Developing Fuels Flashcards

Question

How are alkanes named?

Answer 1

Name the **longest carbon chain** Identify + name any **alkyl side chains** in **alphabetical order** Use **di**, **tri**, **tetra** before the alkyl prefix is the side chains are **identical** Show the position of any side chains using the **lowest numbers possible**

Answer 2

A **mixture** of many hundreds of different hydrocarbons

Answer 3

Seperate the different hydrocarbons within crude oil

Answer 4

A representation of the atoms, bonds, and groups in a molecule

Answer 5

A representation of a molecule using lines to represent C-C bonds

Answer 6

**Meth**ane

Answer 7

Don't accurately represent the 3D shapes of molecules Wedges and dashed/dotted bonds are used

Answer 8

A bond in the direction behind the plane of the paper

Answer 9

A bond in the direction in front of the plane of the paper

Answer 10

An organic molecule/hydrocarbon containing 1+ benzene rings

Answer 11

A **modifier** responsible for the **characteristic chemical reactions**/behaviours of molecules that contain it

Answer 12

Series of compounds in which **all members have the same functional group** but have different carbon chain lengths

Answer 13

A compound containing only carbon and hydrogen (May be used to refer to a section of a molecule)

Answer 14

A saturated hydrocarbon where the carbon atoms are joined in a ring

Answer 15

Have the general forumla **C_nH_2n** Have names begining with cyclo- Have names ending in **-ane** Are **saturated** - all bonds betweens Cs are single Are **aliphatic**

Answer 16

An **unsaturated hydrocarbon** containing 1+ **C=C** bonds

Answer 17

Have the general forumla **C_nH_2n** Have names ending in **-ene** Are **unsaturated** - Have 1+ double bonds between C atoms in molecule Are **aliphatic** - don't contain benzene rings

Answer 18

Have names ending in **-ene** The **number preceeding the -ene indicates the position of the double bond** If there is more than 1 double bond there will be more than 1 number. Di, tri, tetra will be used before the suffix if this is the case

Answer 19

All bond angles around C=C bond **120º** Because there are **3 groups of e^- around each C atom** - 2 single bonds + 1 double bond These groups **repel** each other as far as possible

Answer 20

A C=C bond contains a sigma (σ) bond and a pi (π) bond. A **σ bond** is an area of **increased e^- density between the C atoms**. Only contains 1 area of negative charge A **π bond** consists of **2 areas of negative charge**. One of these is **above the line of the atoms** and the other is **below**

Answer 21

σ bonds found in single bonds π bonds found in double bonds (along with a σ bond)

Answer 22

A positive ion or molecule with a **partial positive charge on one of the atoms** This causes it to be attracted to a negatively charged area It will react by **accepting a lone-pair** to form a dative covalent bond

Answer 23

A reaction in which an **electrophile joins** onto an alkene/**molecule with double/triple bond** **No atoms are removed** from the alkene/molecule it joins on to

Answer 24

If the electrons are unevenly distribute between the atoms

Answer 25

A molecule containing a carbon that has a positive charge It is formed as an intermediate in electrophilic addition

Answer 26

* The bromine molecule approaches the alkene + **negative electron sink** * This causes the electrons in the bromine molecule are **repelled** back along the molecule causing the electron density to become unevenly distributed. It is **polarised** * The bromine atom **nearest the alkene** becomes **slightly +ively charged** and acts as an **electrophile** * A **pair of e^-** from the alkene moves towards the **Br^δ+** and a **C-Br bond** is formed * The carbon species is now a carbocation * The **other bromine**, now **negatively** charged, **bonds** with the **carbocation**

Answer 27

If Cl^- ions are present when ethene reacts with bromine, the molecule BrCH₂CH₂Cl forms as well as the expected BrCH₂CH₂Br This is because both Cl^- and Br^- ions can attack the intermediate carbocation I.e. when **other anions present**, **next anion will always to remaining side not added to**

Answer 28

Anion will always add (first) to the **end with the least steric hindrance** i.e. end with least atoms/molecules in the way

Answer 29

CH₂BrCH₂Br 1,2-dibromoethane ## Footnote **Room temp + pressure**

Answer 30

CH₃CH₂Br bromoethane **Aqueous** solution, **room temp + pressure**

Answer 31

CH₃CH₂OH ethanol **Phosphoric acid adsorbed onto silica** catalyst, **300ºC + 60atm** If **conc H₂SO₄** used then at **1atm** + **steam** used

Answer 32

CH₃CH₃ ethane If **Pt catalyst**, **room temp + pressure** If **Ni catalyst**, **150ºC + 5atm**

Answer 33

A molecule which is the starting material for a polymer Is **unsaturated**

Answer 34

A long-chain molecule formed when lots of small, repeating units called monomers join together They are **saturated**

Answer 35

Bromine - is decolorised if unsaturated. Goes from **brown** to **colourless**

Answer 36

In the presence of unsaturation, changes from **orange** to **colourless**

Answer 37

One type of alkene monomer -A-A-A-A-A-A- More than one type of alkene monomer (used in **copolymerisation**) -A-B-A-B-A-B-

Answer 38

Alkenes Because they contain a double bond and alkanes do not

Answer 39

The **polymer** and **no other products**

Answer 40

Addition polymers are **saturated** molecules The **monomers** used to make them are **unsaturated**

Answer 41

By putting the name of the **monomer** in **brackets** and prefixing with '**poly**' e.g. poly(cholorethene) HOWEVER the polymer itself is *not an alkene*

Answer 42

Only 2 carbons have bonds extending beyond the brackets. Further carbons 'branch' above/below the 2 main ones so there's never more than 2 'main' carbons in the brackets e.g. for poly(butene) the carbons are not in a long line of four, instead the other 2 carbons extend above/below the central 2 in the brackets

Answer 43

When **more than one type of monomer** is used during polymerisation Polymers have the general structure: -A-B-A-B-A-B-

Answer 44

A **polymer** that **returns to its original shape after being deformed** Are soft + springy

Answer 45

With a **Pt catalyst** - **room temp + pressure** With a **Ni catalyst** - **high temp + pressure** (100-200ºC + 2-10atm)

Answer 46

Molecules with the **same molecular formula** but which have **different structural formulae** 3 types: **chain** isomerism, **position** isomerism, **functional group** isomerism

Answer 47

Shows the numbers of each type of atom in a molecule e.g. C₆H₁₂ **Do not indicate functional groups** e.g. the proper molecular formula of ethanol is C₂H₆O not C₂H₅OH

Answer 48

The **different arrangement arrangement of carbon atoms in a chain**. **Chain lengths are different**/carbons are in different places in the chain because of **branching** e.g. butane + methylpropane both have the molecular formula C₄H₁₀

Answer 49

Where the **functional group is situated in different places**/potitions in the molecule e.g. propan-1-ol + propan-2-ol both have the molecular formula C₃H₈O

Answer 50

Compounds have the **same molecular formulae** but have **different functional groups** e.g. propan-1-ol + methoxyethane

Answer 51

Molecules with the **same molecular formula** but **different arrangements of the atoms in space** (different 3D structure) Excludes any different arrangements due to the molecule rotating as a whole or rotating about particular bonds. *Not the same as structural isomerism!*

Answer 52

Geometric isomerism AKA cis-trans/**E-Z isomerism**

Answer 53

A **double bond** between 2 carbon atoms 2 different groups on each double-bonded carbon *(e.g. cannot have 2 different groups on only 1 carbon/end)*

Answer 54

Groups on the **same side** of the double bond

Answer 55

Groups on **opposite sides** of the double bond

Answer 56

The **highest priority groups** are on **opposite sides** of the double bond

Answer 57

The **highest priority groups** are on the **same side** of the double bond *(think zame zide...)*

Answer 58

**Trying to rotate the carbon-carbon double bond would break the pi bond** as the p orbitals forming it wouldn't line up any more. This **requires energy** and only happens if the compound is heated strongly. There's not enough energy at room temp for this to happen Hence interconversion of the two isomers doesn't occur

Answer 59

**ΔH for any reaction will be the same** regardless of any intermediate stages provided the **start + end conditions/points are the same**

Answer 60

ΔH₁ = ΔH₂ - ΔH₃

Answer 61

0 Because forming an element from the same element requires 0 energy So you **don't need to include the value in Hess' Law calculation**

Answer 62

**Construct an enthalpy cycle**. Make sure the arrows point the correct way to represent the enthapy changes occuring **Choose suitable labels** for each arrow e.g. ΔH₁ etc. **Calculate ΔH₂** = -227kJmol^-1 **Calculate ΔH₃** = 2x-394 + 3x-286 = -1646kJmol^-1 Use the **general equation** for Hess' Law to find **ΔH₁ = ΔH3 - ΔH****2***(**ΔH₁ is the unknown*) ΔH₁ = -1646 - (-277) = **-1369kJmol^-1**

Answer 63

If **Δ_fH** data is given, **elements** will be on the bottom and arrows will be pointing **up** If **Δ_cH** data is given, **combustion products** will apeear at the bottom and arrows will be pointing **down**

Answer 64

The amount of energy produced per kg of fuel

Answer 65

The **energy required to break** **1mol** of a particular bond. **Averaged** over a range of **different gasous compound**s containing that bond (Basically it's a measure of strength of a covalent bond)

Answer 66

**Draw diagrams** to show the structures of the reactants + products **List the bonds broken:** 1x C-C = +347 6x C-H = +2478 3.5x O=O = =+743 **Total = +4568** (**+** sign because bond **breaking**) **List the bonds formed:** 4x C=O = -3220 6x O-H = -2784 **Total = -6004** (**-** sign because bond **making**) **Add together** the enthalpy changes for bond breaking + making: ΔH = =4568 + (-6004) = **-1436kJmol^-1**

Answer 67

**Average bond enthalpies** from several compounds are used in the caluclation - the actual bond enthalpies in particular molecules will be vary slightly Bond enthalpy data are for **gaseous molecules** - some molecules may be in different states (e.g. liquid) at 298K

Answer 68

The **higher** the bond enthalpy, the **shorter** the bond

Answer 69

**Double + triple bonds** have **higher bond enthalpies** than single bonds

Answer 70

Attractive + repulsive forces

Answer 71

Difficule to measure as there is often **more than one type of bond** in a compound Hence an **average** taken across several different compounds

Answer 72

A reaction that breaks large molecules into smaller ones

Answer 73

**Crude oil** contains **too many high bp fractions** + **not enough low bp fractions** to meet **demand** '**Straight-run**' gasoline from primary distillation is **poor quality** + needs refining further

Answer 74

Substance which **speeds up the rate** of chemical reaction by **providing an alternate reaction pathway** with a **lower E_A** Is **not chemically changed**/used up at the end of the reaction (Although may form **intermediates** or be **poisoned**)

Answer 75

The acceleration of a chemical reaction by a catalyst 2 types - heterogenous + homogeneous

Answer 76

It **doesn't**! The enthalpy change remains the same

Answer 77

A catalyst which is in the **same physical state** as the reactants

Answer 78

A catalyst which is in a **different physical state** to the reactants

Answer 79

A substance which **irriversibly binds** to the catalyst surface, **blocking its active site** and stopping it from functioning properly Prevents/**inhibits** other/fewer reactants being **adsorbed** so the catalyst becomes less efficient

Answer 80

A **heterogeneous** catalyst The **reactants** are the **exhaust fumes** whilst the **catalyst** is a solid (finely-divided) **metal** (e.g. Pt/Rh)

Answer 81

Catalyst poisons

Answer 82

Lead poisons the metal catalytic converters found in cars (e.g. Pt/Rh)

Answer 83

Must not have a calatyst poison bound to it Must have a l**arge surface area** in order to **adsorb** reactants. Hence they are used in a **finely-divided** form, often on a **porous support** material

Answer 84

1. Reactants come into **contact** with catalyst **surface** 2. Reactants **adsorbed** onto catalyst surface. This **weakens** intramolecular **bonds** 3. **New bonds form**, creating the products of the reaction 4. **Products diffuse away** from the catalyst surface, leaving it **free** for **new reactants** to **adsorb** to

Answer 85

They provide a **surface on which a reaction may take place** This **lowers the E_A** needed for a successful collision + means the reactants are **more likely to collide** (which will result in a successful reaction if they have the E_A or above)

Answer 86

1. If using a liquid alkane mixture: Place 2 cm depth of **mineral wool** into a **boiling tube**, then use a dropper pipette to add approximately **1 cm³ of liquid alkane mix**. Rotate the tube to ensure that the liquid alkane mixture soaks into the mineral wool. 2. Set up the apparatus as shown in the **picture** 3. Use a spatula to place some of the **catalyst** into the **middle** of the reaction tube. Keep it **separate** from the alkane mixture + mineral wool. Make sure there is **space above** the catalyst for **gases to pass freely over it**. 4. **Heat** the **catalyst strongly** with a **Bunsen** flame. Once it's hot, **gently warm** the **alkane** mixture to produce alkane **vapour**. 5. Move the Bunsen burner backwards and forwards between the catalyst and the alkane mixture until you have **collected several tubes of gas**. Stopper the tubes for testing later. The first tube can be discarded because it will contain mainly displaced air from the apparatus 6. Do not allow water to **suck back** from the trough 7. When finished, lift the delivery tube out of the water + leave the apparatus to **cool** before **dismantling it in a fume cupboard**

Answer 87

**Flammability**: For solids + liquids, place a spatula end or a few drops of the substance into a **combustion spoon\*** (or dip a glass rod in) and hold in a **Bunsen flame**. For gases, use a lit splint to see if the gas is flammable. Test with **bromine water**: For solids + liquids, place a spatula end/a few drops of the substance into a **test tube**. Use pipette approximately **1 cm³ bromine water** in, stopper the tube, and **shake** to mix. For gases, add approximately **1 cm³of bromine water directly** to the tube, stopper the tube, and **shake** to mix. *\*see photo for picture of combustion spoon*

Answer 88

6.02x10²³ Always equal to **Avogadro's constant**

Answer 89

The volume of any gas at RTP will be **24dm³** Means 1mol of any gas occupies same vol so long as conditions the same *RTP = 1atm, 293K*

Answer 90

**PV = nRT** P= pressure (**Pa**) V = vol (**m³**) n = moles R = gas constant T = temp (**K**)

Answer 91

**Moles = vol (dm³) / 24.0** So vol = moles x 24.0

Answer 92

**1,000dm³** So 1m³ = 1,000,000cm³ *(1000dm³ x 1000)*

Answer 93

Using a **gas syringe** Using an **inverted burette/measuring cylinder**

Answer 94

Whether the gas is more/less dense than air - hence whether to use downward/upward delivery If the gas is soluble in water *Regardless, the reaction **may not go to completion**, so the **vol gas evolved** may be **lower** than expected*

Answer 95

Up to **100cm³** gas can be colleced Can be measured to the **nearest 1cm³** Can be used if **gas soluble in water** Can be used for collection of **all gases regardless of density**

Answer 96

**Burette** can collect up to **50cm³** gas and measure to the **nearest 0.1cm³** A **measuring cylinder** can collect **greater volumes** (although only measures to **nearest 1cm³ like syringe**) Can be used for **downward delivery** if gas more dense than air

Answer 97

1. Place a **measuring cylinder filled with water upside down in a water trough** so the water doesn't escape from the measuring cylinder. 2. **Clamp** the measuring cylinder in place so that it **cannot topple** over. 3. Add a **delivery tube** to the bottom of the measuring cylinder so gas collected will go into cylinder. 4. Add **reactants** to conical flask one after another and place a **bung** on top of the flask immediately after **so no gas can** escape. 5. The volume of gas evolved can be measured by recording the amount by which the water in the cylinder has moved down.

Answer 98

1. Attach the **gas syringe** to a **delivery tube**. Attach the other end to a **bung** 2. Push the **plunger** in as far as possible (so it's at 0, or record the starting point) 3. Mix together the **reactants**, then quickly replace the **bung** so no gas escapes 4. Record the volume of gas evolved once the reaction has gone to completion

Answer 99

A pollutant **released directly** into the atmosphere

Answer 100

A pollutant not released directly into the atmosphere Instead **formed from primary** pollutants in the **atmosphere**

Answer 101

In: fuel + air Out: CO₂, CO, H₂O, SO_x, NO_x, N₂, particulates, unburnt hydrocarbons

Answer 102

Smog containing **mix of primary + secondary pollutants** which **absorb light energy** and undergo chemical **reactions**, forming smog

Answer 103

* Produces ozone + other secondary pollutants/irritating chemicals * Ozone is a greenhouse gas + damages lung tissue/immune system * Haziness + reduced visibility * Eye + nose irritation * Difficulty breathing * Harmful to plants + animals * Damages substances with C=C bond (e.g. plastic + rubber)

Answer 104

Small carbon particles smaller than **2.5x10^-12m** Formed from **burning fossil fuels** + **volcanoes** Penetrate the body causing **lung cancer** + **heart attacks** Make surfaces **dirty**

Answer 105

Formed from **incomplete combusution/leakage** from fuel tanks Can go on to form **photochemical smog**

Answer 106

**Incomplete combustion** of hydrocarbons, burning biomass Is a **toxic gas** + can form **photochemical smog** **Catalytic converters oxidise** CO to CO₂

Answer 107

Formed from the **complete combustion** of hydrocarbons Is a **greenhouse gas** + causes **global warming**

Answer 108

Formed from the reaction of **oxygen + nitrogen** (from the **air**) at **high temps in car engines** **NO oxidised to NO₂** by O in the air. NO₂ linked to **respiratory illnesses** (e.g. asthma + bronchitis) **NO_x** **dissolve** in rain water causing **acid rain** + can cause **photochemical smog** **Catalytic converters reduce NO** to N₂

Answer 109

Formed from the **oxidation of sulfur impurities in fuels** + **volcanoes** Cause **acid rain** + are **toxic gases** Can remove sulfur before burning - **desulfurisation**

Answer 110

Particulates CO NO₂

Answer 111

Unburnt hydrocarbons CO₂ SO_x (acid rain) NO_x (when causing acid rain)

Answer 112

Breathing difficulties Kills forests + lake life Corrodes limestone buildings

Answer 113

Using **oxygen** to turn **CO** into **CO₂** Using oxygen to turn **hydrocarbons** into **CO₂ + H₂O** Reacting **NO** with **CO** to form **CO₂ + N₂**

Answer 114

**Pt/Rh catalyst** Are a **fine powder**, spread over a **ceramic support** with many **tiny pores** forming a honeycomb structure Need to placed in the **correct position** so they **don't interfere with stoichiometric air-petrol mixture** for **optimum fuel consumption**

Answer 115

When burnt release as much CO₂ as absorbed when (plant) growing/created No net increase in production of CO₂ - that absorbed balances that produced *A fuel can only be considered this if its production, **trasportation**, etc. are also carbon neutral*

Answer 116

Able to be used without having a negative impact on future generations

Answer 117

A resource that will run out

Answer 118

No - crude oil is running out

Answer 119

**Less CO₂** produced than petrol engine, **already sold** at petrol stations Produces **more NO_x + particulates** than petrol engine, **not sustainable**

Answer 120

No - crude oil is running out

Answer 121

**Less CO, CO₂, C_xH_y, + NO_x** than petrol engine, petrol engines **easily converted** to use it Needs to be **stored under pressure** so it's a **liquid**, **not sustainable**

Answer 122

Possibly not - Large amounts of **energy** needed for **cultivating sugar cane** for fermentation

Answer 123

**Less CO, SO₂, and NO_x** than car engine, sugar cane **absorbs CO₂ when grown** (could be carbon neutral), **high octane number** (higher performance fuel) Highly **flammable**, engine **cannot run on it alone** (max 15%), land could be used for **farming** etc.

Answer 124

**Renewable** as can be made from **waste plant/animal oils + fats** BUT **fossil fuels** may be used as **energy source** in production But **potentially**, yes!

Answer 125

Living things have **absorbed CO₂**, **biodegradable**, **less CO, C_xH_y, SO₂, + particulates than disesel** engine **Higher NO_x** emissions than **diesel** engine, **not necessarily sustainable** depending on energy source used to produce

Answer 126

Only if the **electricity** needed for **electrolysis of water** is from **renewable** source (e.g. solar cells)

Answer 127

**Water** is the **only product of combustion**, may be **sustainable** Highly **flammable**, **high-prssure tank** needed to store it as a **liquid** (otherwise cannot be used)

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Developing Fuels Flashcards

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