Question | Answer |
Describe the difference between an AlkAne and an AlkEne | Alkane have only single C-C bonds whilst Alkenes have at least one double C=C bond |
Write the balanced equation for the COMPLETE combustion of Hexane | C6H14 + 6.5 O2 --> 6 CO2 + 7 H2O
It is quite fine to use .5 of a mole! |
Write the balanced equation for the COMPLETE combustion of Hexanol | C6H13OH + 6 O2 --> 6 CO2 + 7H2O
when you were balancing the Oxygen atoms, did you remember that the Alcohol already brings 1 Oxygen atom? |
Name 3 ways of making a fuel more efficient | isomerisation, reforming, shortening chain |
What is isomerisation? | 2 chemicals with same molecular formula but different arrangement of the atoms |
What is a catalyst (4 points)? | speeds up reactions, without getting used up (mass stays same), by lower activation energy and taking an alternative reaction pathway |
What is HETEROGENEOUS catalyst? | when the reactants and the catalyst are in different states |
Describe how a heterogeneous catalyst works? | reactants form BONDS with surface of catalyst (aDsorbtion), BONDS WITHIN reactants weaken/break; new BONDS BETWEEN reactants form; BONDS PRODUCTS-SURFACE weaken and products DESORB
Note: it is all about BONDS!!! Check you write aDsorbtion not aBsorbtion |
How is this pollutant formed? CO | INCOMPLETE combustion of fossil fuels, when Oxygen is in short supply |
How is this pollutant formed? CO2 | COMPLETE combustion of fossil fuels, when Oxygen is in excess |
How is this pollutant formed? particulates | INCOMPLETE combustion of fossil fuels, when Oxygen is in short supply |
How is this pollutant formed? NO | in HOT engine when oxygen FROM THE AIR reacts with Nitrogen FROM THE AIR |
How is this pollutant formed? NO2 | Further oxidation of the NO |
How is this pollutant formed? SO2 | combustion/oxidation of impurities found in Fossil fuels |
What is a catalyst poison? | a chemical that binds permanently to teh surface of the catalyst; preventing reactants to bind |
Describe the cracking experiment | vapours of a long chain alkane are passed over a HOT aluminium oxide catalysts |
Write the balanced equation for the cracking of Hexane | C6H14 --> C2H4 + C4H10 |
What is Carcking? | A long chain hydrocarbon has been broken into two smaller molecules: a smaller alkane and an alkene |
Write the balanced equation for the reforming of Hexane | C6H14 --> C6H12 + H2 |
What is reforming? | formation of a benzene ring |
Write the balanced equation for the isomerisation of Hexane | Hexane --> Methyl-2 Pentane |
What does TEACUPS stand for? | Transport Energy Availibility Cost usable Pollution Safety |
Which fuel has the highest energy density? | Hydrogen |
Which fuel can make engines corrode? | Ethanol |
Explain how fractional distillation works, in terms of intermolecular forces | LONGER chains of Hydrocarbons have a higher b.p. because there are more points of CONTACT between molecules so the VdW forces BETWEEN MOLECULES will be stronger so it will take more ENERGY to separate the molecules. |
Explain why branched Alkanes have a lower b.p. than the straight chain isomer, in terms of intermolecular forces | STRAIGHTER chains of Hydrocarbons have a higher b.p. because there are more points of CONTACT between molecules so the VdW forces BETWEEN MOLECULES will be stronger so it will take more ENERGY to separate the molecules.
Also less packing=less VdW |
What is the effect of CO2 on the environment? | Enhanced Greenhouse effect |
What is the effect of CO on the environment? | Toxic gas |
What is the effect of NOx on the environment? | Dissolves in WATER in clouds to produce Nitric Acid, part of Acid Rain |
What is the effect of SO2 on the environment? | Dissolves in WATER in clouds to produce Sulfuric Acid, part of Acid Rain |
Why do are Rhodium and Platinum catalysts placed on a honeycomb structure in a catalytic converter? | To provide a larger surface area |
Why does Petroleum Industry uses reformation, cracking and isomerisation? | To make fuels more efficient |
What is the equation to show how a catalytic converter converts NO and CO into harmless gases | 2 NO + 2CO --> 2 CO2 + N2
Did you get the formula of Nitrogen gas correct? |
Write the equation for the INCOMPLETE combustion of Hexane to produce Carbon Monoxide and Water only | C6H14 + 6.5 O2 --> 6 CO + 7 H2O |
What is a biofuel? | A fuel made from part of a plant or animal waste |
Why do Alcohol, such as Ethanol, burn more efficiently? | There is already an Oxygen in the molecule of Ethanol |
State advantages of using biofuels compared to Fossil Fuels | Biofuels use renewable resources; they burn more efficiently; they are Carbon-Neutral; Saves finite resources (Crude Oil) for other purposes (making plastics) |
State disadvantages of using biofuels compared to Fossil Fuels | Land is needed for growing crops for biofuels: this may lead to deforestation; or that land is not cultivated for food: which in turn can lead to food shortages and food prices going up; the process of making biofuel is not exactly Carbon-Neutral |
What is the name of the process by which biofuel/Ethanol is produced from Sugar cane? | Fermentation |
What are the conditions for fermentation? | Yeast at a temperature between 25-45C; anaerobic (without Oxygen) |
What is the equation for the fermentation process? | C6H12O6 --> 2CO2 + 2C2H5OH |
Why is the process of making biofuel not completely Carbon-Neutral? | Energy is needed for distillation process , transport of the raw materials to the factory |
What is the SOLID chemical formed by incomplete combustion? | Carbon |
What is the hazard linked to soot/carbon/particulates produced during incomplete combustion? | irritates the lungs |
One mole of an ALkane is cracked: two moles of Ethene, one mole of But-1-ene and one mole of octane are produced. What is the molecular formula of the AlkAne? | C16H34 (ALWAYS write the equation in the margin or rough paper) |
What is the metal used in catalytic converter? | Platinum |
Why is the boiling point of a straight-chain alkane higher than the corresponding branched isomer? | 1)Chains can move closer together/more points of contact; 2) higher VdW BETWEEN molecules; 3) more energy needed to break APART the MOLECULES |
What is the equation for the formation of Nitric Acid from Nitrogen Dioxide? | 2 NO2 + H2O + 1/2 O2 --> 2HNO3 ; NOTE that there is Oxygen involved! |
What is the equation for the neutralisation of Sulfuric Acid by Calcium Carbonate? | H2SO4 + CaCO3 --> CaSO4 + H2O + CO3 |
What is the equation for the neutralisation of Sulfur Dioxide by Calcium Carbonate? | SO2 + CaCO3 + 1/2 O2 --> CaSO4 + CO2 NOTE that there is Oxygen involved! |