B. The particulate nature of matter

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2024/06/24 03:17

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B.1.1 Molecular theory of solids, liquids and gases

Understanding: Properties of the three states of matter considered in physics

Particle Model of Matter:

B.1.1-1 Diagram of 3 main states

Model that attempts to explain the properties of the three states of matter

Properties of a Solid:

Atoms are fixed in place by a strong force (or bond) between each other. → Strong intermolecular force between atoms (fixed structure)

This force prevents the atoms from separating and keeps the volume and shape constant

Greater distances → attractive force (energy released during bond formation), shorter distances → repulsive force

The attractive intermolecular force between the atoms in the solid means energy is required to move atoms away from each other and energy is released when the atoms move closer

Lowest potential energy

B.1 Thermal Energy Transfer

B.2.1 Conduction, convection, and thermal radiation

Conduction, Convection and Thermal Radiation

Conduction is when energy is transferred by direct contact

Usually happens in solid

When two solids in different temperatures contact conduction happens

Metal are good thermal conductors because :

Non-metal are poor thermal conductors because :

Convection is when energy is transferred by the mass motion of molecules

Mainly happens in liquids and gases

When a liquid is heated convection happens

B.2.1-2 Diagram showing the convection

B.2 Greenhouse Effect

B.3.1 Avogadro constant, Pressure, and Gas Laws

Molar Concept Rules

Boyle’s Law : Pressure of a gas of fixed mass and at a constant temperature is inversely proportional to its volume

This means that the product of p and V is always constant

p_1 V_1 = p_2 V_2 = \textit{constant}

Charles’s Law : Volume of a gas of fixed mass and constant pressure is directly proportional to its temperature

V ∝ T

Which means V divided by T is always constant

\frac{V_1}{T_1} = \frac{V_2}{T_2}, \quad V_1 T_2 = V_2 T_1 = \textit{constant}

B.3.1-2 Diagram of particles at low temperature and high temperature and graph representing relationship between volume and temperature

Gay Lussac’s Law : Pressure of a gas of fixed mass and volume is directly proportional to its temperature

p \propto T

B.4.1 Basic Definitions

Internal Energy

Types of Systems

Closed system

Isolated system

Sign Convention

Clausius’ sign convention

B.4.1 First Law of Thermodynamics

First Law of Thermodynamics

Work Done by a Closed System

Change in Internal Energy

B.4 Thermodynamics

B.5.1 Ohm's Law

Mathematical Approach of Ohm’s Law

As mentioned previously, whenever there is a potential difference there must be an electric field

When a potential difference is established at the ends of a conductor, an electric field is established within the conductor that forces electrons to move and create the current

The size of the current is different in the different conductors, as each conductor will operate with different efficiency

The properties of the conductors to resist the current flow is called electric resistance

The equation of resistance is :

R=\frac VI

B.5.1-1 Equations explaining Ohm’s Law with notations

B.5.1-1 Equations explaining Ohm’s Law with notations

This relationship, we called it ohm’s law, and the unit is ohm, symbol

Materials that obey ohm’s law have a constant resistance in any circumstances

For those ohmic materials, a graph of I versus V gives a straight line through the origin

B.5.1-2 Graph of current against voltage in ohmic materials

B.5 Current and Circuits