GETTING ON WITH ENGLISH IN THE LAB 2n ESO: 2+2=4 (BUT NOT ALWAYS)

The molecular-kinetic theory

OBJECTIVE:

• Understanding the molecular-kinetic theory.

INTRODUCTION:

The  molecular-kinetic theory of matter is a theory that explains the properties and behaviour of the various states of aggregation of matter.

The molecular-kinetic theory is based on three assumptions:

1. The matter consists of very small particles, almost invisible unless you have an electronic microscope.

2. The particles do forces of attraction between them that held together: In the solid strength is very large; in liquids, moderate and gases, very small.

3. The particles are in constant motion: the solid particles hardly move, vibrate only. The gas particles move independently of each other, and the liquid is given an intermediate situation. Remember that the higher the temperature of matter, its particles vibrate more.

MATERIAL:

1. A graduated cylinder of 100ml

2. 2 graduated cylinder of 50 ml

3. chickpeas and rice

4. Ethanol

5. Water

PROCEDURE AND COMMENTS:

This experience seems to defy the laws of mathematics.

i. Mix 50 ml of chickpeas with 50 ml of rice. What is the volume of the mixture?

ii. How can we explain this fact?

iii. If you mix 50 ml of water with 50 ml of ethanol, what do you think will be the final volume of the solution?

iv. Take this mixture in a agraduated cylinder. What is the volume of the solution?

v. What relationship do you think there might be between this and the previous experiment?

vi. Justify from the molecular-kinetic theory the fact that the volume of the solution is not 100 ml.

vii. Does it happen the same  if we do the  experiment with two immiscible liquids like water and oil?