You should also be allowed 'add a lid' and 'insulate edges' with 'to reduce heat loss' for the 'how can you improve the accuracy of the experiment?' mark :smile:

Was there a question on what happens when magnesium bonds with chloride ions? I remember putting something about magnesium transferring one electron to each chloride atom, so the magnesium gets a +2 charge and the chloride atoms each get a -1 charge, and the strong electrostatic attraction between the oppositely charged ions holds them together.

Often for the conduction in a metal question you have to specifically state that the electrons are free to move through the structure carrying the charge.

Diamond you should mention that each of the carbon atoms is attached to four other carbon atoms (in a crystalline structure).

And the final question asked specifically why you would use thermosetting instead of thermosoftening; thermosetting don't easily melt because the cross-links between their polymer chains form strong covalent bonds throughout the structure, thermosoftening would melt with the heat of the pan because its polymer chains are held together by weak intermolecular forces between them and set in that shape when the pan cooled, deforming the handle.

Reply 127

powderpuff16

Original post by Naco88

They are the only 2 I saw.

could you do the concentration of them?

Reply 128

Naco88

Original post by powderpuff16

could you do the concentration of them?

Most likely yes :smile:

Reply 129

CaptErin

Original post by BDunlop

Wouldn't you have to say that sulfur is insoluble hence why you can see it, so surely it doesn't 'dissolve'?

Yeah I think you had to say that is formed an insoluble precipitate

Reply 130

barney.jones123

Is fossil fuels a source of methane?

Reply 131

powderpuff16

Original post by BDunlop

Wouldn't you have to say that sulfur is insoluble hence why you can see it, so surely it doesn't 'dissolve'?

Thats what i put

Reply 132

bamzy123

Original post by jackbarry1999

1b) use a digital thermometer ~ more accurate ~ no human error

What if you say use a thermometer with a higher resolution(has more numbers after the decimal)?

Reply 133

Katwamba01

Original post by Naco88

Sure

That reminds me, there was a question after when it asks you after what type of bond is water. It was 'Why doesn't pure water conduct electricity?'
My answer is: Because water has weak intermolecular forces, but have a strong covalent bond as the electrons are shared therefore the atoms have no charges and so water cannot conduct electricity. (Which I don't know if it's correct)

Correct answer:
Pure Water has a no ions.

(edited 7 years ago)

Reply 134

Actuvia

One of the question's in question 4 was something like:
What will raising the temperature do to the rate of reaction?
My answer was something along the lines of(in brief):
Gives particles more energy, particles move faster, more collisions occur, rate of reaction sped up

Reply 135

Dat1Guy

Original post by Certified

Electrolysis -

Gas produced was hydrogen
Why : H+ ions are more reactive than Mg^2+

Last question:

Copper can can conduct electricity due to free delocalised electrons that carry a charge, they move about the giant lattice.

Thermosetting is the better option because it can withstand high temperatures unlike thermosoftening. It has cross links made up of strong covalent bonds. They do not melt at high temperatures - high melting and boiling point.

No, magnesium ions are more reactive than hydrogen ions, so the Mg ions are more keen to stay as an ion, thus the hydrogen ions are reduced to hydrogen and then form hydrogen molecule.

Reply 136

bullster

are nanoparticles bigger or smaller than normal particles?

Reply 137

Meegan543210

I think grade boundaries will be 51-53 for an a* considering how this paper was set out nicely with no really tricky questions like the c1 paper last year with a grade boundary of 50 for an a*

Reply 138

Ben34bow

How did everyone get 200kg for the 6 mark question? I got 250kg - I did 500 + 200 + 50 = 750, and then divided it by 3. I know I will probably get some marks for it, but I just wondered what everyone else did. :confused:

Reply 139

Meegan543210

Original post by Katwamba01

That reminds me, there was a question after when it asks you after what type of bond is water. It was 'Why doesn't water conduct electricity?'
My answer is: Because water has weak intermolecular forces, but have a strong covalent bond as the electrons are shared therefore the atoms have no charges and so water cannot conduct electricity. (Which I don't know if it's correct)

Correct answer:
Water has a simple molecular structure which doesn't conduct electricity. This is because they do not have any free electrons or an overall electric charge as the covalent bond shares electrons between them

it said PURE water didn't it? And it doesn't have ions in it anyway... So I don't think you have to write about simple molecular substances it was one mark