All questions of Atoms, Elements and Compounds for Grade 9 Exam

• a)
  Argon
• b)
  Water vapour
• c)
  Oxygen
• d)
  Nitrogen

• a)
  Compound
• b)
  Molecules
• c)
  Atoms
• d)
  Element

• a)
  Gl
• b)
  Go
• c)
  Si
• d)
  Au

• a)
  Valency 
• b)
  Atomicity 
• c)
  Atomic number 
• d)
  Valence electron

• A:

  Molecule

• B:

  Mixture

• C:

  Compound

• D:

  Atom

The answer is d.

• a)
  Go 
• b)
  Gd 
• c)
  Ge 
• d)
  Au 

• a)
   6.022 × 10²³
• b)
  13
• c)
  52
• d)
  1

• a)
  Empirical formula
• b)
  Molecule
• c)
  Atomicity
• d)
  Compound

• a)
  Einstein
• b)
  Lavoisier
• c)
  Dalton
• d)
  Proust

• a)
  Carbon-12
• b)
  Nitrogen -14
• c)
  Carbon-1
• d)
  4.Silicon-14

• a)
  6.022 x 10²³
• b)
  6.022 x 10²⁰
• c)
  6.022 x 10¹⁵
• d)
  6.022 x 10^-24

• a)
  Na cation and Cl anion
• b)
  Cl cation and Na anion
• c)
  Both Na and Cl cation
• d)
  Both Na and Cl anion

• a)
  4
• b)
  5
• c)
  2
• d)
  3

• a)
  Precipitation reaction
• b)
  Double displacement reaction
• c)
  Neutralization reaction
• d)
  Both A and B

• a)
  15 g
• b)
  5 g
• c)
  50 g
• d)
  10 g

• a)
  2 molecules of chlorine
• b)
  2 atoms of chlorine
• c)
  2 ions of chlorine
• d)
  3 molecule of chlorine

• a)
  1.032 x 10²²
• b)
  6.886 × 10²³
• c)
  3.88 x 10²² 
• d)
  1.302 x 10²² 

• a)
  A mole of an element
• b)
  A mole of a compound
• c)
  An atom of an element
• d)
  An atom of a compound

• a)
  N₂
• b)
  N
• c)
  N₃
• d)
  Ni

• a)
  Lithium
• b)
  Helium
• c)
  Hydrogen
• d)
  Carbon

• a)
  In the form of molecules
• b)
  In the form of ions
• c)
  In the free state
• d)
  In the form of molecules and Ions

• a)
  Law of conservation of mass
• b)
  Laws of Chemical combination
• c)
  Law of constant proportions
• d)
  Dalton’s Atomic theory

• a)
  6.022 x 10^-23 atoms of carbon
• b)
  6.022 X 10^-23 atoms of oxygen
• c)
  6.022 x 10²³ molecules of CO₂
• d)
  3g atom of CO₂

• a) 
  Cavendish
• b) 
  Proust
• c) 
  Dalton
• d) 
  Lavoisier

• a)
  (i) and (ii) 
• b)
  (i), (ii) and (iii) 
• c)
  (ii), (iii) and (iv) 
• d)
  (i), (iii) and (iv) 

• a)
  (a) and (b) are correct
• b)
  (a), (b) and (c) are correct
• c)
  (b) and (c) are correct
• d)
  All of these

• a)
  Elements can be changed into simpler substances. 
• b)
  Compound has variable composition 
• c)
  The mixture has properties similar to its components. 
• d)
  Brass is a compound of Copper and Zinc

• a)
  1.11%
• b)
  11.11%
• c)
  8.89 %
• d)
  88.9%

• a)
  6.023 x 10²³ N₂ molecules 
• b)
  22.4 L of N₂ at STP 
• c)
  6.023 x 10²³ nitrogen atoms 
• d)
  28 g of nitrogen.

• a)
  HS
• b)
  H₂S₂
• c)
  HS₂
• d)
  H₂S

• a)
  They are very stable.
• b)
  They are electrically charged.
• c)
  They are very reactive.
• d)
  They are bigger in size as compared to atoms.

• a)
  2.3 g 
• b)
  3.5 g 
• c)
  5.8 g 
• d)
  0.23 g 

• a)
  Scanning tunneling microscope
• b)
  Microscope
• c)
  Most powerful microscope
• d)
  Optical microscope

• a)
  136.3 u
• b)
  124 u
• c)
  123 u
• d)
  111 u

• A:

  Silver – Si

• B:

  Sodium – So

• C:

  Potassium – Pt

• D:

  Sulphur – S

The answer is d.

• a)
  16 g 
• b)
  8 g 
• c)
  4 g 
• d)
  2 g 

• a)
  4g oxygen and 16g hydrogen
• b)
  2g hydrogen and 1g oxygen
• c)
  8g oxygen and 1g hydrogen
• d)
  none

• a)
  Law of constant proportion
• b)
  Law of conservation of mass
• c)
  Law of conservation of mass and Law of constant proportion
• d)
  Law of multiple proportion

• a)
  Law of conservation of mass
• b)
  Law of multiple proportions
• c)
  Law of definite proportion
• d)
  Law of combining volumes

• a)
  The reactants must contain more complex molecules than the products do.
• b)
  The products must have different physical state than the reactants.
• c)
  The total mass of the reactants must equal the total mass of the products.
• d)
  The density of the reactants must equal the density of the products.

• a)
  The number of atoms in a given compound is fixed.
• b)
  Atoms of the same elements cannot combine in more than one ratio to form more than one compound.
• c)
  Atoms can neither be created nor destroyed.
• d)
  Atoms cannot be divided.

• a)
  CaCI
• b)
  NaS0₄ 
• c)
  NaS
• d)
  NaCI

• a)
  1.70 g of AgN0₃ reacts with 0.01 mol of HCl to form 1.435 g of AgCl and 0.63 g of HNO₃
• b)
  12 g of CO reacts with 32 g of 0₂ to form 44 g of C0₂ 
• c)
  12 g of C is heated in vacuum and cooling there is no change in mass
• d)
  100 g of ice forms 100 g of water liquid on melting

• a)
  In a chemical reaction, efforts should be made to preserve rare elements without changing them.
• b)
  In a chemical reaction, the final mass of the products is always greater than the starting mass of the reactants.
• c)
  In a chemical reaction, matter is not created or destroyed, but is conserved.
• d)
  Matter can be created and destroyed but does not change forms.

• a)
  All matter is made up of very tiny particles called atoms.
• b)
  Atoms can be divided into proton, neutron and electrons.
• c)
  Atoms of given element are identical in mass and chemical properties.
• d)
  Atoms combine in the ratio of small whole numbers to form compounds.

• a)
  1/12 of the mass of one ¹²C atom
• b)
  6.022 x 10²³ g
• c)
  12g
• d)
  l g

Match the following with correct response. 

• a)
  1-D, 2-A, 3-C, 4-B
• b)
  1-C, 2-B, 3-D, 4-A
• c)
  1-A, 2-C, 3-B, 4-D
• d)
  1-B, 2-D, 3-A, 4-C

• a)
  100 
• b)
  200 
• c)
  300 
• d)
  400 

• a)
  1 g
• b)
  1.99 x 10^-23g
• c)
  1/12 g
• d)
  1.99 x 10²³ g