JAMB - Chemistry (2020)

• 1

  The electronic configuration of an element is 1S\(^2\) 2S\(^2\) 2P\(^6\) 3S\(^2\) 3P\(^3\). How many unpaired electrons are there in the element?

  Vastaus

  (C)

  3
• 2

  Which of the following can be obtained by fractional distillation? 

  Vastaus

  (A)

  Nitrogen from liquid air
• 3

  Duralumin consists of aluminum, copper?

  Vastaus

  (D)

  Manganese and Magnesium
• 4

  An example of a polysaccharide is?

  Vastaus

  (D)

  Starch
• 5

  8g of CH\(_4\) occupies 11.2 at S.T.P. What volume would 22g of CH\(_3\)CH\(_2\)CH\(_3\) occupy under the same condition?

  Vastaus

  (B)

  11.2dm\(^3\)
• 6

  The best treatment for a student who accidentally poured conc tetraoxosulphate(vi) on his skin in the laboratory is to wash his skin with?

  Vastaus

  (A)

  with cool running water
• 7

  

  Which of the gas laws does this graph illustrate?

  Vastaus

  (B)

  Charles
• 8

  What are the possible oxidation numbers of an element if its atomic number is 17?

  Vastaus

  (A)

  -1 and 7
• 9

  What process would coal undergo to give coal gas, coal tar, ammoniacal liquor and coke?

  Vastaus

  (B)

  Destructive distillation
• 10

  Liquid black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the ?

  Vastaus

  (C)

  Alkali
• 11

  When water drops are added to calcium carbide in a container and the gas produced is passed through a jet and lighted, the resultant flame is called an?

  Vastaus

  (C)

  Oxyacetylene flame
• 12

  Which of the following substances is a mixture?

  Vastaus

  (B)

  Seawater
• 13

  If the quantity of oxygen occupying 2.76L container at a pressure of 0.825 atm and 300k is reduced by one-half, what is the pressure exerted by the remaining gas?

  Vastaus

  (A)

  1.650atm
• 14

  Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is noble gas? 

  Vastaus

  (B)

  Q
• 15

  The products of the thermal decomposition of ammonium trioxonitrate(v) are?

  Vastaus

  (A)

  Nitrogen (I) Oxide and Water
• 16

  How many valence electrons are contained in the element \(^{31}_{15}P\)?

  Vastaus

  (A)

  3
• 17

  The number of molecules of Carbon(iv)Oxide produced when 10.0g of CaCO\(_3\) is treated with 0.2dm\(^3\) of 1 Mole of HCL in the equation

  CaCO\(_3\) + 2HCL ⇒ CaCl\(_2\)  + H\(_2\) O + CO\(_2\)  , is?

  Vastaus

  (C)

  6.02 X 10\(^{22}\)
• 18

  The volume occupied by 1.58g of a gas at S.T.P is 500cm\(^3\). What is the relative molecular mass of the gas?  [ G.M.V at S.T.P = 22.4dm\(^{3}\) ]

  Vastaus

  (D)

  71
• 19

  Which of the following gases will rekindle a brightly splint?

  Vastaus

  (C)

  N\(_2\)O
• 20

  The shape of ammonia molecule is?

  Vastaus

  (A)

  Trigonal planar
• 21

  A few drop of conc HCL are added to about 10cm\(^3\) of a solution of PH 3.4. The PH of the resulting mixture is?

  Vastaus

  (A)

  less than 3.4
• 22

  Chromatography is used to separate components of mixture which differ in their rates of ?

  Vastaus

  (B)

  migration
• 23

  Deliquescent substances are also?

  Vastaus

  (C)

  hygroscopic
• 24

  Helium is used in observation of ballons because it is?

  Vastaus

  (B)

  light and non-combustible
• 25

  32g of anhydrous copper(ii)tetraoxosulphate(vi) dissolved in 1dm\(^3\) of water generated 13.0kj of heat. The heat solution is?

  Vastaus

  (B)

  65.0kj/mol
• 26

  A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

  [ M = 27, Cl = 35.5]

  Vastaus

  (C)

  MCl\(_3\)
• 27

  What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

  Vastaus

  (B)

  48,250 C
• 28

  Which of the following types of bonding does not involve the formation of new substances?

  Vastaus

  (A)

  Metallic
• 29

  An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?

  Vastaus

  (A)

  Alkene
• 30

  The substance often used for vulcanization of rubber is?

  Vastaus

  (C)

  Sulphur
• 31

  The chlorinated alkane often used industrially to remove grease is?

  Vastaus

  (A)

  Tetrachloromethane
• 32

  What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?

  Vastaus

  (D)

  72.0g
• 33

  Proteins in acid solution undergo?

  Vastaus

  (C)

  Hydrolysis
• 34

  The general formula for the Alkanals is?

  Vastaus

  (B)

  RCHO
• 35

  When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes?

  Vastaus

  (B)

  Negatively charged