Basic Concepts in Chemistry

Matter
- Anything that occupies space and has mass.
- Exists in three states: solid, liquid, gas.
Atoms
- Basic unit of matter.
- Composed of protons (positively charged), neutrons (neutral), and electrons (negatively charged).
- Atomic number = number of protons.
Elements
- Pure substances made up of one type of atom.
- Organized in the Periodic Table based on atomic number.
Compounds
- Substances formed when two or more elements chemically bond.
- Example: Water (H₂O) is made from hydrogen and oxygen.

Ionic Bonds
- Formed through transfer of electrons.
- Occurs between metals and non-metals.
Covalent Bonds
- Formed when two atoms share electrons.
- Typically occur between non-metals.
Metallic Bonds
- Allow for electron flow between metal atoms.
- Contributes to conductivity and malleability of metals.

Types of Reactions
- Synthesis: Two or more substances combine to form one compound.
- Decomposition: A compound breaks down into simpler substances.
- Single Replacement: One element replaces another in a compound.
- Double Replacement: Exchange of ions between two compounds.
- Combustion: Reaction with oxygen to produce energy, CO₂, and H₂O.
Law of Conservation of Mass
- Mass is neither created nor destroyed in a chemical reaction.

Mole Concept
- A mole is 6.022 x 10²³ particles (Avogadro's number).
- Used to relate mass, volume, and the number of particles in reactions.
Balancing Equations
- Chemical equations must be balanced to reflect conservation of mass.
- Coefficients are used to balance the number of atoms of each element.

Acids
- Substances that donate protons (H⁺) in a solution.
- Characteristics: sour taste, pH < 7, can conduct electricity.
Bases
- Substances that accept protons or donate hydroxide ions (OH⁻).
- Characteristics: bitter taste, slippery feel, pH > 7.
pH Scale
- Measures acidity/basicity of a solution from 0 (acidic) to 14 (basic), with 7 being neutral.

Energy Changes
- Endothermic reactions absorb energy; exothermic reactions release energy.
- Enthalpy (ΔH) indicates the heat content of a reaction.
Law of Thermodynamics
- Energy cannot be created or destroyed, only transformed.

Hydrocarbons
- Compounds primarily composed of carbon and hydrogen.
- Types include alkanes (single bonds), alkenes (double bonds), and alkynes (triple bonds).
Functional Groups
- Specific groups of atoms that determine the properties and reactions of organic molecules.
- Examples: hydroxyl (-OH), carboxyl (-COOH), amino (-NH₂).

Salts and Minerals
- Formed from ionic bonds between metals and nonmetals.
- Can be soluble or insoluble in water.
Coordination Compounds
- Composed of a central metal atom bonded to surrounding ligands.
- Important in biological systems (e.g., hemoglobin).

Titration
- Technique used to determine the concentration of a solute in a solution.
- Involves a reaction between the analyte and titrant.
Chromatography
- Method for separating mixtures into individual components.
- Based on different affinities for a stationary vs. mobile phase.

Matter is anything that takes up space and has mass.
- Exists in three states: solid, liquid, gas.
Atoms are the basic units of matter.
Atoms composed of protons, neutrons, and electrons.
- Protons have a positive charge, while neutrons have no charge.
- Electrons have a negative charge.
The atomic number of an element equals the number of protons in its atom.
Elements are pure substances made up of only one type of atom. They are arranged in the periodic table based on atomic number.
Compounds are formed when two or more elements chemically combine.
- Example: Water (H₂O) is a compound made up of hydrogen and oxygen.

Ionic bonds are formed by the transfer of electrons between atoms.
- Occur between metals and non-metals.
Covalent bonds involve the sharing of electrons between two atoms.
- Typically occur between nonmetals.
Metallic bonds occur between metal atoms allowing electrons to flow freely between atoms. This contributes to properties like conductivity and malleability.

Synthesis reactions combine two or more substances to form a single compound.
Decomposition reactions break down a compound into simpler substances.
Single replacement reactions involve the replacement of one element by another in a compound.
Double replacement reactions involve the exchange of ions between two compounds.
Combustion reactions involve the reaction of a substance with oxygen producing energy, CO₂ and H₂O.
The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction.

A mole represents 6.022 x 10²³ particles, this is known as Avogadro's number.
Moles are essential for relating mass, volume, and the number of particles in chemical reactions.
Chemical equations must be balanced to reflect the conservation of mass.
- Coefficients are used to balance the number of atoms of each element in the equation.

Acids donate protons (H⁺) when dissolved in a solution.
- They typically taste sour, have a pH below 7 and conduct electricity.
Bases accept protons or donate hydroxide ions (OH⁻) in a solution.
- They are typically bitter, feel slippery, and have a pH above 7.
The pH scale measures the acidity or basicity of a solution.
- It ranges from 0 (most acidic) to 14 (most basic) with 7 being neutral.

Endothermic reactions absorb energy from their surroundings.
Exothermic reactions release energy into their surroundings.
Enthalpy (ΔH) indicates the heat content of a chemical reaction.
The Law of Thermodynamics states that energy cannot be created or destroyed, only transformed.

Hydrocarbons are compounds composed primarily of carbon and hydrogen.
- Alkanes, alkenes, and alkynes differ in the types of bonds between their carbon atoms.
  - Alkanes have single bonds
  - Alkenes have double bonds
  - Alkynes have triple bonds
Functional groups are specific groups of atoms that determine the properties and reactions of organic molecules.
- Examples include hydroxyl (-OH), carboxyl (-COOH), and amino (-NH₂).

Salts and minerals are formed through ionic bonds between metals and nonmetals.
- They may be soluble or insoluble in water.
Coordination compounds contain a central metal atom bonded to surrounding ligands.
- These compounds are important in biological systems, like hemoglobin.

Titration is a technique used to determine the concentration of a solute in a solution.
- It involves a reaction between the analyte and titrant.
Chromatography is a method used to separate mixtures into their individual components.
- It relies on the different affinities of the components for a stationary vs. mobile phase.