Chemistry - 9 Chapter - 6State of MatterTest - 4

Chemistry - 9 Chapter - 6
State of Matter
Test - 4

1. Molecules of ice are held together by _____ forces.

a) Vander wall
b) Electrostatic
c) Cohesive
d) Electromagnetic

2. Why ice melts at very low temperature?

a) Because its molecules are held with very weak Vander walls forces
b) Because its molecules are held with very weak electrostatic forces

3. Ice melts at very low temperature because its molecules are held with very weak Electrostatic forces.

a) False
b) True

4. Why solid substances maintain a certain volume and shop?

a) Due to very weak cohesive forces between their atoms and molecules.
b) Due to very strong cohesive forces between their atoms and molecules.

5. Particles of solids also move like liquid and gas, but their motion is only vibration

a) False
b) True

6. What is the simplest method of changing the state of solid substance

a) Grinding
b) Heatinf
c) Cutting
d) Breaking

7. What happens to the particles when a solid substance is heated? .......... Kinetic energy of particles increases and they start vibrating at a higher frequency. At a particular temperature cohesive forces are overcome and solids ------.

a) melt
b) evaporates

8. When a solid melts?

a) When a particular temperature for each solid substance is reached, cohesive forces are overcome due to increase in the kinetic energy of particles and solids melts.
b) When a 100 C temperature for each solid substance is reached, cohesive forces are overcome due to increase in the kinetic energy of particles and solids melts.

9. What is sublimation?

a) Some solids, upon heating, change directly into vapors instead of changing into liquid. This is called sublimation.
b) Some liquids, upon heating, change directly into vapors instead of boiling. This is called sublimation.

10. What is Condensation?

a) Cooling the molecules of some compounds change them directly into solid state. This phenomenon is called
b) Cooling the vapors of some compounds change them directly into solid state. This phenomenon is called

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