WWW.SOLUTIONFANS.COM - MASTER OF ALL EXAM RUNS

Home
Stories
News
Edu
2017 chemistry OBJ/THEORY - solutionfans.com    

  • 2017 chemistry OBJ/THEORY - solutionfans.com
  • Share
    Tweet
    Whatsapp
    Mail

    CHEMISTRY OBJ.
    1DCDBCBDBCA
    11DBAADCDBCB
    21DBCBCCDBAD
    31BACBACBCCD
    41BDACABDABD

     

    1ai)
    an acid base indicator is a weak acid
    or weak base that exhibits a colour
    change as the concentration of
    hydrogen (H^+) or hydroxide (H^-)
    ions changes in an aqueous solution

    1aii)
    methyl-orange
    1b)
    i)oxidizing agent
    ii)mixed anhydride

    1c)
    enthalpy of combustion is the heat
    evolved when one mole of a
    substance is completely burns in
    oxygen gas under standard conditions

    1cii)
    enthapy of combustion is always
    negetive since it involvs a rise in
    temperature and heat of reactants is
    greater than the heat of products

    1d)
    primary cell is a cell that cannot be re
    charged while secondary cell is a cell
    that can be recharged

    1dii)
    primary cell — daniell cell
    secondary cell — lead accumulator

    1e)
    mole is the unit of measurement in
    the International System of Units (SI)
    for amount of substance. The unit is
    defined as the amount of a chemical
    substance which contains as many
    representative particles, e.g., atoms,
    molecules, ions, electrons, or photons,
    as there are atoms in 12 grams of
    carbon-12 (12C), the isotope of
    carbon with relative atomic mass
    1f)
    n= V=40cm^3
    c= 0.40moldm^3
    n=cv/1000
    0.40*40/1000 = 0.016mol

    2a)
    i)periodic law states that properties of
    elements are the periodic function of
    their atomic number
    ii)periodic property of element is the
    variation of the properties of element
    in a regular pattern both down the
    group and acrose the period

    2aii)
    i)ionization energy
    ii)electron affinity
    iii)electropositivity

    2aiii)
    ionization energy increase from left to
    right acrose a period because the
    nuclear charge increase progressively
    while the screening effect remain
    constant
    -atomic reduis decreases from left to
    right acrose the period because
    nuclear charge effect out weighs
    screening effect,which remains
    constant because the number of shell
    in a period is constant
    -electron affinity increase from left to
    right across a period because an
    additional electron will experience a
    greater repulsion than altraction from
    the positively charged nucleus

    2b)
    the relative atomic mass of an
    element is the mass of one atom of
    the element compared with the mass
    of an atom of the carbon -12 isotope
    whos mass is exactly 12

    2bci)
    isotopy

    2cii)
    the isotopes have difference number
    of neutron

    2ciii)
    R.A.M=(75/100*35)+(25/100*37)
    =2634.25

    2di)
    I CO2 by downward delivery
    II HCL by downward delivery
    III H2 by upward delivery
    2dii)
    I because it is denser than air
    II because it is denser than air
    3ai)
    Thermal cracking

    3aii)
    C4H8
    3aiii)
    (I) H H. H
    | | |
    H-C-C-C=C
    | | | |
    H H H H
    and
    (II) H H
    | |
    H-C-C=C-C-H
    | | | |
    H H H H
    3aiv)
    I-normal butene
    II -But-2-ene
    Ni
    3av)
    C4H8 +H2 ——-> C4H10
    250c

    3b)
    method
    – rub the fat on a blank white paper
    – pour Sudan (III) dye over the paper
    -wash the paper under tap
    Observation
    – rubbing the fat on the paper
    produces a translucent color
    -pouring sudan (III) will stain the
    blot red
    Conclusion
    – fat is present because sudan (III)
    can stain fat red

    5ai) worm the unknown substance
    with concentrated H2SO4 in a test
    tube. if trioxonitrate(v) ion’s are/is
    present, some trioxonitrate(v) acid will
    be condensed as oily drops on the
    upper part of the tube. On further
    heating, the acid decomposes yielding
    brown fums of NO2 gas.
    5iia) Sodium chloride is used for
    br /> =preserving food
    =glazing pottery
    5iib) Sodium trioxocarbonate(iv) is
    used for br /> =standardizing acids in the laboratory
    =the manufacture of glass

    [5bi)
    C(s) + O2(g) =====> Co2(g)
    Co2(g) + C(s) =====> 2Co(g)
    Fe2O3(s) + 3Co(g) =====> 2Fe(l) +
    3Co2(g)
    The limestone present decomposes as
    follows br /> CaCo3(s) =====> CaO(s) + Co2(g)
    Which is available to remove silicon
    (iv) oxide impurity
    SiO2(s) + CaO(s) =====> CaSiO3(s)

    5bii) Faraday’s first law of electrolysis
    states that, the mass (m) of an
    element discharged during an
    electrolysis is directly proportional to
    the quantity of electricity (Q) passing
    through it.

     264 total views,  1 views today



    If you like this story, please share it on Facebook, Twitter, Google+, Pinterest ETC.
    also don't forget to leave a Reply, we would very MUCH appreciate Your Comments On This Post Below. Thanks!
    Master Solution April 18, 2017 Categories: WAEC 1149


    Related Posts In » WAEC
    Waec 2023 Office Practice Objective And Theory Questions And Answers
    Waec 2023 Fisheries Practical Questions And Answers
    Waec 2023 Fisheries Objective And Theory Questions And Answers
    Waec 2023 Book Keeping Objective And Theory Questions And Answers
    Waec 2023 Animal Husbandry Practical Questions And Answers
    Waec 2023 Animal Husbandry Objective And Theory Questions And Answers
    Waec 2023 Further Mathematics Objective And Theory Questions And Answers
    Waec 2023 Marketing Objective And Theory Questions And Answers
    Waec 2023 Tourism Objective And Theory Questions And Answers
    Waec 2023 Islamic Religious Studies Objective And Theory Questions And Answers
    Waec 2023 Christian Religious Studies Objective And Theory Questions And Answers
    Waec 2023 Financial Accounting Objective And Theory Questions And Answers
    Waec 2023 Computer Science Objective And Theory Questions And Answers
    » See More Posts in- WAEC
    Be The First To Add A Comment

    7 Comments

    1. Mercy says:
      April 18, 2017 at 4:55 pm

      Thank u Sir

      Reply
    2. Mic says:
      April 18, 2017 at 4:32 pm

      I love ur early answers,, keep t up boss

      Reply
    3. Ice says:
      April 18, 2017 at 4:29 pm

      Thanks a lot for today. it has come and gone successfully

      Reply
    4. CHRIS says:
      April 18, 2017 at 4:23 pm

      Today was like fun to us.. u remain no 1

      Reply
    5. Diamond says:
      April 18, 2017 at 4:12 pm

      Sir u remain the best

      Reply
    6. Skip says:
      April 18, 2017 at 4:05 pm

      A well done job.

      Reply
    7. Oge says:
      April 18, 2017 at 4:03 pm

      Thanks ,, today was fine,, thanks for making it for us

      Reply
    Leave a comment
    Click here to cancel reply.

     Disclaimer                
    Comments, Pictures and culled stories posted on this website will be given due credit and is not the fault of Solutionfans.com if they are given original credit from site culled from. If you have a complaint or a story, Please Send To Us Via [email protected]
    Top
    Forum
    Contact
    © 2018 Solutionfans.com
    © 2016 - solutionfans.com Inc