Olympiad – Class X – Science - Che - Chemical Reactions and Equations

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Question - 1

What is the reaction in which a substance or substances undergo change to produce new substances with new properties called?

  • A A biochemical reaction
  • B A nuclear reaction
  • C A physical reaction
  • D A chemical reaction

Question - 2

Which substances take part in a chemical reaction?

  • A Products
  • B Reactants
  • C Mixtures
  • D Compounds

Question - 3

Which of these substances are formed as a result of a chemical reaction?

  • A Products
  • B Reactants
  • C Mixtures
  • D Compounds

Question - 4

Which of the following conditions is necessary for a chemical reaction?

  • A It must be accompanied with change in temperature and pressure
  • B At least one of the reactants must be in a fixed quantity.
  • C It must follow the law of conservation of mass
  • D All of the above

Question - 5

Which of the following is the shorthand representation of a chemical reaction?

  • A A symbol
  • B A formula
  • C An equation
  • D All of the above

Question - 6

'x' is an equation which contains equal number of atoms of each element on both the sides. What is 'X'?

  • A A balanced equation
  • B An unbalanced equation
  • C A chemical equation
  • D All of the above

Question - 7

In the given equation, what does 'X' stand for?
(2)Al + (X)H2SO4 \(\rightarrow\) Al2(S04)3 +(3)H2

  • A 2
  • B 3
  • C 1
  • D 5

Question - 8

Which of the following are correct about a chemical equation?
(i)It saves time and space in writing.
(ii) It does not indicate the rate of a reaction.
(iii) It tells the ratio of the masses of the reactants and products

  • A Only (i) and (ii)
  • B Only (ii) and (iii)
  • C Only (i) and (iii)
  • D (i), (ii) and (iii)

Question - 9

Which of the given chemical equations is NOT balanced?

  • A 3Fe + 4H2O\(\rightarrow\) Fe3O4 + 4H2
  • B KClO3 \(\rightarrow\) KCl + O2
  • C CaCO3 \(\rightarrow\) CaO + CO2
  • D Mg + 2HCl \(\rightarrow\) MgCl2 + H2

Question - 10

Which of the given chemical equations is balanced?

  • A H2O2\(\rightarrow\)H2O+O2
  • B NaNO3 \(\rightarrow\) NaNO2 + O2
  • C CaCO3\(\rightarrow\)CaO + CO2
  • D Al2CO3 \(\rightarrow\) Al2O3 + CO2