Here is where ill attempt to make a rough mark scheme for the exam
First question about differences in processes of making fertilisers and drugs: Fertilisers need to be made on a large scale as they are bulk and millions of tonnes of them are used Drugs need to be very pure as they need to be safe for human consumption
Amount of different dyes: There were either 3 or 4 (up to debate)
Why is a locating agent used: A locating agent is needed as some of the dyes are invisible to the naked eye therefore the agent makes a coloured spot or makes it glow under UV light
How do you there was more of Dye C: Dye C had the greatest peak therefore the greatest recorder response which means it was the most detected chemical
How could Alex find out what dyes are being used: Alex could use the graph results and the results of known chemicals because he can cross-reference the two to find out what combination of known chemicals are in the sweet
What values are needed to calculate the retardation factor: The measurements needed are the distance between the start line and the centre of the spot (divided by) the distance between the start line and the solvent front
6 mark question about the reaction between methane and steam being unsustainable: Poor atom economy only 15% of the mass inputted is useful as the rest is wasted carbon dioxide The reaction requires high temperatures which is expensive to support Methane is a fossil fuel which is a finite source
The answers between the two came from NiamhM1801 and Username1502 big shoutout to them
Atom economy question: (Thanks to 11207ymir) 4/36 = 11.1%
The question about which one vinegar was: Circle D as this had COOH group at the end meaning it was the only carboxylic acid
What was the Ester made of: The ester was made from A and D
Question about the vertical condenser: This was talking about heating under reflux and how the reaction mixture (reactants + catalyst (sulfuric acid)) needs heat in order to react but the mixture is volatile so vaporizes easily therefore the condenser which is surrounded by cold water cools down the gases to form back into liquids and stay in the flask
Next question about Distillation and Purification: Distillation - Heating the reaction mixture to the boiling point of the ester so it turns into a gas then funneling this out through a condenser positioned so that the ester can travel to a different container and be separated from the remaining reactants and water. Purification - This where the ester is shaken with aqueous sodium carbonate this removes any acidic impurities by neutralizing it and moving it to the aqueous layer (lower layer) this is then runoff by a tap leaving the ester (organic layer) which can be removed of ethanol by shaking it with calcium chloride
Question about the bonds in Hydrogen Fluoride: Reactants: The H-H bond was 432 KJ/mol The F-F bond was 155 KJ/mol
The total energy for the reactants was 587 KJ/mol
Products: The H-F bound was 567 KJ/mol there was two of these bonds
The total energy for the products was 1134 KJ/mol
What was the energy change: 587 KJ/mol - 1134 KJ/mol = -547 KJ/mol Reactant + Products = Energy Change
The tick box question about the Haber Process: Increasing Temperature: Increases rate of reaction Increasing pressure: Increases Both Adding a catalyst: Increases (Rate of reaction or Both) Recycling the reactants: Increases yield
Chromatography what is the qualitative and quantitative analysis: Qualitative - Whether a certain dye is present or not, identifying a dye bye cross referencing its retention time with known retention times Quantitative - How much of the dye is present and the percentage make up of the entire compound by looking at the recorder response
Here is where ill attempt to make a rough mark scheme for the exam
Next question about Distillation and Purification: Distillation - Heating the reaction mixture to the boiling point of the ester so it turns into a gas then funneling this out through a condenser positioned so that the ester can travel to a different container and be separated from the remaining reactants and water. Purification - This where the ester is shaken with aqueous sodium carbonate this removes any acidic impurities by neutralizing it and moving it to the aqueous layer (lower layer) this is then runoff by a tap leaving the ester (organic layer) which can be removed of ethanol by shaking it with calcium chloride
Btw how many marks is this question I said everything except I said you heat it up but didn't mention heat it above ester boiling point and i said it produces an impure product when the vapour forms and condenses
Also for the tick the boxes question for harbour process won't adding a catalyst also increase yield as the activation energy is lower which therefore suggest more successful collisions occurring so more nh3 made
The energy change for the products should be -567 -567 = -1134 Hence the energy change should be 587 subtract (you are meant to subtract because overall energy change = bond breaking - bond making) -1134 so the answer is 1721
Energy is created when bonds are made, it is not negative because you can't create negative energy so 587-1134 is the answer
The energy change for the products should be -567 -567 = -1134 Hence the energy change should be 587 subtract (you are meant to subtract because overall energy change = bond breaking - bond making) -1134 so the answer is 1721
Here is where ill attempt to make a rough mark scheme for the exam
Next question about Distillation and Purification: Distillation - Heating the reaction mixture to the boiling point of the ester so it turns into a gas then funneling this out through a condenser positioned so that the ester can travel to a different container and be separated from the remaining reactants and water. Purification - This where the ester is shaken with aqueous sodium carbonate this removes any acidic impurities by neutralizing it and moving it to the aqueous layer (lower layer) this is then runoff by a tap leaving the ester (organic layer) which can be removed of ethanol by shaking it with calcium chloride
Btw how many marks is this question I said everything except I said you heat it up but didn't mention heat it above ester boiling point and i said it produces an impure product when the vapour forms and condenses
Also for the tick the boxes question for harbour process won't adding a catalyst also increase yield as the activation energy is lower which therefore suggest more successful collisions occurring so more nh3 made
negative energy is right. negative means its exothermic as energy is lost and positive is endothermic as energy is gained.
I meant the answer is 587-1134 which is a negative number when you do the calculation but the bond of the products is not negative but positive (+567+567) I was replying to message which said its (-567-567)
How did everyone find that? I'm so mad at myself. I revised so hard, and I got As and A*s in the past papers, but when it got down to the actual exam, I didn't finish it! I didn't finish the last double spread page, which was 7 marks and it looks like I've made a lot of mistakes in the parts I did do. This is probably the worst exam I've done so far. It wasn't even that difficult in retrospect. Ugh...