F321 27th May 2016

Reply 40

UnknownAnon

9

Original post by KaylaB

Then don't you divide by 2 because it was an Nitrogen molecule which is N2 and it asked for atoms?

That's what I did. Divided by two first. Then divided by avagadros.

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Reply 41

bigzman123

1

Original post by Rust Cohle

What was the reaction?

It was disproportionation, mg was both oxidised and reduced

Reply 42

Rust Cohle

6

How many marks were there for the Nitrigen dot cross

Reply 43

Dolphinflips

11

Was wondering what was everyone's views on the exam, because I'm trying to work out whether grade boundaries will be high or low? I personally was disappointed in the exam, found it harder then previous years and a lot more sneaky, so kind of feel like I want to cry. Also what did everyone get for the empirical formula for the acid?? (it was one of the first questions on the second page)

Reply 44

SamH213

1

Was it chlorine water and bromine water or iodine water and bromine water?

Reply 45

SamH213

1

Original post by Dolphinflips

Was wondering what was everyone's views on the exam, because I'm trying to work out whether grade boundaries will be high or low? I personally was disappointed in the exam, found it harder then previous years and a lot more sneaky, so kind of feel like I want to cry. Also what did everyone get for the empirical formula for the acid?? (it was one of the first questions on the second page)

It was nitric acid hno3, i thought it was pretty straightforward if im honest, probably the usual stupid mistakes though.

(edited 7 years ago)

Reply 46

UnknownAnon

9

Original post by Dolphinflips

Was wondering what was everyone's views on the exam, because I'm trying to work out whether grade boundaries will be high or low? I personally was disappointed in the exam, found it harder then previous years and a lot more sneaky, so kind of feel like I want to cry. Also what did everyone get for the empirical formula for the acid?? (it was one of the first questions on the second page)

I got HNO3 for the acid. And I have a feeling it will be higher. From what I've heard, most people found it easy and everyone who did it is retakers. Btw did anyone else write sulphur fluoride instead of hexaflouride? :frown:

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Reply 47

GillyTheGhillie

10

Someone remind me of the questions not listed here cos I forgot some.

1. Seriously if you dont know protons neutrons and electrons relative mass charge and position, theres no hope.

S: Spherical
P: Dumbell

Relative energies I was unsure

Nitrogen dotcross had 3 crosses and 3 dots shared between the and one lone pair each.

No of moles of nitrogen atoms was 1.7 x10^-3

Remind me of others for q1

2. Remind me of q2

3. Ditto

4. Ditto

5. Ditto

6. Ditto

Unsure what question numbers:

Halide test question minimum no was 2 and it was bromine water plus the chloride and iodide, layer colour plus chloride was orange, plus iodide was purple

Mass of aluminium sulfate formed was 0.120 grams

Volume of gas produced was 1200 cm^3

Reason sodium has lower mp was because it has a higher ionic radius and lower charge.

Vdw comes about because of uneven electron diatribition causing instantaneous dipoles that induce dipoles in other atoms that causes them to be electrostatically attracted

Reason bromine has a higher bp was because it has more electrons so more likely to have uneven electron distribution.

Acid produced was Nitrous acid, HNO2

Calcium compound used to change soil pH would be hydroxide or oxide.

6Ca plus P4 goes to 2Ca3P2

Ionic structure was 3 Ca^2+ ions and 2 P^3- ions.

Oxygen was 2+ in oxygen difluoride.

2F2 + 2NaOH goes to F2O + 2NaF + H2O

Bond angle was 104.5°

Sulfur/Flourine compound was SF6, Sulfur Hexafluoride

Table question, Sodium has the lowest first ionisation, Silicon lowest forth, Neon lowest BP.

Remind me of qs and Ill give answers

(edited 7 years ago)

Reply 48

bigzman123

1

Original post by SamH213

Was it chlorine water and bromine water or iodine water and bromine water?

Bromine water

equation Br2 + 2 I- --> I2 and 2Br- forms forms violet solution in cyclohexane

Reply 49

SazahSauce

1

The acid was HNO2 because the equation wouldn't have balanced as HNO3

Reply 50

bigzman123

1

Original post by SazahSauce

The acid was HNO2 because the equation wouldn't have balanced as HNO3

yessss, molecular was h2No2O4 cos there were no other products

empeirical HNO02

Reply 51

GillyTheGhillie

10

Original post by bigzman123

yessss, molecular was h2No2O4 cos there were no other products

empeirical HNO02

No, it was HNO2, nitrous acid.

Reply 52

sqr00t

2

Original post by bigzman123

yup there were 5 moles in total so 1200

2 moles on left hand side though

Reply 53

MrKmas508

12

Original post by GillyTheGhillie

No, it was HNO2, nitrous acid.

That's what I got.

Reply 54

bigzman123

1

Original post by sqr00t

2 moles on left hand side though

yh divided first mol answer by 2 and times 5

Reply 55

GillyTheGhillie

10

Original post by sqr00t

2 moles on left hand side though

Yes, it would have been 2400 had he not taken that into account, the correct answer was 1200

Reply 56

SazahSauce

1

Original post by sqr00t

2 moles on left hand side though

There were two different gases on the right hand side, you had to divide moles by 2 to get 0.01 and multiply moles by 2 to get 0.04 so there was 0.05 moles of gas on the right hand side

Reply 57

Dolphinflips

11

Original post by SamH213

It was nitric acid hno3, i thought it was pretty straightforward if im honest, probably the usual stupid mistakes though.

I got nitrous acid, because I tried doing a balanced equation with nitric acid and it wouldn't work, just praying that the dumb mistakes aren't too many, I was really annoyed with the oxygen oxidation number and the naming of SF6