Introduction to Chemistry

Chemistry

• Chemistry is the scientific study of matter, its properties, composition, and the changes it undergoes.
• Matter is anything that has mass and occupies space.

Branches of Chemistry

• Organic chemistry: Study of carbon-containing compounds.
• Inorganic chemistry: Study of non-carbon containing compounds.
• Physical chemistry: Study of the physical properties of matter and the changes it undergoes.
• Analytical chemistry: Study of the composition of matter.
• Biochemistry: Study of the chemical processes in living organisms.

States of Matter

• Solids: Have a definite shape and volume, and particles are tightly packed.
• Liquids: Have a definite volume but no definite shape, and particles are close together but can move past each other.
• Gases: Have no definite shape or volume, and particles are far apart and move freely.

Atomic Structure

• Atoms are the basic units of matter.
• Atoms consist of a nucleus containing protons (positively charged) and neutrons (neutral), and electrons (negatively charged) orbiting the nucleus.
• The number of protons in an atom's nucleus determines its atomic number and element.

Chemical Bonds

• Ionic bonds: Formed by the transfer of electrons from one atom to another, creating ions with opposite charges that attract.
• Covalent bonds: Formed by the sharing of electrons between atoms.
• Metallic bonds: Formed by the sharing of many electrons among a group of metal atoms.

Chemical Reactions

• Chemical reactions involve the rearrangement of atoms to form new substances.
• Chemical equations represent chemical reactions using chemical formulas and symbols.
• Reactants are the substances that undergo a change, while products are the substances formed.
• Balancing chemical equations ensures that the number of atoms of each element is the same on both sides of the equation (law of conservation of mass).

Periodic Table

• The periodic table organizes elements based on their atomic number and recurring chemical properties.
• Elements in the same column (group) have similar properties due to similar electron configurations.
• Elements in the same row (period) show gradual changes in properties.

Solutions

• Solutions are homogeneous mixtures of two or more substances.
• The solvent is the dissolving medium, and the solute is the substance being dissolved.
• Concentration expresses the amount of solute in a given amount of solvent.

Acids and Bases

• Acids have a sour taste and produce hydrogen ions (H+) when dissolved in water.
• Bases have a bitter taste and slippery feel and produce hydroxide ions (OH-) when dissolved in water.
• The pH scale measures the acidity or basicity (alkalinity) of a solution.

Stoichiometry

• Stoichiometry is the calculation of quantitative relationships between reactants and products in chemical reactions using the balanced chemical equation. This involves molar ratios and mass-to-mass calculations.

Thermodynamics

• Thermodynamics studies energy changes in chemical reactions, focusing on enthalpy (heat changes) and entropy (disorder).
• Exothermic reactions release heat to the surroundings, while endothermic reactions absorb heat from the surroundings.

Kinetics

• Kinetics studies the rates of chemical reactions and the factors affecting them.
• Reaction rates depend on factors like temperature, concentration, catalysts, and surface area.

Nuclear Chemistry

• Nuclear chemistry focuses on radioactive decay and nuclear reactions.
• Radioactive decay involves the spontaneous disintegration of unstable atomic nuclei.
• Nuclear reactions involve changes in the nucleus of an atom.