10th Class Chemistry 1st Quarter Book Paper

Q1. Multiple choice questions (Attempt all · 12 × 1 = 12)

1. Once bound with the reactant molecule, the particular chemical bonds in the reactant molecule are:

   1. Strengthened

   2. Broken completely into ions

   3. Sufficiently weakened

   4. Replaced by metallic bonds

2. What happens to the movement of particles when a gas is cooled?

   1. They repel each other more

   2. They disappear

   3. They move faster

   4. Their kinetic energy decreases

3. Which catalyst is commonly used in the porous carbon electrodes of a fuel cell?

   1. Copper

   2. Zinc

   3. Platinum

   4. Iron

4. What is the first step in identifying a limiting reactant?

   1. Balance the chemical equation

   2. Calculate the number of moles of the reactants

   3. Measure the room temperature

   4. Discard the excess reactant

5. When reactant particles come close to each other at the time of collision, their kinetic energy converts into:

   1. Potential energy

   2. Chemical energy

   3. Heat energy

   4. Electrical energy

6. At a given temperature, lighter gases diffuse:

   1. Slower

   2. Slower

   3. At same rate

   4. Not at all

7. During electrolysis, the molten lead is maintained in a heated crucible above:

   1. 100°C

   2. 300°C

   3. 500°C

   4. 1000°C

8. The concept of molar volume helps us to calculate the number of moles of a gas if we know its:

   1. Temperature

   2. Pressure

   3. Volume

   4. Density

9. The matter is composed of tiny, constantly moving particles according to which theory?

   1. Atomic theory

   2. Kinetic theory

   3. Collision theory

   4. Quantum theory

10. A student noticed frost falling on the ground at 6.30 am and disappearing by 8.30 am. Which phase change was responsible for changing the frost into water vapours?

    1. Melting

    2. Evaporation

    3. Sublimation

    4. Deposition

11. During oxidation, the oxidation number or oxidation state of an element always:

    1. Decreases

    2. Increases

    3. Remains zero

    4. Becomes negative

12. Titration is a technique used to find the concentration of a solution by reacting it with:

    1. Water only

    2. Solution of known concentration

    3. Insoluble salt

    4. Gaseous catalyst