CHEMISTRY PAPER 1 Marking Scheme - 2017 MURANG'A MOCK EXAMINATION

Share via Whatsapp
  1.  
    1. Water  
    2. Oxygen  is only slightly soluble in water.
    3.  
      • Used in welding  and cutting metals (oxy-acelytene  flame.
      • Used in Hospitals to ais patients with respiratory problems.
      • Metal extraction (To turn ore to oxide:
      • For fuels eg To burn   hydrogen to provide energy for space rockets.
  2.  
    p1 ans 2
  3.  
    1. Fermentation 
    2. Ethane is non - polar hence does not interact with polar water molecules unlike  ethanol which is polar.
  4.  
    1. -1e  
    2. N 50 =1.5625 
      50   32
      Any other method.
    3. Testing absorption of phosphorous from the fertilizer use radio active phosphorus - 31
  5.  
    1. Carbon  (IV)  Oxide and carbon (ii) oxide
    2. Carbon (IV) oxide
      • Fizzy drinks 
      • Fire extinguisher
      • Freezing material
        carbon ( II)  oxide.
      • As fuel
      • In meta extraction
  6.  
    1. 0.5 x (32 x 60) + 10
      0.5 x 1930 = 965 C 
      0.44  965C   88 X 965    =  193 000C
      88g                0.44
      Charge of X  =
      1930 
      965
      =  + 2
    2. P(OH)2
  1.  
    1.  
      1. r – ethanol 
      2. S  - chloro ethane  
    2. T – Dehydration 
  2. 60 cm3 =  50 sec
    80cm3  
    (80 x 50/60)=662/3 seconds
  3.  
    1. Salt Y -1 .At 50O c  only 82g of the 120g salt dissolves.
    2. 120 – 82
      = 38g
  4.  
    1. Moisture of water and oxygen/air
    2.  
      • Tin coating is non –toxic
      • Tin  coating is unreactive
      • Does not corrode easily
  5.  
    1. Add the colourless liquid to anhydrous copper (II) sulphate which  colour changes from white to blue
      OR Anhydrous  cobalt (II)  Chloride which colour changes from blue to pink. ( Any correct)
    2. Determine its refractive index 
      Determine its density which is 1 g/cm3
      Determine its boiling point as 100o C or freezing point as Oo C
  6.  
    1. Copper pyrite  (CUFeS2 ) 
    2. CUFeS2 (s)  +  Fe4O2 (g) → CU5 (s) +  2FeO (s) + 3SO3 (g)        
    3. Pollute environment due to SO2 gas which causes Acidic rain and can lead to leaching of soil/corrosion of house roof tops  .
    4.  
      • Making cooking 1 utensils
      • Electrical wires.
      • Making roofing sheets
      • coms and ornaments
      • making  alloys
  7.  
    1. Ca and Mg2 +  
    2. When hardwater is passed through the resin, magnesium 1 or calcium are retained in the resin.
  8.  
    1. staff  bridge 
    2. Fce  =  ER−E2  =  + 0.80 −(−0.13 ) 
      = 0.93V                                                  
  1. Conisation energy is the energy required to remove an electron from an atom in gases state while electron affinity is the energy released when an atom in gaseous state gains an electron. ½
  2. CuCO3  =    (64/124 X 100)=  51.61% copper  by mass     
  3. Alkaline earth metals 

  4.  
    1. Magnesium metal conducts due to presence of delocalized elections 
    2. Molten magnesium chloride conducts since it contains free ions. 
  1.  
    1. X – Base ions
    2. R
    3. T
  2.  
    1. allotrope – Two  or more forms of the same physical state of an element existing under standard conditions.
    2. Graphite atoms are bounded by covalent bonds to form layers which are held by weak van –derwaals forces making layers slides easily over each other. In Diamond there are only  covalent bonds.
  3.  
    1. 100 – 25 = 75 cm3
    2. CXHy + O2 +  H2O
      15cm3  75cm3; 45 = 1: 5: 3 
      Hence  CXH+ 50z → 3CO2 + 4H2 O
  4.  
    1. Aluminium has more  delocalized electrons than sodium making it  have strong metallic bonds hence higher melting point.
    2. Chlorine molecule is smaller compared to that of sulphur. Thus the van-der-waats forces in chlorine are weaker
  5.  
    1. anhydrons calcium chloride 
    2. Cooper (II) Oxide turns from Black to brown  
    3. Hydrogen  gas reduces copper (II)  oxide to copper metal which is brown.  
  1.  
    1. NaCl (s) + H2 SO4 (aq) → NaHSO4 (s)   + HCl (g)    
    2.  
      • React HCl  gas with iron to form iron (II)Chloride and hydrogen gas
      • React HCl gas with ammonia gas to form white fumes of ammonium chloride .
    3.  
      • Used in large scale  manufacture of HCL acid
      • Used in manufacture of polymers such as PVC
  2. The Red litmus paper remains red. This is because dry chlorine  gas does not bleach.
  3. By adding aqueous sodium chloride to separate solution  of the ions. In case of lead ions (Pb2) ions
    White precipitates will be observed while no precipitate form in case of calcium ions.
  4.  
    1. Phenol / phenopthalein indicator 1
    2. Acid                      Base                  Neutral
      Lemon juice         wood ash      Sodium chloride   
  1. RFM Ca(NO3 )2  = 40 + 28 + 96 = 164
    Thus 
    164  =  1 mole
    8.2 →      ?                8.2 X 1/164 = 0.05 mole
Join our whatsapp group for latest updates

Download CHEMISTRY PAPER 1 Marking Scheme - 2017 MURANG'A MOCK EXAMINATION.


Tap Here to Download for 50/-




Why download?

  • ✔ To read offline at any time.
  • ✔ To Print at your convenience
  • ✔ Share Easily with Friends / Students


Get on WhatsApp Download as PDF
.
Subscribe now

access all the content at an affordable rate
or
Buy any individual paper or notes as a pdf via MPESA
and get it sent to you via WhatsApp

 

What does our community say about us?

Join our community on:

  • easyelimu app
  • Telegram
  • facebook page
  • twitter page
  • Pinterest