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    First of all, good luck to everyone sitting the exam on Monday! I hope your studying is going well!

    Now, I was wondering if someone could help me with redox reactions? Just the general idea of how you form one? I find them so very confusing I'll be forever grateful. Also, if anyone has any questions perhaps we can all help if they are posted here?

    Do you find Chemistry easy or hard? I find it super difficult. I was planning on taking it to Higher but I'm just so bad at it so I'm doing Higher Biology instead. Hopefully. If I pass my Nat5
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    Good luck to you too!

    I find it easy and so very boring. There's not many concepts to grasp at this level, so most of it just seems logical and common sense. I can't even bring myself to do the model papers, it's so uninteresting...

    Redox reactions are a combination of oxidation and reduction reactions. Remember that oxidation and reduction, in chemistry, refer to ELECTRONS. Oxidation = loss of electrons. Reduction = gain of electrons.

    An oxidation reaction could, for example, be:

    K ----> K+ + e-

    In oxidation reactions, remember that an ATOM is LOSING electrons to form an ION. The electron is always on the right-hand side.

    In this case potassium (K) only has one outer electron so it makes ions with a 1+ charge. Therefore, a potassium atom forms a potassium ion and ONE electron.

    If the atom has more than one outer electron then you need to show the number of electrons 'formed'/lost in front of the e- symbol. For example, calcium (atomic number 20) has 2 outer electrons so it loses 2.

    e.g. Ca ---> Ca2+ + 2e-

    Reduction follows the exact same 'rules' except an ION is GAINING electrons to become a NEUTRAL ATOM.

    K+ + e- ----> K

    In reduction equations the e- is always on the left. Again, remember to check the no. of electrons depending on the ion.

    Ca2+ + 2e- ----> Ca

    Redox reactions are easier than you think. You first need to identify the individual oxidation and reduction reactions, and put them together. Let's use Lithium and Iron as an example.

    Oxidation (losing):

    Li ----> Li+ + e-

    Reduction (gaining):

    Fe2+ + 2e- ----> Fe

    Redox:

    Li + Fe2+ ----> Li+ + Fe

    All you do for the Redox is combine the oxidation and reduction equations and eliminate the electrons. Note that you might need to balance the equation, i.e. 2 ions of an element would need to equate to 2 atoms of that element. In this example it's already balanced.

    You might be wondering why Lithium specifically loses the electrons and why Iron gains them. That's because Redox equations are always to do with batteries at Nat 5. Remember that electrons flow from the more reactive metal to the less reactive, so from lithium to iron, meaning lithium LOSES and iron GAINS.

    Hope this makes you understand better. I'm on my phone so I couldn't use superscripts to show charges :P
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    (Original post by Ecasx)
    Good luck to you too!

    I find it easy and so very boring. There's not many concepts to grasp at this level, so most of it just seems logical and common sense. I can't even bring myself to do the model papers, it's so uninteresting...

    Redox reactions are a combination of oxidation and reduction reactions. Remember that oxidation and reduction, in chemistry, refer to ELECTRONS. Oxidation = loss of electrons. Reduction = gain of electrons.

    An oxidation reaction could, for example, be:

    K+ + e-1 ----> K

    In oxidation reactions, remember that an ION is GAINING electrons to become a NEUTRAL ATOM. The electron is always on the left-hand side: the ion plus the electron ---> an atom.

    In this case potassium (K) only has one outer electron so it makes ions with a 1+ charge (by losing one electron). Therefore, a potassium ion plus ONE electron makes a potassium ion.

    If the ion has a charge greater than 1 then you need to show the number of electrons needed in front of the e- symbol.. For example, calcium (atomic number 20) has a 2+ charge so it needs 2 electrons.

    e.g. Ca2+ + 2e- ----> Ca

    Reduction follows the exact same 'rules' except an ATOM is LOSING electrons to become an ION.

    K ----> K+ + e

    You end up with electrons, so in reduction reactions the e- is always on the right. Again, remember to check the no. of electrons depending on the atom/ion:

    Ca ----> Ca2+ + 2e-

    Redox reactions are easier than you think. You first need to identify the individual oxidation and reduction reactions, and put them together. Let's use Lithium and Iron as an example.

    Oxidation (losing):

    Li ----> Li+ + e-

    Reduction (gaining):

    Fe2+ + 2e- ----> Fe

    Redox:

    Li + Fe2+ ----> Li+ + Fe

    All you do for the Redox is combine the oxidation and reduction equations and eliminate the electrons. Note that you might need to balance the equation, i.e. 2 ions of an element would need to equate to 2 atoms of that element. In this example it's already balanced.

    You might be wondering why Lithium specifically loses the electrons and why Iron gains them. That's because Redox equations are always to do with batteries at Nat 5. Remember that electrons flow from the more reactive metal to the less reactive, so from lithium to iron, meaning lithium LOSES and iron GAINS.

    Hope this makes you understand better. I'm on my phone so I couldn't use superscripts to show charges :P

    Thank you sooo much You made it sound pretty simple!

    I used to understand Chemistry and then I got a new teacher and she's the worst. She has her favourite students and if you are any one other than them, when you ask for help, she gets angry and really patronising. So I don't ask. My friend from another class and her teacher after school occasionally had to teach me Unit 3 of the course. But I do sort of understand the rest

    Thanks again!
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    (Original post by Ecasx)
    Good luck to you too!

    I find it easy and so very boring. There's not many concepts to grasp at this level, so most of it just seems logical and common sense. I can't even bring myself to do the model papers, it's so uninteresting...

    Redox reactions are a combination of oxidation and reduction reactions. Remember that oxidation and reduction, in chemistry, refer to ELECTRONS. Oxidation = loss of electrons. Reduction = gain of electrons.

    An oxidation reaction could, for example, be:

    K+ + e-1 ----> K

    In oxidation reactions, remember that an ION is GAINING electrons to become a NEUTRAL ATOM. The electron is always on the left-hand side: the ion plus the electron ---> an atom.

    In this case potassium (K) only has one outer electron so it makes ions with a 1+ charge (by losing one electron). Therefore, a potassium ion plus ONE electron makes a potassium atom.

    If the ion has a charge greater than 1 then you need to show the number of electrons needed in front of the e- symbol.. For example, calcium (atomic number 20) has a 2+ charge so it needs 2 electrons.

    e.g. Ca2+ + 2e- ----> Ca

    Reduction follows the exact same 'rules' except an ATOM is LOSING electrons to become an ION.

    K ----> K+ + e

    You end up with electrons, so in reduction reactions the e- is always on the right. Again, remember to check the no. of electrons depending on the atom/ion:

    Ca ----> Ca2+ + 2e-
    Wait what, have you not got these the wrong way round?? :confused: How is 'K+ + e-1 --> K' an example of oxidation?
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    (Original post by chopinfan)
    Wait what, have you not got these the wrong way round?? :confused: How is 'K+ + e-1 --> K' an example of oxidation?
    ****, you're right haha!

    My bad, switch them around!!!
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    (Original post by Ecasx)
    Good luck to you too!

    I find it easy and so very boring. There's not many concepts to grasp at this level, so most of it just seems logical and common sense. I can't even bring myself to do the model papers, it's so uninteresting...

    Redox reactions are a combination of oxidation and reduction reactions. Remember that oxidation and reduction, in chemistry, refer to ELECTRONS. Oxidation = loss of electrons. Reduction = gain of electrons.

    An oxidation reaction could, for example, be:

    K+ + e-1 ----> K

    In oxidation reactions, remember that an ION is GAINING electrons to become a NEUTRAL ATOM. The electron is always on the left-hand side: the ion plus the electron ---> an atom.

    In this case potassium (K) only has one outer electron so it makes ions with a 1+ charge (by losing one electron). Therefore, a potassium ion plus ONE electron makes a potassium atom.

    If the ion has a charge greater than 1 then you need to show the number of electrons needed in front of the e- symbol.. For example, calcium (atomic number 20) has a 2+ charge so it needs 2 electrons.

    e.g. Ca2+ + 2e- ----> Ca

    Reduction follows the exact same 'rules' except an ATOM is LOSING electrons to become an ION.

    K ----> K+ + e

    You end up with electrons, so in reduction reactions the e- is always on the right. Again, remember to check the no. of electrons depending on the atom/ion:

    Ca ----> Ca2+ + 2e-

    Redox reactions are easier than you think. You first need to identify the individual oxidation and reduction reactions, and put them together. Let's use Lithium and Iron as an example.

    Oxidation (losing):

    Li ----> Li+ + e-

    Reduction (gaining):

    Fe2+ + 2e- ----> Fe

    Redox:

    Li + Fe2+ ----> Li+ + Fe

    All you do for the Redox is combine the oxidation and reduction equations and eliminate the electrons. Note that you might need to balance the equation, i.e. 2 ions of an element would need to equate to 2 atoms of that element. In this example it's already balanced.

    You might be wondering why Lithium specifically loses the electrons and why Iron gains them. That's because Redox equations are always to do with batteries at Nat 5. Remember that electrons flow from the more reactive metal to the less reactive, so from lithium to iron, meaning lithium LOSES and iron GAINS.

    Hope this makes you understand better. I'm on my phone so I couldn't use superscripts to show charges :P
    As above, you are confusing oxidation and reduction in your examples. Also it would be incorrect to say that reduction is gain of electrons to form an atom from an ion as these are all examples of reduction:

    Na+ + e- --> Na. Ion to atom

    Cl + e- --> Cl- atom to ion

    Fe3+ + e- --> Fe2+ ion to ion

    The same applies to oxidation.




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    Fixed the post, don't wanna confuse.


    (Original post by Asklepios)
    As above, you are confusing oxidation and reduction in your examples. Also it would be incorrect to say that reduction is gain of electrons to form an atom from an ion as these are all examples of reduction:

    Na+ + e- --> Na. Ion to atom

    Cl + e- --> Cl- atom to ion

    Fe3+ + e- --> Fe2+ ion to ion

    The same applies to oxidation.




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    This is Nat 5 bro. We're only concerned with reduction/oxidation in terms of electrochemical cells which don't feature what you've pointed out, but I guess knowledge doesnt hurt.
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    (Original post by Ecasx)
    ****, you're right haha!

    My bad, switch them around!!!
    Haha yeah, good explanation btw :P Really need to start looking at some past papers etc tomorrow, we didn't even finish unit 3 in class properly so should probably spend some time on bbc bitesize as well.

    Good luck for the rest of your exams!! Is chemistry next up for you?
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    (Original post by chopinfan)
    Haha yeah, good explanation btw :P Really need to start looking at some past papers etc tomorrow, we didn't even finish unit 3 in class properly so should probably spend some time on bbc bitesize as well.

    Good luck for the rest of your exams!! Is chemistry next up for you?
    Thanks for pointing it out haha. What past papers are you going to use? I've got the Nat 5 model papers (scanned) as files, I can send you them if you want.

    Yeah, we didn't finish Unit 3 either, the course really is pretty big. Guess I'll have to hire a tutor HA HA.

    Chemistry's next! 2 down, 5 still to go :/ What's your next one, chem too?


    P.S. Appreciate the comment about my explanation. I wrote it on my phone while taking a ****.
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    (Original post by Ecasx)
    Thanks for pointing it out haha. What past papers are you going to use? I've got the Nat 5 model papers (scanned) as files, I can send you them if you want.

    Yeah, we didn't finish Unit 3 either, the course really is pretty big. Guess I'll have to hire a tutor HA HA.

    Chemistry's next! 2 down, 5 still to go :/ What's your next one, chem too?
    Em I was just going to use some old int 2 ones and that would be great if it's not too much trouble!

    It is actually and yeah So many free resources available online, I don't see why people can't just take some time to appreciate and understand them.

    Yup chemistry also and ditto with the 5 left. Got three exams including chemistry next week though so busy times ahead!
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    (Original post by chopinfan)
    Em I was just going to use some old int 2 ones and that would be great if it's not too much trouble!

    It is actually and yeah So many free resources available online, I don't see why people can't just take some time to appreciate and understand them.

    Yup chemistry also and ditto with the 5 left. Got three exams including chemistry next week though so busy times ahead!
    Send me your e-mail so I can send them! Teacher gave us it.

    Exactly.

    Best of luck!
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    (Original post by Ecasx)
    Send me your e-mail so I can send them! Teacher gave us it.

    Exactly.

    Best of luck!
    Could you possibly send them to me as well please.
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    (Original post by Ecasx)

    I wrote it on my phone while taking a ****.
    You are just charming.

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    Just wondering how garden is national 5 chemistry if you've done another science ? Not sure if I should take it or not.
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    (Original post by Ecasx)
    I find it easy and so very boring.
    Oxidation (losing):

    Li ----> Li+ + e-

    Reduction (gaining):

    Fe2+ + 2e- ----> Fe

    Redox:

    Li + Fe2+ ----> Li+ + Fe
    Is that right? You find it easy? Name:  1398473591971.jpg
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    (Original post by langlitz)
    Is that right? You find it easy? Name:  1398473591971.jpg
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    Actually, that redox equation is correct.

    National 5 is not a great challenge, as you will probably know.
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    (Original post by Ecasx)
    Actually, that redox equation is correct.

    National 5 is not a great challenge, as you will probably know.
    I beg to differ

    It should be 2Li + Fe2+ --> 2Li+ + Fe
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    (Original post by langlitz)
    I beg to differ

    It should be 2Li + Fe2+ --> 2Li+ + Fe
    Oh, because 2 electrons are needed => 2Li...

    I'm sorry. You're right. I did write that while taking a dump though, and I've yet to revise any part of chemistry since the January prelims.
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    Ok so I started studying chemistry today but this question's confused me. It's from Int 2, so maybe there's something we've not learnt (since Int 2 seems to delve more into biology; proteins, carbs, fats etc.) but I'm probably wrong. Could anyone help me on how to get to the answer here? The answer is C.
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    (Original post by Ecasx)
    Ok so I started studying chemistry today but this question's confused me. It's from Int 2, so maybe there's something we've not learnt (since Int 2 seems to delve more into biology; proteins, carbs, fats etc.) but I'm probably wrong. Could anyone help me on how to get to the answer here? The answer is C.
    I got that one wrong as well but i think I understand it now. The -COOH's are what you find on a carboxylic acid. So to neutralise these bits we need to add an -OH (as happens when the hydroxyl of an alcohol joins on to a carboxylic acid to produce an ester). For each -COOH we need 1 -OH. Using valencies we know that there is one hydroxide in sodium hydroxide so therefore we need 3 of these to neutralise the acid. I'm not very good at chemistry so if I'm completely wrong please correct me.
 
 
 

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