chapter 8 - ktm

Question 1

kinetic theory of matter

Answer 1

based off following assumptions :
i) all matters are made up of tiny particles called atoms or molecules
ii) these particles are in constant motion

Question 2

temperature reading

Answer 2

indication of the average kinetic energy of particles of the substances

Question 3

solid particle arrangement

Answer 3

• closely packed in fixed positions and arranged in regular patterns
• particles vibrate about their fixed positions
• have strong intermolecular forces of attraction between them

Question 4

liquid particle arrangment

Answer 4

• molecules are not arranged in any fixed pattern and they are slightly further apart as compared to solids
• molecules move around randomly and slide over each other throughout the liquid
• the intermolecular forces of attraction is weaker compared to solids

Question 5

gas particle arrangment

Answer 5

• molecules are not arranged in any fixed pattern and they are very far apart as compared to solids
• particles move about randomly at very high speeds
• forces of attraction between particles is very weak

Question 6

what is oberserved in the brownian motion experiment and what causes the particle to move?

Answer 6

• what is observed? - the smoke particles can be seen moving randomly and constantly. (they appear as bright points as they reflect the light that shines on them.)
• what causes the particles to move? - the smoke particles are constantly bombarded by the air molecules

Question 7

how does a thermometer measure the temperature of a substance

Answer 7

the energy in the kinetic store of the particles increases and the particles vibrate about their fixed positions faster. when the thermometer is in contact with the water, the more energetic particles transfer some of the energy to the less energetic particles in the thermometer through collisions. with more energy, the particles tend to push each other further apart and so the matter expands. since liquid expands more easily than solids, the liquid column (normally alcohol) expands noticeably along the calibrated scale.

Question 7

why collisions between air molecules and smoke particles cause smoke particles to move randomly?

Answer 7

1. air molecules are moving in different directions and colliding with the smoke particles in a random and continuous manner
2. air molecules are moving at different speeds due to different temperature of the air molecules

Question 8

why does the energy of a liquid decrease as it turns into a solid?

Answer 8

the liquid gives out latent heat in order to form intermolecular forces among the molecules.