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# Gcse unit 2 chemistry aqa unofficial mark scheme+discussion

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1. It is for the mass of the nh3 question
2. (Original post by Queenz123)
I but 88% because 15/17 *100 gives you 88 %
It was (14/17) x 100 = 82.4% :-)

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3. (Original post by moolysk4)
It was (14/17) x 100 = 82.4% :-)

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But you had to do the overall ar of both elements so it would have been 15 not 14
4. (Original post by Queenz123)
But you had to do the overall ar of both elements so it would have been 15 not 14

No, it was 14/17. It was N/NH3

N = 14
H = 1

So 14 / 14 + (3 x 1) = 14/17
5. (Original post by Eldronyx)
No, it was 14/17. It was N/NH3

N = 14
H = 1

So 14 / 14 + (3 x 1) = 14/17
Would Get one mark for doing 14+(3*1)
6. i)Explain why Oxygen has a mass of 16.
Answer: I wrote because it's a mean of the most popular type of Oxygen?

ii) 12/6 C and 14/6 C are Isotopes of Carbon. Explain why include Sub-atomic particles in your answer.
Answer: I wrote about how protons are the same so they stay carbon but the neutrons (12 and 14) are different?

c)How does the increasing temperature affect the rate of reaction? You must refer to sub-atomic particles and collisions in your answer.
Answer: increasing temperature increases the activation energy so particles collide more frequently PER SECOND and therefore there are more successful collisions in a shorter amount of time so the rate of the reaction increases.

ii)Why does Magnesium move to the Negative Electrode in electrolysis? (3 Marks)?
Answer: Because opposite charges attract (I can't remember what else I wrote).

b) Why is Diamond Hard?
Answer: It has strong intermolecular bonds between the carbon atoms which take a lot of energy to break so they are hard to break?

c)Why are Thermosetting Polymers used as Saucepan handles instead of Thermoplastics (Thermosoftening)?
Answer: Thermosetting polymers have bonds between the layers which are hard to break so it has a high boiling point as it takes a lot of energy to break unlike thermosoftening polymers that have no bonds inbetween the layers therefore the layers can slide over each other so they have a low boiling point as it doesn't take much energy to break so if it was thermosetting it would melt.

Bulletzone
7. (Original post by LaurenHannahL)
i)Explain why Oxygen has a mass of 16.
Answer: I wrote because it's a mean of the most popular type of Oxygen?

ii) 12/6 C and 14/6 C are Isotopes of Carbon. Explain why include Sub-atomic particles in your answer.
Answer: I wrote about how protons are the same so they stay carbon but the neutrons (12 and 14) are different?

c)How does the increasing temperature affect the rate of reaction? You must refer to sub-atomic particles and collisions in your answer.
Answer: increasing temperature increases the activation energy so particles collide more frequently PER SECOND and therefore there are more successful collisions in a shorter amount of time so the rate of the reaction increases.

ii)Why does Magnesium move to the Negative Electrode in electrolysis? (3 Marks)?
Answer: Because opposite charges attract (I can't remember what else I wrote).

b) Why is Diamond Hard?
Answer: It has strong intermolecular bonds between the carbon atoms which take a lot of energy to break so they are hard to break?

c)Why are Thermosetting Polymers used as Saucepan handles instead of Thermoplastics (Thermosoftening)?
Answer: Thermosetting polymers have bonds between the layers which are hard to break so it has a high boiling point as it takes a lot of energy to break unlike thermosoftening polymers that have no bonds inbetween the layers therefore the layers can slide over each other so they have a low boiling point as it doesn't take much energy to break so if it was thermosetting it would melt.

Bulletzone

Diamond has strong covalent bonds not intermolecular bonds it is a giant structure not a molecule

increasing temperature does not increase the activation energy the activation energy is the amount of energy needed for particles to react. By increasing the temp a higher proportion of particles have the activation energy needed to react so more collisions result in a reaction
8. (Original post by LaurenHannahL)
i)Explain why Oxygen has a mass of 16.
Answer: Oxygen has a mass of 16 because it has 8 protons and 8 neutrons in it's Nucleus. The mass number is where all the mass lies which is in the nucleus as the weight of electrons are negligible.

ii) 12/6 C and 14/6 C are Isotopes of Carbon. Explain why include Sub-atomic particles in your answer.
Answer: I wrote about how protons are the same so they stay carbon but the neutrons (12 and 14) are different---this is generally correct

c)How does the increasing temperature affect the rate of reaction? You must refer to sub-atomic particles and collisions in your answer.
Answer: Increasing the Temperature provides more energy to the particle making them move faster than they original were before. Increasing the temperature increases the vibrations and speeds of particles which means more collisions are likely to occur, due to the fact a reaction begins when 2 particles collide with enough energy and supplying more heat increases the chances of doing so, thus increasing the rate of reaction.

ii)Why does Magnesium move to the Negative Electrode in electrolysis? (3 Marks)?
Answer: Because opposite charges attract (I can't remember what else I wrote). ----->That is okay

b) Why is Diamond Hard?
Answer: It has strong intermolecular bonds between the carbon atoms which take a lot of energy to break so they are hard to break and the Carbon atoms bond with other carbon atoms 4 times forming a very strong covalent bond.

c)Why are Thermosetting Polymers used as Saucepan handles instead of Thermoplastics (Thermosoftening)?
Answer: Thermosetting polymers have bonds between the layers which are hard to break so it has a high boiling point as it takes a lot of energy to break unlike thermosoftening polymers that have no bonds inbetween the layers therefore the layers can slide over each other so they have a low boiling point as it doesn't take much energy to break so if it was thermosetting it would melt.

Bulletzone
I've made amendments and I shall add the answers to the mark scheme later.
9. (Original post by LaurenHannahL)
i)Explain why Oxygen has a mass of 16.
Answer: I wrote because it's a mean of the most popular type of Oxygen?

ii) 12/6 C and 14/6 C are Isotopes of Carbon. Explain why include Sub-atomic particles in your answer.
Answer: I wrote about how protons are the same so they stay carbon but the neutrons (12 and 14) are different?

c)How does the increasing temperature affect the rate of reaction? You must refer to sub-atomic particles and collisions in your answer.
Answer: increasing temperature increases the activation energy so particles collide more frequently PER SECOND and therefore there are more successful collisions in a shorter amount of time so the rate of the reaction increases.

ii)Why does Magnesium move to the Negative Electrode in electrolysis? (3 Marks)?
Answer: Because opposite charges attract (I can't remember what else I wrote).

b) Why is Diamond Hard?
Answer: It has strong intermolecular bonds between the carbon atoms which take a lot of energy to break so they are hard to break?

c)Why are Thermosetting Polymers used as Saucepan handles instead of Thermoplastics (Thermosoftening)?
Answer: Thermosetting polymers have bonds between the layers which are hard to break so it has a high boiling point as it takes a lot of energy to break unlike thermosoftening polymers that have no bonds inbetween the layers therefore the layers can slide over each other so they have a low boiling point as it doesn't take much energy to break so if it was thermosetting it would melt.

Bulletzone
For the thermosetting & diamond I think you had to mention strong covalent bonds.

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10. i said insulation so the mixture will not be heated up by sorroundings as it was about temperature decrease will this work ?
11. (Original post by dh12345)
Diamond has strong covalent bonds not intermolecular bonds it is a giant structure not a molecule

increasing temperature does not increase the activation energy the activation energy is the amount of energy needed for particles to react. By increasing the temp a higher proportion of particles have the activation energy needed to react so more collisions result in a reaction
Diamond definitely has strong intermolecular bonds too, thats what makes it have high boiling and melting points, not the covalent bonds it has, even though it is covalently bonded
12. (Original post by mattedwards8972)
Diamond definitely has strong intermolecular bonds too, thats what makes it have high boiling and melting points, not the covalent bonds it has, even though it is covalently bonded
How can a bond between carbon atoms be intermolecular? one carbon atom is not a molecule where are the intermolecular bonds in diamond then? its a lattice structure

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