Turn on thread page Beta
    • Thread Starter
    Offline

    15
    ReputationRep:
    Q1. What effect does the temperature have on a reaction between an acid and a salt and why?

    Temperature increases the kinetic energy & speed of the particles, so they collide more frequently and energetically - thus there is more of a chance of them overcoming activation energy and react, so faster rate of reaction. I think

    What are the three things you need to do for a successful industrial process depending on enzymes?
    Offline

    0
    ReputationRep:
    does anyone know where to get chem papers forr ocr from?! please!!
    Offline

    0
    ReputationRep:
    Answer to q1: the higher the temperature, the faster the reaction rate, for 2 reasons. Firstly, the reacatnt particles have more energy so they move around quicker, making collisons more likely and more frequent: there are more collisons per unit time. Also, as the reactants have more energy, they are more likely to collide with sufficient nergy (the activation energy), thereby allowing a reaction to occur.

    Question: During the purification of copper, one of the impurities which falls to the bottom is the metal platinum. Why does this not travel to the cathode and be discharged along with the copper ions?
    Also, zinc, another impurity, goes into the solution. Why does this also not bond with the cathode?
    Offline

    0
    ReputationRep:
    What are the three things you need to do for a successful industrial process depending on enzymes?
    Maintain the optimum temperature and pH level for the enzymes to work in. I cant think of a third thing.

    What conditions are needed for polymerisation to occur?
    Offline

    0
    ReputationRep:
    oops. Oh well here's the answer to excalibur's question:
    1. right pH, so enzymes not denatured or dormant
    2. right temperature (for same reason)
    3. right pressure? or a large enzyme surface area, e.g. pellets, powder or gauze? or a large surface area of reactants for enzyme to work on?

    Now can someone please answer my question(s):
    During the purification of copper, one of the impurities which falls to the bottom is the metal platinum. Why does this not travel to the cathode and be discharged along with the copper ions?
    Also, zinc, another impurity, goes into the solution. Why does this also not bond with the cathode?
    Offline

    1
    ReputationRep:
    No idea on that one i doubt we need to know.

    Q. what is the equation for moles of a solute?
    Offline

    14
    ReputationRep:
    (Original post by excellent_em)

    During the purification of copper, one of the impurities which falls to the bottom is the metal platinum. Why does this not travel to the cathode and be discharged along with the copper ions?
    Also, zinc, another impurity, goes into the solution. Why does this also not bond with the cathode?
    Educated guess but I'll edit if im wrong, could it be because the impurities have the same charge as the cathode, and only opposites attract
    Offline

    0
    ReputationRep:
    (Original post by FireDeuce)
    Educated guess but I'll edit if im wrong, could it be because the impurities have the same charge as the cathode, and only opposites attract
    But then what's stopping it from heading to the anode?

    Anyway, have a crack at this:

    Find the mass of MgO produced when Mg is burned with 1.7 Litres of Oxygen.
    Offline

    0
    ReputationRep:
    (Original post by Excalibur)
    Yes you're demented :p: Just kidding!
    OI....thanx a lot 4 that!!!! hehehe.

    as 4 ur Q excellent_em...basically

    metals that are lower in the electrochemical series to copper like platinum and silver do not go into solution as ions and fall to the bottom. since there are no ions.....they dont need to discharge!!!!

    metals higher in the series, like zinc...they go into solution but do not discharge at the cathode caus their concentration is relatively low??? i think.... but when the concentration does increase the conc. of copper ions will fall.

    am i rite...sorta?...can u please tell us the ans 4 this....its a gud question.

    roweski....wat do u mean 'moles of a solute'?...i dont rely understand what the Q is.
    • Thread Starter
    Offline

    15
    ReputationRep:
    The zinc/platinum question: metals that are more reactive tend to want to stay in solution and metals that are less reactive tend to want to get electrons to become atoms. I think
    Offline

    0
    ReputationRep:
    Find the mass of MgO produced when Mg is burned with 1.7 Litres of Oxygen
    1.7 litres= 1.7 dm (cubed).

    1 mole of gas equals 24 dm(cubed) therefore moles of oxygen = 1.7/24.

    =0.071 moles of O. Mass of O equal 0.071 mutliplied by 16= 1.13grammes.
    Then look at the equation 2Mg + O2 = 2MgO.
    32 grammes of O will give 40 grammes of MgO.
    therefore 1 gram of O gives 40/32 MgO
    so 1.13 grammes of O gives 40/32 multiplied by 1.13 multiplied by 2(account for moles) = 2.825 grammes

    So 2.825 grammes of MgO produced.

    Is that right? Let me know where i went wrong if i am. That was a long q is it a past q?

    Question: During the purification of copper, one of the impurities which falls to the bottom is the metal platinum. Why does this not travel to the cathode and be discharged along with the copper ions?
    Also, zinc, another impurity, goes into the solution. Why does this also not bond with the cathode?
    I thought it was because the solution used is copper sulphate so only Copper will dissolve in it to form ions. The other metals e.g. platinum and zinc dnt form ions because they dnt dissolve and so dnt get attracted to the cathode.
    Offline

    0
    ReputationRep:
    ive got ocr chemistry tomorrow, can somebody tell me were to get past papers and mark schemes?
    Offline

    0
    ReputationRep:
    i duno....i presume u've tried the OCR website? didnt your teacher giv u any?
    *OMG 100+ posts*
    Offline

    0
    ReputationRep:
    Ok im stuck on this question in a test:

    The equation for the reaction between iron and dilute sulphuric acid is

    Fe + H2SO4 --> FeSO4 + h2

    in the reaction 0.56g of iron reacted with dilute sulphuric acid, calculate the mass of iron [II] sulphate (FeSO4) formed.

    H=1 o=16 s=32 fe 56


    Help please lol
    Offline

    2
    ReputationRep:
    Ar Fe = 56g = 1 mole
    So 0.56g = 0.01 mole Fe

    From the equation we can see that:
    1 mole Fe --> 1 mole FeSO4
    0.1mole Fe --> 0.01 mole FeSO4

    Mr FeSO4 = 56 + 32 + (4 x 16) = 152g = 1 mole
    So 0.1 mole of FeSO4 = 152 x 0.01 = 1.52g FeSO4
    Offline

    0
    ReputationRep:
    1 mole of Fe and 1 mole of FeSO4....so no problems there.

    0.56/56 =0.01 moles yeh?

    0.01 x (56+ 32+ (4x16)

    cant be bothered to calculate any further.....

    EDIT: lol xemmajanex....same tym eh.
    By the way....ive just realised **** is actually calcium silicate! lol. thanx excalibur for some clarification.
    • Thread Starter
    Offline

    15
    ReputationRep:
    (Original post by InterAdriano)
    Ok im stuck on this question in a test:

    The equation for the reaction between iron and dilute sulphuric acid is

    Fe + H2SO4 --> FeSO4 + h2

    in the reaction 0.56g of iron reacted with dilute sulphuric acid, calculate the mass of iron [II] sulphate (FeSO4) formed.

    H=1 o=16 s=32 fe 56


    Help please lol
    Mass of Fe = 0.56g
    Ar of Fe = 56
    Moles of Fe = 0.56/56 = 0.01

    Mass of FeSO4 = ?
    Mr of FeSO4 = 152
    Moles = 0.01 (same as the Fe because they both have same number of moles)
    Mass = moles x Mr = 0.01 x 152 = 1.52g.

    Is that right?
    Offline

    2
    ReputationRep:
    0.56g is 0.01 moles, not 0.1 moles! Silly me :p: Excalibur's right though...
    • Thread Starter
    Offline

    15
    ReputationRep:
    Hehe we all posted at the same time! :p:

    OK, I have a query: in the specification it says (for enzymes in industry): "stabilise the organism to keep it functioning for a long period". What does this mean?
    Offline

    0
    ReputationRep:
    erm....what organism? i hope they are not referring to enzymes as organisms.
    how exactly are enzymes used anyway?....i know the uses but not any further than that....like washing powders etc.

    btw....exaclibur ...dyu do Edexcel science or AQA/OCR?
 
 
 

University open days

  • University of East Anglia
    UEA Mini Open Day Undergraduate
    Fri, 23 Nov '18
  • Norwich University of the Arts
    Undergraduate Open Days Undergraduate
    Fri, 23 Nov '18
  • Edge Hill University
    All Faculties Undergraduate
    Sat, 24 Nov '18
Poll
Black Friday: Yay or Nay?
Useful resources

Study tools

Rosette

Essay expert

Learn to write like a pro with our ultimate essay guide.

Thinking about uni already?

Thinking about uni already?

See where you can apply with our uni match tool

Student chat

Ask a question

Chat to other GCSE students and get your study questions answered.

Creating

Make study resources

Create all the resources you need to get the grades.

Planner

Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

Papers

Find past papers

100s of GCSE past papers for all your subjects at your fingertips.

Help out other students

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.