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National 5 Chemistry

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hey guys you have to add the double bond in for this question. this is because when you get the molecular formula you should be able to find the general formula by counting the number of the atoms in the molecules. (No.of Carbon atoms etc.) once you find this general formula you should be able to find what family of hydrocarbon that it belongs too. (Alkene or Alkane). This will then help you decide whether you should put in the double bond or not. Hope this helps :smile:

Awww damn it haha but thanks for the explanation :smile:

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Reply 561

Jay431

Original post by Aaaaa01

Yea. Was that insulator? The ion bridge thing

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Yeah it was ion bridge

Reply 562

Emmaj2000

Original post by Aaaaa01

Set up 2 apparatus and for each experiment use one brand and another bran for the other experiment. Then heat it and the carbon dioxide will pass through the delivery tube into the test tube with lime water in it. Check what test tube is cloudier and the cloudier one will hav more carbon dioxide since lime water turns carbon dioxide cloudy.

I talked about the limewater experiment. I also talked about using a ph indicator as the one with the most carbon dioxide will be the most acidic. I also mentioned about a titration and my teacher said I was on the right tracks

Reply 563

M3g4nxx

Original post by Jay431

Yeah it was ion bridge

I've always been taught to call it a salt bridge, do you think I'll lose any marks for calling it that instead of 'ion bridge'?

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Reply 564

Ethan100

I have a question... For the Heat energy question what was the heat energy they give you in KJ

And also

Why didn't they have a double bond in the shortened structural formula for that question...
I was just following what it put for me, Am I just supposed to look at it and put a double bond ? If I did it wouldn't replicate the structural formula they gave us

Reply 565

reveen

Hey guys for the battery question in paper 2. I wrote electrolyte. i am feeling pretty confident that this is the correct answer. what are your opinions?

Reply 566

Ethan100

For the Heat energy question there were two methods, method A and B. What did you pick and why ?

Reply 567

reveen

Original post by Ethan100

You should know that there is a double bond because the number of bonds carbon forms is four. But in the molecular formula there was not enough atoms to join with the molecule indicating that there is a double bond. If you look at a previous post i have explained it thoroughly

Reply 568

Abbyy1234

Original post by reveen

Isn't it compulsory to include double and triple bond signs into shortened structural formula?

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Reply 569

reveen

Original post by Ethan100

For the Heat energy question there were two methods, method A and B. What did you pick and why ?

i picked method A as in method B the mass of the spirit burner is reduced more as we have to wait until it is lit and then put under the copper can meaning that in method b more of the alcohol is used. Therefore method A is more accurate.

Reply 570

reveen

Original post by Abbyy1234

Isn't it compulsory to include double and triple bond signs into shortened structural formula?

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Yes it is depending on what hydrocarbon. :smile:

(edited 7 years ago)

Reply 571

Puppo

Original post by Ethan100

Pretty sure the heat released was 23

Reply 572

Ethan100

Original post by Abbyy1234

Isn't it compulsory to include double and triple bond signs into shortened structural formula?

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Thats what Im trying to say...
For example if it was the other way around if they said to write the short structural formula we would lose marks if we missed out the double bonds. I know the chemistry involved when writing the full structural formula so I was just copying what I was given. I understand why its a double bond though

Reply 573

Ethan100

Original post by reveen

Yeah that's what I did too, You are losing Mass even before the experiment has actually started which will result in inaccurate results...

Reply 574

M3g4nxx

Original post by reveen

Hey guys for the battery question in paper 2. I wrote electrolyte. i am feeling pretty confident that this is the correct answer. what are your opinions?

I put electrolyte too

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Reply 575

reveen

Original post by Ethan100

so then what are you confused about then if you knew it had a double bond?

Reply 576

Abbyy1234

Original post by Ethan100

It's so annoying though because all these little 1 mark answers are starting to add up and I'm freaking out now :/

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Reply 577

Ethan100

Original post by Puppo

Pretty sure the heat released was 23

Thanks

Reply 578

reveen

Original post by Ethan100

Thanks

was it 23 i am pretty sure u got the wrong answer

Reply 579

Ethan100

Original post by reveen

so then what are you confused about then if you knew it had a double bond?

I don't know,, Doing any questions from nature's chemistry I was never taught by anyone that when you are given a short structural formula that has an insufficient amount of bonds for a certain atom (In this case carbon) to draw a double bond.

Oh well its done now, Thanks Reveen :smile: