Chapter 1 Basic Concepts MCQs with Answers

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Mcqs for entry test preparation for pre medical and pre engineering form chemistry book 1 chapter 1. Also helpful for all boards of intermediate and secondary education Pakistan.
 
CHEMISTRY  CH#1 (VOL-1)     BASIC CONCEPTS

  1. The volume occupied by 1.4g of N2 at STP is
(a)    22.4 dm3        (b) 2.24 dm3             (c) 1.12 dm3       (d) 1.12 cm3

  1. Which one of the following statement is not true
(a)    Isotopes with even atomic masses are comparatively abundant
(b)   Isotopes with odd atomic masses are comparatively abundant
(c)    Isotopes with even atomic masses and even atomic numbers are comparatively abundant
(d)   Isotopes with even atomic masses and odd atomic number are comparatively abundant.

  1. One mole of Carbon-12 has mass
(a)    0.012 kg          (b) 1 kg               (c) 0.0224kg      (d) 12 kg

  1. Which of the following compound does not have empirical formula CH2O
(a)    HCHO            (b) C6H12O6             (c) CH3COOH (d) CH3CH2OH

  1. Which one of the following compounds contain the highest percentage by mass of nitrogen
(a)    NH3                        (b) N2H4              (c) NO                (d) NH4OH

  1. The mass of one mole of chlorine gas is
(a)    35.5 g                     (b) 71 g               (c) 23 g               (d) 32 g

  1. One mole of water contains
(a)    81 g   (b) 6.02 x 1023 atoms     (c) 6.02 x 1023 molecules  (d) 6.02 x 1023 ions   

  1. If empirical formula of a compound is CH2O and its molar mass is 180. What will be its actual formula
(a)    CH2O                    (b) C2H4O2           (c) C6H12O6         (d) C4H8

  1. In SI units, the prefix “nano” means
(a)    10-6 m                    (b) 10-9 m             (c) 10-12 m            (d) 10-15 m

  1. Which element cannot be analysed directly by combustion analysis
(a)    Hydrogen           (b) Oxygen           (c) Carbon          (d) Sulphur

  1. Stoichiometeric calculations cannot applied to reversible reactions because
(a)    Product again changes to reactant          (b) Less product is formed
(c)  Reaction goes only in one direction       (d) Products do not disappear

  1. The number of atoms present in 6g of magnesium metal is
(a)    6.02 x 1023        (b) 3.01 x 1023     (c) 12.04 x 1023    (d) 1.5 x 1023

  1. The total number of protons and neutrons present in the nucleus is called
(a)    Mass number  (b) Atomic number (c) Molecular mass (d) Relative atomic mass
  1. The NaCl has 58.5 a.m.u
(a)    Atomic mass    (b) Molecular mass (c) Formula mass   (d) Relative atomic mass
  1. Which one of the following substances is used as water absorber in combustion analysis
(a)    Mg (ClO4)2       (b) 50% KOH     (c) Lime water     (d) Dilute solution of NaOH
  1. Which one of the following properties is always in whole number
(a)    Atomic mass    (b) Atomic radius  (c) Atomic volume  (d) Atomic number
  1. The molecular formula and empirical formula may be
(a)    Identical               (b) Different          (c) Both a & b         (d) None
  1. Actual yield may be less than theoretical yield. It is due to
(a)    Rate of a chemical reaction        (b) Mechanical loss due to filtration
(c)  Controlled mechanism               (d) Irreversibility of reaction

  1. Chlorine atom and chloride ions
(a)    are chemically identical              (b) are allotropes of chlorine
(c)  have same number of electrons  (d) have same number of protons

  1. When one mole of each of the following is completely burnt in oxygen, which gives the largest mass of carbon dioxide
(a)    Diamond                   (b) C2H6                       (c) Methane            (d) CO

  1. The Avogadro constant is the number of
(a)    Atom in 1g of helium gas           (b) Molecules in 35.5g chlorine gas
(c)  Electrons needed to deposit 24g magnesium ions (d) Atoms in 24g of magnesium

  1. What is the mass of one mole of Iodine?
(a)    53 g                             (b) 74 g                       (c) 127 g                  (d) 254 g

  1. Which one of the following is not correct about the isotopes of same element
(a)    Same chemical properties           (b) Same number of electrons
(c)  Different physical properties      (d) Same types of nuclei

  1. In mass spectroscopy, ions are separated on the basis of
(a)    Masses only   (b) Charges only (c) Charge to mass ratio (d) Mass to charge ratio

  1. Which will weigh more
(a)    2 mol N2             (b) 1 mol of O3             (c) 2 mol of O2            (d) 2 mol of CO2

  1. The number of electrons in one mole of H2 is
(a)    6.02 x 1023        (b) 3.01 x 1023              (c) 12.04 x 1023            (d) Indefinite

  1. CO+ is an example of
(a)    Free radical (b) Cationic molecular ion (c) Anionic molecular ion (d) Stable molecule
  1. More abundant isotope of an element is the one with
(a)    Even atomic No.       (b) Odd atomic No.       (c) Odd mass No.       (d) None
  1. The No. of covalent bonds in 10g of NH3 are
(a)    6.02 x 1023           (b) 1.062 x 1023     (c) 10.62 x 1024        (d) 1.062 x 1024
  1. An ordinary optical microscope can measure the size of an object up to or above
(a)    500 nm                         (b) 600 nm            (c) 700 nm                (d) 800 nm
  1. Electron microscope gives
(a)    Beams of electrons instead of visible light (b) Actual produces image of the object
(c)  Actual image of the object smaller than the wavelength of visible light (d) None

  1. The wavelength of electron is than visible light
(a)    Greater                           (b) Shorter           (c) Equal                   (d) None

  1. In twentieth century, x-ray work shows the diameter of atom of the order (m)
(a)    2 x 10-10                         (b) 2 x 10-8          (c) 2 x 10-6                (d) 2 x 10-4

  1. One a.m.u is equal to (in kg)
(a)    1.76 x 10-27                  (b) 1.661 x 10-27 (c) 1.761 x 10-26        (d) 1.661 x 10-26

  1. Formation of negative ion is a type of reaction
(a)    Exothermic                 (b) Endothermic (c) Adiabatic             (d) Isothermal

  1. Molecular ions are formed by
(a)    Bombarding high energy electrons   (b) Bombarding alpha particles  
(c) a and b              (d) None

  1. The relative atomic mass of 6C12
(a)    12.000                     (b) 12.018                   (c) 12.081                  (d) 12.0021

  1. Tin has isotopes
(a)    Five                            (b) Six                        (c) Nine                     (d) Eleven

  1. The relative abundance of isotopes of elements can be determined by spectroscopy
(a)    NMR                         (b) U.V                       (c) I.R                       (d) Mass

  1. Isotopes occur in nature
(a)    240                              (b) 300                       (c) 280                      (d) 380

  1. 16O, 24Mn, 28Si, 40Ca and 56Fe make up of earth crust (%)
(a)    25                                (b) 50                         (c) 75                        (d) 100

  1. The pressure in torr of vapours in mass spectroscopy is kept
(a)    10-6 to 10-7          (b) 10-5 to 10-6             (c) 10-4 to 10-3            (d) None

  1. 1 gm ion of carbonates (CO3-2) is
(a)    64 g                           (b) 56 g                        (c) 60 g                     (d) 48 g

  1. 44 g of CO2 produced from one mole of Carbon and one mole of O2 is called
(a)    Percentage yield     (b) Actual yield       (c) Yield      (d) Theoretical yield 

  1. Which one is not the isotope of carbon?
(a)    6C12                             (b) 6C13                 (c) 6C14                (d) 6C15

  1. Which molecular ions are more abundant in mass spectrum?
(a) Cationic ions        (b) Anionic ions   (c) Halide ions     (d) Alkali metal ions

  1. What is the volume in cm3 of 3.01 x 1023 molecules of O2 gas at S.T.P.
(a) 1000 cm3                 (b) 11000 cm3      (c) 11212 cm3      (d) 22.4 cm3

  1. The empirical formula of glucose is
(a) CH                              (b) CH2O             (c) C6H6                (d) CHO

  1. The S.I units for energy are
(a) Joule                           (b) Calorie           (c) Kelvin              (d) Candela 

50. Which of the following salts will have greater positive charges in its 1 molar aqueous solution?
(a) Ca (OH)2                  (b) KOH              (c) NH4OH            (d) NaOH

           
CHAPTER # 1  (ANSWER  KEY)

1
c
11
b
21
d
31
a
41
b
2
c
12
d
22
d
32
b
42
a
3
a
13
d
23
d
33
a
43
c
4
c
14
c
24
d
34
b
44
d
5
b
15
a
25
d
35
a
45
d
6
b
16
d
26
c
36
c
46
a
7
d
17
c
27
b
37
a
47
c
8
c
18
d
28
a
38
d
48
b
9
d
19
d
29
d
39
d
49
a
10
b
20
b
30
a
40
c
50
a

















I am Mechatronics and Control Engineer from UET, Lahore. Helping Engineering students gives me pleasure.

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