all waterborne infectious bacteria Thermal distillation would be the only process to remove this

Answer 87

Plants require nutrients for growth and to carry out normal cellular processes such as photosynthesis, respiration and reproduction.

Answer 88

Plants (assimilate) take up nutrients as water soluble ions present in the soil solution (water in the soil) via their root system. If it is not water soluble it cannot act as a plant nutrient as water is good at dissolving ions because they are charged, which results in dipoles allowing for the ions to be absorbed.

Answer 89

Nitrogen - required for synthesis of amino acids, proteins, enzymes, DNA, RNA and chlorophyll Phosphorous - required for the synthesis of DNA, RNA, phospholipids (the building blocks of the cell membrane), and ATP - cells energy currency Potassium - regulates water transport and opening and closing of the stoma (gas exchange pores)

Answer 90

Nitrate ion (NO3-) Ammonium ion (NH4+) Hydrogen Phosphate ion (HPO42-) Dihydrogen Phosphate ion (H2PH4-) Potassium ion (K+) Calcium ion (Ca2+) Magnesium ion (Mg2+) Sulfate ion (SO42-)

Answer 91

N2 must be fixed (converted into a more useful form) before it can be used by living things e.g. N2 must be converted into soluble ions before it can be assimilated (uptake/absorbed via roots) by plants. Nitrogen fixation can be achieved by either natural or synthetic processes.

Answer 92

Nitrogen gas, N2, makes up 78% of the atmosphere. It is a relatively stable and inert molecule due to the presence of a string triple covalent bond between the nitrogen atoms. To split the N2 bonds large amounts of energy is required, often provided through lightening and volcanoes. This then allows it to be absorbed into the dirt

Answer 93

Lightning, volcanos and forest fires provides sufficient energy (high temperatures) to break the strong N2 covalent triple bond, allowing it to react with atmospheric oxygen and form nitrogen oxides. N2 + O2 -> 2NO (nitric oxide) 2NO + O2 ->2NO2 (nitrogen dioxide) Nitrogen dioxide then dissolves in water vapour in the atmosphere forming nitrous acid (HNO2) and nitric acid (HNO3) 2NO2 + H2O -> HNO2 + HNO3

Answer 94

Both of the acids ionise producing soluble nitrate ions (NO3-) and nitrite ions (NO2-) which are deposited into the soil during rain fall. HNO3 + H2O → H3O+ + NO3- (full ionisation – strong acid) HNO2 + H2O ⇌ H3O+ + NO2- (partial ionisation – weak acid).

Answer 95

Nitrogen containing compounds can also enter the soil through the waste (excrement) from living animal and plants. - when deceased animals and plants start to decay (complex organic molecules e.g. polymers, DNA broken down by bacteria into simpler, smaller molecules and ions). - Aerobic decay (O2 present, breakdown products exist in their maximum oxidation state): N containing compound -> NO3- (nitrate ion). - Anaerobic decay (complete absence of O2, breakdown products exist in their minimum oxidation state): N containing compound -> NH3 (ammonia). This process increase nitrogen content within the soil.

Answer 96

Nitrifying bacteria in the soil oxidise ammonia (NH3) and ammonium ions (NH4+) into nitrite ions (NO2-) and nitrate ions (NO3-). NH3/NH4+ -> NO2- -> NO3-

Answer 97

Denitrifying bacteria in the soil reduces the nitrate ions (NO3-) to nitrogen gas under anaerobic conditions. NO3- -> N2

Answer 98

The synthetic Haber process converts atmospheric nitrogen (N2) to ammonia (NH3) under high pressure and temperature. N2 + 3H2 -> 2NH3

Answer 99

In a natural ecosystem, the rate at which plants uptake nutrients from the soil, should be balanced by the rate at which nutrients are returned to the soil via the process of decay e.g leaves falling in autumn.

Answer 100

Human life is dependent on crop farming to produce food and fuel. This farming depletes the soil of nutrients as the plants are grown and harvested i.e. no decay to replenish the soil of nutrients. Therefore, the soil becomes infertile and require fertilizers to be added to grow more crops Fertilisers improve plant fertility by adding nutrients containing nitrogen, phosphorus and potassium (and other trace elements) into the soil.

Answer 101

Dry - Is dumping organic fertiliser and waiting for it to rain. Wet - is using aqueous fertiliser.

Answer 102

Natural fertilisers are broken down by decomposers (bacteria) in soil. These include manure, compost, blood and bone and wood ash.

Answer 103

Artificial fertilisers consist of nutrients within a water-soluble compounds and can be taken up by plants directly from fertilisers. Ammonium nitrate/sulfate, urea, calcium dihydrogen, phosphate, potassium chloride. Using artificial fertilisers means that they are not relying on there to be enough nutrients. Artificial is used more because it is easier to access.

Answer 104

The use of fertilisers can lead to eutrophication, especially after periods of heavy rainfall. Excess nitrogen and phosphorus from fertilisers, detergents (contain phosphate groups) or sewage can be leached from soils into waterways e.g. rivers and lakes causing eutrophication The increase in available nutrients promotes the excessive growth of aquatic plants including photosynthetic microbes including; algae and bacteria. These microbes form a bloom which prevents sunlight from reaching into the waterway. Aquatic plants underneath the bloom do not receive sunlight and are unable to photosynthesise causing them to die. Aerobic bacteria decompose the dead plant matter, further depleting the oxygen supply in the water and causing the death of aquatic organisms (plants, fish etc.). When the oxygen supply is fully depleted, anaerobic bacteria decompose the plant and animal remains generating products that are toxic to the water, making the water even less habitable for the remaining organisms.

Answer 105

How easily a metal undergoes oxidation. The higher in the series a metal is, the the more likely it will displace the metals lower in the series (undergo oxidation). This is the reverse for the ion of that metal, which does not want to undergo reduction.

Answer 106

It is below aluminium and above zinc.

Answer 107

To prevent the formation of iron oxide (rust) on ships a zinc bar is used. Zinc appears higher than iron in the metal reactivity series, will be oxidised first. Once consumed, zinc bars can be easily replaced to further protect iron components within ships. This same concept is used within the process of galvanization.

Answer 108

Most metals are sufficiently reactive to be found within the Earth's crust as minerals, a compound containing the metals and other elements (commonly oxygen and sulfur) Some unreactive metals (Ag, Au, Pt) are found naturally in an uncombined state. A deposit within the Earth's crust where the concentration of a mineral is higher than usual is referred to as metal ore. Ores contain other minerals other than the metal mineral of interest (referred to as gangue). When metals are mined (extracted from the crust) only metal ores with a high percentage of the metal/mineral of interest are economically viable to extract. If found naturally they're more likely to undergo reduction.

Answer 109

Producing pure metals from their ores is a multi-step process that may involve 1. Extraction 2. Concentration 3. Conversion 4. Reduction 5. Refining

Answer 110

The removal of metal ore from the Earth's crust.

Answer 111

- The ore is crushed and ground. - Completed at mine site to reduce cost of transportation and rock disposal. - Removal of gangue to form mineral concentrate. - May not be required if mineral in ore was in high concentration or it is possible to remove mineral in presence of waste.

Answer 112

It converts mineral to a compound that can be reduced, therefore is not required if compound can already be reduced. E.g chemical process like roasting the sulfide mineral to produce the metal oxide or sintering. The mineral is then leached with an acid to produce a sulfate, this solution is then filtered to remove any suspended solids. The powdered mineral is then added to precipitate any less reactive metal ions.

Answer 113

Depends on the reactivity of the metals but may include; molten electrolysis, aqueous electrolysis and chemical reduction via a chemical reducing agent.

Answer 114

- Remaining impurities can be removed by electrolysis or further chemical reactions if necessary. - Removing trace impurities (not required for Al or Zn).

Answer 115

- Blast furnaces used are held at temperatures of 1000 degree Celsius. - High temperatures are created and maintained by fossil fuels. - Produces large amounts of carbon dioxide.

Answer 116

- High temperatures are not required. - Energy and cost saving compared with chemical reduction or a molten cell. This is currently used for 90% of the worlds zinc production. Molten electrolysis is expensive.

Answer 117

1. low energy steps of crushing, grinding, leaching and floatation. 2. medium energy steps of roasting and heating 3. high energy steps of reduction (blast furnace and electrolysis)(8-12kJ per tonne metal) 4. highest energy steps electrolysis of molten electrolyte e.g Al (30-50kJ per tonne metal)

Answer 118

Recycling metals is becoming increasingly important to conserve finite resources. - Over 50% of aluminium and lead are produced from recycled materials. Recycling resources means they become finite slower as they do degrade but they can be used a few more times prior.

Answer 119

- Conserves finite resources: both metals and fossil fuels are used in the production of metals. - Reduces energy requirement: lower energy cost to recycle than produce from ores (roasting in furnace and undergoing reduction via electrolysis not required) - Reduces mining: mining is damaging the environment, creates waste materials e.g. gangue and is expensive - Reduces landfill: sulfur oxides (acid rain), nitrogen oxides (photochemical smog), soot (C), carbon monoxide (toxic gas) and greenhouse gases are all generated in the production of metal. - Reduces water materials: waste is harmful to the environment. - Reduced landfill: Recycling reduces the amount of waste products sent to landfill. If metals are recycled the demand of finite resources are elevated.

Answer 120

Polymer (plastics) production has created an abundance of waste products. - Polymers must be sorted before recycling based on both chemical and physical properties.

Answer 121

Physical (broken down by shredding or melting) Chemical (broken down to be reused to make new polymers or used as fuels).

Answer 122

Conserves fossil fuels: most polymers are created from petroleum a finite fossil fuel feedstock. Minimises energy requirement: lower energy cost to recycling than synthesise from scratch. It reduces landfill: recycling reduces the amount of waste products sent to landfill.

Answer 123

They contain dispersion forces or hydrogen bonding between the polymer chains. These soften when heated, harden and become more rigid when cooled. They can be recycled by heating and reshaping. They can be recycled many times until polymer chains decompose.

Answer 124

They contain a high degree of cross-linking (covalent bonds). They do not soften or change in shape when heated. They will char or burn if heated sufficiently as the covalent bonds break and the polymer decomposes. Therefore they cannot be recycling.

Answer 125

They are formed by combining two or more materials that have quite different properties. The different materials work together to give the composite unique properties, but within the composite you can easily tell the difference between the materials and they do not blend or dissolve into each other. These are very strong materials and separating them is difficult.

Answer 126

The composite material consists of two materials, a matrix and a reinforcement. The matrix is the bulky material and the reinforcement is the material embedded throughout the matrix.

Answer 127

Wood, mud bricks and concrete

Answer 128

Improved properties both materials can be utilised in comparison to their original materials. Designed for specific use

Answer 129

Composite materials are harder to recycle than single component materials due to the mixing and incorporation of different components of the resulting material. Most composite materials use thermosetting polymers as the matrix, therefore, they cannot be heated to separate the matrix from the reinforcement. They can also be recycled using pyrolysis. This heats the composite material under oxygen to combust the thermoset polymers and retain the reinforcement fibres. This is limited due to high costs, low quality of separated components and lack of incentives and infrastructure.

Answer 130

- Science is a global enterprise that relies on clear communication, international conventions, and review and verification of results. - International collaboration is often required in scientific investigation.

Answer 131

- Development of complex scientific models and/or theories often requires a wide range of evidence from many sources and across disciplines. - New technologies improve the efficiency of scientific procedures and data collection and analysis. This can reveal new evidence that may modify or replace models, theories, and processes.

Answer 132

- Advances in scientific understanding in one field can influence and be influenced by other areas of science, technology, engineering, and mathematics. - The acceptance and use of scientific knowledge can be influenced by social, economic, cultural, and ethical considerations.

Answer 133

- Scientific knowledge, understanding, and inquiry can enable scientists to develop solutions, make discoveries, design action for sustainability, evaluate economic, social, cultural, and environmental impacts, offer valid explanations, and make reliable predictions. - The use of scientific knowledge may have beneficial or unexpected consequences; this requires monitoring, assessment, and evaluation of risk and provides opportunities for innovation. - Science informs public debate and is in turn influenced by public debate; at times, there may be complex, unanticipated variables or insufficient data that may limit possible conclusions.

Answer 134

Hydrogen has the highest energy density per gram and combustion yields old water H2(g) + 1/2 O2(g) -> H2O(l) ^H=-286kJ/mol This process does not produce carbon dioxide reducing contributions to the green house effect. Can also be used as a fuel source for vehicles - further reducing emissions from the transport sector. Also, hydrogen can also act as a reductant, reducing iron oxide to iron. Removing the need for coal-based iron production. further reducing coal demand.

Answer 135

Hydrogen is incredibly flammable, so storage is an issue. We lack the infrastructure to support the manufacture and distribution of hydrogen based electricity.

Answer 136

Coagulation is done by neutralising the surface charge by adding salts of highly charged cations (Al3+) and/or charged polymers to the solution which are attracted to the negatively charged clay particles, neutrilising the negative charge. This occurs as like charges repel. The suspension becomes destabilised and dispersions forces allow particles to aggregate, joining them together in layers to create large sized particles of clay called microflocs. These microflocs, are not soluble in water and eventually settle at the bottom. Allowing for it to be agitated, forming a floc, due to its larger particle size and mass it settles at the bottom of the container to be removed as sediment.

Answer 137

A feedstock is a raw material used to provide reactants for an industrial reaction.

Answer 138

The same as electrolytic cells, pushing a reaction in a non spontaneous reaction. Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. Reduces the ion to its pure metal.

Answer 139

Nitrogen fixing bacteria Decay of dead animals Natural nitrogen fixation which needs high energy (acid rain equations and similar process).

Answer 140

A process of conversion, which uses oxygen and high energy.

Answer 141

Uses an acid to leach out the metal which is then produces zinc sulphate.

Answer 142

Normal carbon amount, normal hydrogen plus an oxygen eg C2H5OH

Answer 143

It is the process of reacting, triglycerides with an alcohol to produce esters and glycerol. in the presence of a catalyst

Answer 144

The replacement of the alkyl group of an ester by another through interaction of the ester and alcohol

Answer 145

It causes the water to bubble and froth up causing the mineral to separate and removed.

Answer 146

It is an ion that contains a charged (anionic) region and a non-polar region e.g hydrocarbon chain. This forms a thin hydrophobic layer over the surface of minerals, increasing their floatability.

Answer 147

1. The powdered mineral and gangue are mixed with water to form a slurry. 2. Frothing agents and collectors are added. 3. Air is blown through the slurry and it is stirred to create bubbles which the minerals attach to and float to the surface. 4. Froth containing the mineral is skimmed off and excess water is removed. 5. Waste gangue sink to the bottom.

Answer 148

The anionic region adsorbs to the surface of the mineral powder through ionic interaction. The nonpolar region attaches to the air bubble which rise to the surface of the slurry and carry the mineral up because it is hydrophobic.

Answer 149

The mineral must be converted into a soluble molecule in order for it to undergo reduction via electrolysis.

Answer 150

- everything above water (Al and above) is done by molten electrolysis as water would be reduced preferentially to the metal ions - Zinc is chemical reduction ot electrolysis of an aqueous salt - Between iron and lead is chemical reduction - Copper and Hg is roasting - gold and silver are found uncombine.

Answer 151

Carbon materials are finite, so if it is used in feedstock, less is available to use to generate plastics and produce metal. This will increase the green house gases with the atmosphere.

Answer 152

In a water treatment plant, flocculation is an important step in the purification process because it helps remove suspended particles and impurities from water. During flocculation, positively charged polymers are added to the solution and attract the negatively charged clay particles. Dispersion forces allow particles to aggregate and form larger clumps, called flocs, which can be easily removed by settling or filtration.

Answer 153

2. Nitrification converts ammonia, found in animal waste and ammonia and ammonium found in fertilizers into the high soluble nitrate ion, which plants can uptake through their roots. Nitrates are essential nutrients for plant growth and enhance crop productivity. However, if these processes are disrupted, it can lead to environmental issues. For example, excessive use of nitrogen fertilizers without proper management can result in increased nitrate runoff into water bodies. This can lead to eutrophication, where excessive nutrient levels cause algal blooms, depleting oxygen levels in water and negatively impacting aquatic life.

Answer 154

Photovoltaic cells have several advantages compared to steam turbines as sources of electricity generation. Photovoltaic cells directly convert sunlight into electricity, making them a renewable and clean energy source. They have no moving parts, requiring low maintenance. Photovoltaic cells are modular and scalable, suitable for installations of various sizes. They operate silently, making them suitable for urban environments. However, there are also disadvantages to consider. Photovoltaic cells have intermittent energy production due to their dependence on sunlight, making energy storage necessary for continuous power supply. The initial installation costs can be high, although prices have been decreasing. The efficiency of photovoltaic cells is influenced by factors such as weather conditions and panel orientation.

Answer 155

Bioethanol is produced through a process called fermentation. In this process, carbohydrates such as glucose, are converted into ethanol and carbon dioxide with yeast as the catalyst, as shown below. C6H12O6 (aq) → 2C2H5OH(l) + 2CO2 (g) ΔH = -ve kJ/mol Fractional distillation is used to increased the concentration of the ethanol produced.

Answer 156

Incomplete combustion is more likely to occur with longer-chain carbon-based fuels compared to shorter chains. As the length of carbon chains increases, the ratio of carbon to oxygen increases, limiting the availability of oxygen to form carbon dioxide. Larger molecules also have stronger dispersion forces making them less volatile fuel sources (more energy required to break interactions). This reduces the ability to mix effectively with gaseous oxygen during combustion. As a result, only partial oxidation of the fuel occurs, leading to the formation of carbon monoxide (CO) and soot (particulate matter). Incomplete combustion of longer-chain fuels can release higher levels of pollutants, including carbon monoxide, which is toxic and can impair oxygen transport in the bloodstream.

Managing Resources Flashcards

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