Physics of Energy and Change

Study Notes

Forms of Energy:
- Kinetic Energy (motion)
- Potential Energy (stored energy)
- Thermal Energy (heat)
- Electrical Energy
- Chemical Energy
- Nuclear Energy
Energy Conversion: Energy can change from one form to another, but the total energy remains constant (Law of Conservation of Energy)
Energy Transfer: Energy can be transferred from one object to another through various means, such as heat, work, or radiation

Types of Change:
- Physical Change: a change in which the substance changes form, but not composition (e.g., ice → water → steam)
- Chemical Change: a change in which the composition of the substance changes (e.g., rusting of iron)
Factors Affecting Change:
- Temperature
- Pressure
- Concentration
- Surface Area
- Catalysts
Rate of Change: the speed at which a change occurs, influenced by the factors listed above
Reversibility: some changes are reversible (e.g., melting and freezing), while others are irreversible (e.g., burning of wood)

Energy Required for Change: energy is often required to initiate or sustain a change
Energy Released During Change: energy can be released during a change, such as heat during combustion
Equilibrium: a state in which the rates of forward and reverse changes are equal, resulting in no net change

There are six main forms of energy: kinetic, potential, thermal, electrical, chemical, and nuclear energy
Energy can convert from one form to another, but the total energy remains constant, as stated by the Law of Conservation of Energy
Energy can transfer from one object to another through heat, work, or radiation

Physical changes occur when a substance changes form but not composition, such as ice turning into water and then steam
Chemical changes occur when the composition of a substance changes, such as the rusting of iron
Factors that affect change include temperature, pressure, concentration, surface area, and catalysts
The rate of change is influenced by the aforementioned factors
Some changes are reversible, like melting and freezing, while others are irreversible, like burning wood

Energy is often required to initiate or sustain a change
Energy can be released during a change, such as heat during combustion
Equilibrium occurs when the rates of forward and reverse changes are equal, resulting in no net change

The smallest unit of matter is the atom, composed of protons, neutrons, and electrons.
Protons are positively charged particles found in the nucleus of an atom.
Neutrons have no charge and are also found in the nucleus.
Electrons are negatively charged particles found in energy levels around the nucleus.
The atomic number is the number of protons in an atom, which determines an element's identity.
The atomic mass is the total number of protons and neutrons in an atom.

A chemical bond is the attractive force that holds two or more atoms together.
Ionic bonds form when electrons are transferred between atoms, resulting in ions with opposite charges.
Covalent bonds form when electrons are shared between atoms, resulting in a molecule.
Hydrogen bonds are weak bonds between hydrogen atoms and highly electronegative atoms, such as oxygen or nitrogen.

The periodic table organizes elements by their atomic number (number of protons) and chemical properties.
Elements in the same period (row) have similar energy levels, while elements in the same group (column) have similar chemical properties.
The periodic table allows us to predict the chemical behavior of elements based on their position in the table.

Kinetic energy is the energy of motion, associated with an object's velocity.
Potential energy is stored energy that can be converted into kinetic energy.
Thermal energy is the energy of heat, associated with an object's temperature.
Electrical energy is the energy of moving charged particles, such as electrons.
Chemical energy is the energy stored in chemical bonds, which can be released through chemical reactions.

Energy can be transferred from one object to another through various means, such as heat, work, or radiation.
Energy can be transformed from one type to another, such as from kinetic to thermal energy.

The First Law of Thermodynamics states that energy cannot be created or destroyed, only transferred or transformed.
The Second Law of Thermodynamics states that the total entropy (disorder or randomness) of a closed system always increases over time.

A chemical reaction is a process in which one or more substances (reactants) are converted into new substances (products).
A chemical equation represents a chemical reaction using chemical formulas and symbols.
Chemical equilibrium occurs when the rates of forward and reverse reactions are equal, resulting in a stable mixture of reactants and products.