Available Answers

1. 1.

   Choose and write the correct answer(MCQs):

   1. New substance is formed in a ______________  change.
      1. physical
      2. reversible
      3. chemical
      4. irreversible
   2. The substance that take part in a chemical reaction are called _____________.
      1. reactant
      2. products
      3. both of these
      4. none of these
   3. The reaction 2Mg + O₂ → MgO shows ____________ reaction.
      1. oxidation
      2. reduction
      3. combination
      4. none of these
   4. In the reaction, CuO + H₂→ Cu + H₂O, the oxidising agent is _____________.
      1. Cu
      2. H₂O
      3. H₂
      4. CuO
   5. C + O₂ → CO2, is a ______________ reaction.
      1. decomposition
      2. oxidation
      3. reduction
      4. displacement
2. 2.

   Fill in the blanks:

   1. Chemical reactions that give off energy is ________________.
   2. C + O₂ → __________________ + heat + light.
   3. Heat energy is absorbed in ________________ reactions.
   4. The process of oxidation involves the addition of __________________.
   5. Limestone is burnt to obtain ___________________.
   6. Glowing of a filament bulb is an example of ________________.
3. 3.

   Define a physical change.
4. 4.

   Define a chemical change.
5. 5.

   Give two examples of physical and chemical changes.
6. 6.

   Name the various types of chemical reactions.