User:Adamroy136

biofuel is a fuel. A fuel is something that releases energy when burnt. Biofuels are not used as the main full source because it doesn’t produce as much energy as fossil fuels this is an advantage of using fossil fuels because it is quicker and less time to create more energy this means that biofuels are not as useful for society. Fossil fuels is a limited source and will run out whilst biofuels are renewable so they will never run out this has a positive effect on society. Fossil fuels also release more carbon dioxide than fossil fuels this means that biofuels are good for the environment. Biofuels are already used as fuels in Brazil but the fuel is made up of 85% biofuel and 15% oil this keeps costs down and still releases a good amount of energy. Biofuels can be used as a fuel but it is also used in drinks, hand gel and solvents. Fossil fuels are found under ground and are made by animal and plant remains being put under lots of pressure and heat for millions of years. Biofuels are made by fermenting plants usually sugar cane. Fermenting is a chemical breakdown of a substance using microorganisms usually bacteria or yeast. Incomplete combustion is when something is being burnt without enough oxygen this produces carbon monoxide or just carbon. When it is burnt in a plentiful supply of oxygen it produces carbon dioxide. Biofuels are sustainable this means that they can be used now but still have a plentiful supply for future generations. Biofuels are also renewable. Renewable means to be able to make the same product again and again without it ever running out. Other examples of renewable energy are: wind, solar and hydroelectric power. Biofuels when burned release carbon dioxide and water this is the equation for burning bioethanol: biomethanol+oxygen→carbon dioxide+water Biofuels are also part of the carbon cycle because they release carbon dioxide when burnt. They get the carbon from the glucose in the sugar cane. The sugar can get there glucose from the carbon dioxide in the air through a process called photosynthesis. This is the equation of photosynthesis: glucose+water( light) ⃑ Glucose+oxygen When growing needs land kill animals.

Alcohols are very useful one of their best uses being as a more environmentally friendly fuel when compared to fossil fuels. Alcohols are very flamabe this helps them be a better fuel. When Alcohol is brurned and rects with enough oxygen to fully combust it produces Carbon Dioxide and water. Every alcohol ends with the two letters “ol”. Every alcohol has a hydroxyl functional group. This consisted of one oxygen atom joined to hydrogen. he general formula for a Alcohol is:     C_(n ) H_(2n+1) OH The enthalpy of combustion is the enthalpy of combustion is the enthalpy change when one mole of a substance burns completely in oxygen. The enthalpy change can be worked out by:

∆H=cm∆T

The enthalpy change is also equal to the bond enthalpy. You work out the bond enthalpy by doing: C2H5OH     +     3O2                   2CO2         +       3H2O Bond Breaking (endothermic) kJmol^(-1)	Bond Making (exothermic) ) kJmol^(-1) 5 x (C-H)=(5 x 412)=2060 1 x (C-O)=(1 x 360)=360 1 x (O-H)=(1 x 463)=463 1 x (C-C)=(1 x 348)=348 3 x (O=O)=(3 x 498)=1494	4 x (C=O)=(4 x 743)=2972 6 x (O-H)=(6 x 463)=2778 Total = 4725	Total = -5750 ∆H=4725+(-5750)=-1025) kJmol^(-1) London Dispersion Forces create a temporary dipole and are the weakest of all the intermolecular forces. The temporary dipoles arise when all the electrons go to ones side of the atoms causing it to have a dipole for a short amount of time. Permanent dipole – permanent dipole are the second strongest intermolecular force. This arises when one atom have got a large difference in electronegativity. Hydrogen bonding is the strongest bonding and is the main intermolecular force in alcohols. This occurs when one atom has a much higher electronegativity then hydrogen and is bonded to it. The only elements this happens is: Fluorine, Oxygen and Nitrogen. This is present in alcohols because of the hydroxyl group it has. Alcohols can be split into 3 groups: Primary, Secondary and tertiary Alcohols. Primary alcohols are when the hydroxyl group is connected to a carbon with two or more hydrogens attached. Secondary is when one hydrogen is attached to the carbon attached to the hydroxyl group Tertiary is when no hydrogens are attached to the carbon attached to the carbon attached to the hydroxyl group. Oxidising alcohols this is when Alcohols loss hydrogens to become a different group of molecules. This is what happens to each type of alcohol whe it ges oxidised Primary Alcohol  Aldehyde  carboxylic acid Secondary Alcohol  Ketone  Nothing Tertiery Alcohol  Nothing This source comes from a experiment done in class it was designed to with the aim of “To find out how the amount of carbons effect the enhanpy of combustion.” The indepentant variable was the amount of carbons and the dependant variable was the change in mass which allowed me to calculate the enthalpy change.

in my method Get all equipment and set it up like the digrame Meaure 100cm3 of water and place into the coper can Weigh the alchol burner and take note of the reading make sure to keep the cap on so no alchol is lost to evaphoration Place the alcohol under the copper can and take note of the temperature of the water and then light the alchol. Wait till the waters temperature has rised by 10 ⁰C Then repeat a further 2 times and do this for each alcohol

in risk assessment One risk is that the alcohols are very flammable and you are working with fire so keep the alcohol away from the fire and make sure the cap is secur after ever experiment so no evapour gets out and is set on fire. When working with fire had no loose clothing or long hair that isn’t tide back incase it gets set on fire. So take of or tuck in scurfs, tie and any other loose clothing. Tie your hair back using a bobble.

my data biomethanol started 173.48 173.26 173.03          strt temp 22 22 22                 end temp 32 32 29 ended 173.26 173.03 172.90          change mass 0.22 0.23 0.13        change temp 10 10 7 bioethanol started(g) 159.90 166.13 165.98          strt temp 22 20 21                 end temp 27 30 29 ended (g)159.48 165.98 165.82           change mass 0.22 0.15 0.16         change temp 10 10 8 biobutanol start(g) 98.76 98.58 98.29            strt temp 20 20 21                   end temp 35 37 38 ended (g) 98.58 98.29 98.04           change mass 0.18 0.29 0.25           change temp 15 17 15

CMΔT M = mass of water (0.05kg) C= 4.18 ΔT= change in temp

I choose this source because it is from a educational site that the author Nigel Saunders is a respected scientist with a doctoret.

In conclusion increasing the number of carbon atoms in an alcohol increases the enthalpy of combustion.

In 1 it was a experiment which was done in class with a limited amount and quality of equipment this meant that there was energy lost to the surrounding and incomplete combustion. The incomplete combustion was indicated by the black suit (Carbon). This could be helped by using pure oxygen and just burning it in a space with a higher concentration of oxygen than the air. This would means that there would be complete combustion ad therefore no black carbo at the base of the can. Losing energy to the environment happened and you can tel this because all of sources 2 were much bigger than source 1 this shows that some of the energy would have been lost to the air. This could have been avoided by making the gap between the flame and the can smaller. This could also have been avoided by using a draft shield so that more energy goes to the can and can be conducted to heat up the water. Another way of avoiding losing energy to the environment is by using a bomb calorimeter. This has a heater in the midlle of water so no heat is lost in the air. This means that it takes less time and takes less energy. Another thing I could do to improve my experiment is remeasure and use different water for each reading. This could theroretical cause the waters volume to decrease and therefore meaning that there is less energy needed to make the water raise by 10°C. This could cause my readings to be less accurate because the volume of water wouldn’t be the same everytime. This could be fixed by using different water from the tap each time.

Bibleography: Class experiment Enthalpy of combustions of alchols aim of “To find out how the amount of carbons effect the enhanpy of combustion.” https://www.creative-chemistry.org.uk/gcse/documents/Module7/N-m07-24.pdf# https://www.bbc.co.uk/education/guides/zyq22hv/revision http://www.bbc.co.uk/schools/gcsebitesize/science/triple_aqa/alcohols_carboxylic_acids_esters/alcohols/revision/1/ https://www.chemguide.co.uk/organicprops/alcoholmenu.html https://www.masterorganicchemistry.com/2014/09/17/alcohols-1-nomenclature-and-properties/ https://www.understandingstandards.org.uk/Higher_images/chemistry/assignment/HigherChemistryAssgn2015EvidenceCandidate3A.pdf