Phases of Matter

Question 1

Macroscopic properties

Answer 1

Properties that can be observed and measured at a large scale and are visible to the eye. E.g., mass, volume, temperature

Question 2

Microscopic properties

Answer 2

Properties on an atomic/molecular scale. Not directly observable, e.g., arrangement of atoms, vibrations and forces.

Question 3

Macroscopic:

Answer 3

Condensed - difficult to compress (S, L)
Fluid - flows easily (L, G)

Question 4

Microscopic:

Answer 4

Particle separation - distance between particles in different states of matter. (G>L>S)
Particle motion - The way particles move in different states of matter (G>L>S)

Question 5

How macro and micro properties are related

Answer 5

A phase with large particle separation can be easily compressed.
A phase with large translation motion can flow.

Question 6

Types of particle motion

Answer 6

Translational, rotational and vibrational

Question 7

Atomic gas

Answer 7

T

Question 8

Molecular gas

Answer 8

T, R , V

Question 9

Atomic liquid

Answer 9

T

Question 10

Molecular liquid

Answer 10

T, R , V

Question 11

Atomic/ionic solid

Answer 11

V

Question 12

Molecular solid

Answer 12

V, (R) sometimes

Question 13

Detecting motion: spectroscopy

Answer 13

Different types of motion have quantised energy levels, meaning specific frequencies of light are absorbed or emitted depending on the type of motion.

Question 14

Detecting motion: thermal energy

Answer 14

Measured using heat capacity. The more energy needed to increase temperature, the more forms of motion present.

Question 15

Order

Answer 15

If material is ordered, it has a regular and repeating structure (crystalline solids). Gases are always disordered, but solids and liquids can exist in ordered and disordered states.

Question 16

How order is detected

Answer 16

Diffraction: if an x-ray is passed through ordered material, some of them will be diffracted by a precise angle defined by the repeating structure. The diffraction pattern can thus be used to determine the structure and order.

Question 17

Properties influenced by order

Answer 17

Many crystalline materials have birefringence, where they split a ray of light in two when assing through.

Question 18

Interparticle interactions

Answer 18

Dependent on separation and chemical nature of particles. In gases, there is large separation; therefore, there are minimal forces between particles.

Question 19

Electrostatic interactions

Answer 19

When charged atoms or molecules are present, an electric force will exist between them. Like charges repel and opposites attract, which is responsible for bonding in simple salts, e.g. NaCl.

Question 20

Van der Waals interactions

Answer 20

Neutral molecules interact with one another through non-uniform charge distributions that occur as a result of orbiting electrons. A dipole on one molecule can induce a dipole in another, resulting in attractive force.

Question 21

Hydrogen bonding

Answer 21

Interaction between a ydrogen atom and an electronegative atom in another molecule. Strong and directional bonds (influenced by molecular geometry)

Question 22

Repulsive interactions

Answer 22

All molecules and atoms experience attractive and repulsive interactions. R dominates when they are too close and A dominates when they are too far apart.

Question 23

Phase transitions

Answer 23

Phases can transition between one another at different temperatures and pressures. In a phase diagram, the triple point is the unique combination of pressure and temperature at which all phases are stable.