How do we know that a substance has changed state from solid to liquid at a molecular level?

Match the following:

State	Attributes
a. Solid	i. Highest kinetic energy of the molecules
b. Liquid	ii. Highest potential energy of the molecules
c. Gas	iii. Moderate K E and P E

1. a-ii, b-iii, c-i
2. a-i, b-iii, c-ii
3. a-iii, b-ii, c-i
4. a-i, b-ii, c-iii

In which of the following physical states the intermolecular space is the highest?

1. Solid
2. Liquid
3. Gas
4. All of the above

What kind of energy is associated with the motion and speed of the particles constituting a substance?

1. Potential energy
2. Kinetic energy
3. Gravitational potential energy
4. Elastic energy

Internal energy = _____ + _______.

1. Gravitational energy, potential energy
2. Kinetic energy, potential energy
3. Kinetic energy, thermal energy
4. Thermal energy, gravitational energy

The particles of a substance possess _____.

1. Speed
2. Kinetic energy
3. Potential energy
4. All of the above

The molecules of which form of water have the highest kinetic energy?

1. Ice
2. Water
3. Steam
4. Jelly 

When an ice cube is dropped into a cup of hot coffee, the heat flows from _________.

1. Ice to coffee
2. Coffee to ice
3. Nowhere
4. Surrounding to coffee

The force of attraction between the water molecules gives rise to _________________.

1. Kinetic energy
2. Potential energy
3. Gravitational energy
4. Electrostatic energy

1 cal = ___ J

1. 1000
2. 2.4
3. 4.2
4. 3.6

1 kcal = ____ cal.

1. 100000
2. 10000
3. 1000
4. 100

1 Joule = ________________ Erg.

1. 10000000
2. 1000000
3. 100000
4. 10000

The S I unit of heat is _____________.

1. Calorie
2. Kilocalorie
3. Erg
4. Joule

Malvika keeps melted ice-cream in the freezer for it to freeze back. Which of the following happens to the ice-cream?

1. The speed of motion of the particles increases.
2. The kinetic energy of the particles decreases.
3. The amount of heat inside the container decreases.
4. The temperature of ice-cream decreases.

Four systems are at the following temperatures in degree Celsius. the speed of particles of which of the systems is the lowest?

1. 35
2. 87
3. 12
4. 76

100 degrees Celsius = ____ degree Fahrenheit.