For the last 6 markers, I said that B was the best choice as it was 61p cheaper than C, had the best cost per wash, and was almost identical to C apart from 1 point of in terms of whiteness.
How do you think the grade boundaries are gonna be this year? High? Low? I can't tell as I've seen a mixed review on how people found the paper
I think the grade boundaries will be high because the exam was easier than previous papers; but i dont think it will increase by a lot just marginally, like 1 or 2 marks.
For the last 6 markers, I said that B was the best choice as it was 61p cheaper than C, had the best cost per wash, and was almost identical to C apart from 1 point of in terms of whiteness.
the question specifically said what was the best detergent to wash with, our teachers have always drilled into our head that cost should never be a factor when choosing the better one as it's not an economic exam
For the last 6 markers, I said that B was the best choice as it was 61p cheaper than C, had the best cost per wash, and was almost identical to C apart from 1 point of in terms of whiteness.
That is what i said too so hopefully someone sees our way of thinking
Also with the concentration question i was so confused because despite the concentration changing, they used the same volume of acid so shouldnt the amount of gas produced still be the same, just have a faster rate of reaction. that is what we were taught for c3 anyways
C4 Question about ions and atoms - Mg+ (1) - MgFl2 (1)
Why and how do Lithium atoms form ions -It loses electrons to become stable (1) -It loses one electron: Li- -> Li + e- (1)
Draw Na20 -dot and cross diagram with 2- charge on Oxygen atom and +1 charge on both sodium atoms
Table to fill in with Protons, Neutrons (2) Protons: 1, +1 (1) Neutrons: 1, 0
Why is the atom neutral? -It has the same number of protons as electrons (1)
Size of Atom- C forgot the q after that
What happened to Zinc Carbonate when heated (3) -Thermal Decomposition (2) -Zinc oxide and co2 emitted (1)
Predict the properties of ammonia (4) -Gas at room temperature -Doesn't conduct electricity -Low melting and boiling point due to weak IM bonds
Balancing: CaCO3 + 2HCl -> H20 + CaCl2 + CO2 (2)
6 marker on Halogens and reactivity -Reaction Cl2 + 2NaBr -> 2NaCl + Br2 -Order: Z (Fluorine) ,Cl,Y (Bromine),X (Iodine) (Dont have to name them) Explanation: Z displaced 3 solutions, Cl displaced 2, Y displaced 1 and X displaced 0
C5 Titration: 22 (1) 20(1)
30cm3 = 0.03 dm3 0.03*0.3= 0.009 mol (1)
Concentration is 0.45moldm-3 (2)
Percentage of Magnesium: 28.7% (not sure) (1)
Explain what is relative atomic mass: -Number of protons and neutrons
mass of hydrogen: 0.004g (2) -48cm3 = 0.048dm3 0.048/24= 0.002mol 0.002*2=0.004g
Contact Process question (screwed this one up)
Under what conditions and why the reaction is at equilibrium: -closed system (2) -forward reaction same as backward reaction (1)
Position of equilibrium when Oxygen is added: -Shifts to the right (1)
Conclusions about concentration of hydrogen: Both right i think (2)
6 marker on preparing insoluble salts Equation: Pb2+ 2I- -> PbI2 Method: Precipitate-add lead nitrate to distilled water and do the same with the other and tip both solutions to a small beaker Filter-put a piece of folded filter paper into funnel and stick funnel into conical flask and then swill out the beaker with more distilled water Dry- Rinse contents with distilled water to wash soluble salts away, leave it to dry C6 Rusting of iron equation: -Water + Oxygen + Water -> Hydrated Iron (III) Oxide (1)
Galvanising question: -Done with zinc and acts as sacrificial protection so it will lose electrons in preference to iron (1) -Acts as a barrier to water and air (1)
Redox reaction: oilrig cheeky mention -Reduction happens to Iron as it gains electrons (1) -Magnesium is oxidised as it loses electrons (1) Redox since both happening at same time
Alternative to ozone: -Alkane (1)
In terms of electons, how is Chlorine and Carbon bonds split: -Covalent bond is broken evenly where both chlorine and carbon get one of the electrons (making them both highly reactive as radicals) (2)
Why did attitudes to CFCs change (2) -They found out Chlorine from CFCs could destroy ozone -They found out that CFCs cause the depletion of Ozone Layer
Energy Level Diagram -Exothermic as energy is released, there is less energy in the product (1)
Fuel Cell Question: -O2 + 4H+ + 4e- -> 2H20 (2)
Which solution is temporary: -A as it had hardness before boiling and none after (2)
What causes permanent hardness in water -Calcium Sulfate (1)
6 marker on Detergents: -Peter was right as it had excellent whiteness and something else and had very good prevention of colour fading
-Detergents have a hydrophilic head and a hydrophobic tail. -Grease has weak IM bonds in between and so does the detergent -The detergent forms stron IM bonds with grease due to hydrophobic tail -Hence the detergent surrounds the grease and attaches to water -Lifting the grease off of the clothes
Dry Cleaning: -Solvent used is not water (1) -Water can damage delicate linen (1)
SECTION D idk
Relative atomic mass is wrong - it is the average mass of an element compared to the mass of 1/12th of an atom of Carbon-12
C4 Question about ions and atoms - Mg+ (1) - MgFl2 (1)
Why and how do Lithium atoms form ions -It loses electrons to become stable (1) -It loses one electron: Li- -> Li + e- (1)
Draw Na20 -dot and cross diagram with 2- charge on Oxygen atom and +1 charge on both sodium atoms
Table to fill in with Protons, Neutrons (2) Protons: 1, +1 (1) Neutrons: 1, 0
Why is the atom neutral? -It has the same number of protons as electrons (1)
Size of Atom- C forgot the q after that
What happened to Zinc Carbonate when heated (3) -Thermal Decomposition (2) -Zinc oxide and co2 emitted (1)
Predict the properties of ammonia (4) -Gas at room temperature -Doesn't conduct electricity -Low melting and boiling point due to weak IM bonds
Balancing: CaCO3 + 2HCl -> H20 + CaCl2 + CO2 (2)
6 marker on Halogens and reactivity -Reaction Cl2 + 2NaBr -> 2NaCl + Br2 -Order: Z (Fluorine) ,Cl,Y (Bromine),X (Iodine) (Dont have to name them) Explanation: Z displaced 3 solutions, Cl displaced 2, Y displaced 1 and X displaced 0
C5 Titration: 22 (1) 20(1)
30cm3 = 0.03 dm3 0.03*0.3= 0.009 mol (1)
Concentration is 0.45moldm-3 (2)
Percentage of Magnesium: 28.7% (not sure) (1)
Explain what is relative atomic mass: -Number of protons and neutrons
mass of hydrogen: 0.004g (2) -48cm3 = 0.048dm3 0.048/24= 0.002mol 0.002*2=0.004g
Contact Process question (screwed this one up)
Under what conditions and why the reaction is at equilibrium: -closed system (2) -forward reaction same as backward reaction (1)
Position of equilibrium when Oxygen is added: -Shifts to the right (1)
Conclusions about concentration of hydrogen: Both right i think (2)
6 marker on preparing insoluble salts Equation: Pb2+ 2I- -> PbI2 Method: Precipitate-add lead nitrate to distilled water and do the same with the other and tip both solutions to a small beaker Filter-put a piece of folded filter paper into funnel and stick funnel into conical flask and then swill out the beaker with more distilled water Dry- Rinse contents with distilled water to wash soluble salts away, leave it to dry C6 Rusting of iron equation: -Water + Oxygen + Water -> Hydrated Iron (III) Oxide (1)
Galvanising question: -Done with zinc and acts as sacrificial protection so it will lose electrons in preference to iron (1) -Acts as a barrier to water and air (1)
Redox reaction: oilrig cheeky mention -Reduction happens to Iron as it gains electrons (1) -Magnesium is oxidised as it loses electrons (1) Redox since both happening at same time
Alternative to ozone: -Alkane (1)
In terms of electons, how is Chlorine and Carbon bonds split: -Covalent bond is broken evenly where both chlorine and carbon get one of the electrons (making them both highly reactive as radicals) (2)
Why did attitudes to CFCs change (2) -They found out Chlorine from CFCs could destroy ozone -They found out that CFCs cause the depletion of Ozone Layer
Energy Level Diagram -Exothermic as energy is released, there is less energy in the product (1)
Fuel Cell Question: -O2 + 4H+ + 4e- -> 2H20 (2)
Which solution is temporary: -A as it had hardness before boiling and none after (2)
What causes permanent hardness in water -Calcium Sulfate (1)
6 marker on Detergents: -Peter was right as it had excellent whiteness and something else and had very good prevention of colour fading
-Detergents have a hydrophilic head and a hydrophobic tail. -Grease has weak IM bonds in between and so does the detergent -The detergent forms stron IM bonds with grease due to hydrophobic tail -Hence the detergent surrounds the grease and attaches to water -Lifting the grease off of the clothes
Dry Cleaning: -Solvent used is not water (1) -Water can damage delicate linen (1)
SECTION D idk
Fuel Cell Question: -O2 + 4H+ + 4e- -> 2H20 (2)
wouldn't it be O2 + 4H+ + 4e- -> 2H20 cause if there was an -O2 then the water will be a negative ion cause the electron balances the hydrogen ion.