AQA GCSE Chemistry Unit 2 24 May 2012

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Reply 100

killmenow

Original post by osama2

32 for an A maybe 33 :frown:

Oh dear.. Well im screwed then :frown:

Reply 101

Aidanb90

What did anyone get for the mass of the 1dm of gas in the syringe? 53.something - 51. something,something

The answer 1.57 g, or something like that?

And reasons for experimental error?

The answer, Weighing error (using balance incorrectly)
and some of the gas could have escaped from the tube.

What did anyone else get?

Reply 102

osama2

how were u meant to work out the weight of the gas. did u have to take away the tow number? take away 53. something and 51. something?

Reply 103

daniya12

Original post by Aidanb90

yes i got 1.57g, as for the experimental error,
is aid that they may have measured the mass of gas in the syringe worng beofre and after.
and that they may not have measured 1dm of gas, so incorrect measure of volume.

i agree with some gas could have escaped, think that would be pn the mark scheme

Reply 104

Aidanb90

Original post by osama2

how were u meant to work out the weight of the gas. did u have to take away the tow number? take away 53. something and 51. something?

Yes i did the same

Reply 105

daniya12

Original post by osama2

how were u meant to work out the weight of the gas. did u have to take away the tow number? take away 53. something and 51. something?

yeh thats how you were supposed to do it

Reply 106

Princess008

Original post by daniya12

yeh thats how you were supposed to do it

i thougth you had to add them as it said the gas. so the total gas so you add gas before and after gas to give you the total gas?

Reply 107

killmenow

i found it sooo hard, and so did everyone i asked. really hope the grade boundaries are not high :s-smilie:

Reply 108

xoxlovelifexox

what are everyone's guesses for grade boundaries and full UMS etc.? just nice to hear some opinions :smile:

Reply 109

daniya12

Original post by Princess008

i thougth you had to add them as it said the gas. so the total gas so you add gas before and after gas to give you the total gas?

it asked for the gas lost, so you look at the difference

Reply 110

osama2

lets work on tge mark scheme then we can see what everyone think they got. so then we can predict them. first lets complete the marksheme.

Reply 111

Chlomc

How would the results be made more percise? (1)
Giving data to 3dp rather than 2dp
Calculate the mean average for these results? (2)
Give to examples of experimental errors that could have been made? (2)
Why is it important to repeat each experiment? (1)
To get more reliable accurate results
Diagram you had to complete of N and Cl covanetly bonded together
What kind of bonding is this? (1)
Covalent bonding
Diamond are very hard, why is this. Include information on the bonding and structure of diamonds? (3)
Giant covalent bond
Particles tight together
Strong intermolecular forces
What does a precipitate recation mean?
A solid is produced
How would you get the (solid product - cant remember the name :L) seperate?
evaporation
Filtration (1)
What happens in the seperator?
Why is stage 4 needed?
If heat energy applied to this rection decreases then the amount of amonia made increases, why is this? (1)
Because its an exothermic reaction
The manu factorers increase the pressure to (high number) why dont they go over this? (1)
What is the percentage of amonia made from the possible amount? (1)
15%
Why does it not matter that its a low percentage made?
Because the unreacted nitrogen and hydrogen are recyled to go through the process again.
Explain the structure and bonding of gold? (3)
Metalic bonding
Overlapping outter shell of electrons
Delocalised electrons
Electrostatic forces
Tightly packed together particles
Why is gold a good conducture of electricity? (2)
Delocalised eclectrons
Electrons from outter shells have pathways through whole metal structure
Iron surface corrodes when exposed to air, this reduces its ability to conduct, explain why? (2)
If there is 20m of nitrogen how much hydrogen would you need?
how much ammonia could you make with 2g of nitrogen?
Why when pressure is increase does the amount of ammonia increase?
Complete this equation Ca = Ca2+ + ?
Ca = Ca2++ 2e-
Why is this described as oxidation?
Electrons are lost
What ion makes soluton acidic?
Which ion make soltuion alkaine?
Why do the chloride ions go to the positive electorde

This is and updated verision of the the questions i can remember, some of the answers im not sure about allong with how many marks awarded but if anyone thinks they know please post an updated version
Thanks!

(edited 11 years ago)

Reply 112

daniya12

1)
why do chloride ions go to positive elctrode?
- they are negatively charged (1)
what ions make solution alkaline?
-hydroxide ions/ OH- (2)
mean mass?
- ignore anomaly, so you get45.3333 (2)
what ions make it a ph of 1?
- hydrogen ions H+ (1)

i think thats all of question 1?, please correct me if im worng, add changes etc etc etc

Reply 113

Princess008

1) hydrocholric acid
2)why ions move -
opposite charget attract
3) ticking hydrogen
hydrogen is less reactive
4) what is the x alkaine
5) atomic mass
6)drawing dot and cross diagram
7) what is the bonding called
covalent bond
8) what is added to something
chlorine or chloride

Reply 114

Chlomc

why do chloride ions go to positive elctrode?
- they are negatively charged (1)
what ions make solution alkaline?
-hydroxide ions/ OH- (2)
Hydrogen is made at positive elctrode, why? (1)
-tick less reactive
mean mass?
- ignore anomaly, so you get45.3333 (2)
2 types of experimental errors that could be made (2)
- dont know the answers :s
what ions make it a ph of 1?
- hydrogen ions H+

added another question which was here :smile:

i thinks that number one

(edited 11 years ago)

Reply 115