Chemical Reactions

Study Notes

Chemical reactions involve the transformation of one or more substances into new substances.
Types of chemical reactions:
- Synthesis: two or more substances combine to form a new substance.
- Decomposition: a single substance breaks down into two or more substances.
- Replacement: one element replaces another in a compound.
- Combustion: a substance reacts with oxygen to produce heat and light.
Chemical reactions are often represented by chemical equations, which show the reactants, products, and direction of the reaction.

Matter is used in various everyday applications, including:
- Food and drink: cooking, digestion, and nutrition.
- Medicine: diagnosis, treatment, and prevention of diseases.
- Technology: construction of buildings, roads, and electronic devices.
- Energy: fossil fuels, nuclear power, and renewable energy sources.

Matter can exist in four main states:
- Solid: particles are closely packed and have a fixed shape.
- Liquid: particles are close together but can move freely.
- Gas: particles are widely spaced and can move freely.
- Plasma: high-energy state where particles are ionized.
Phase changes occur when matter changes from one state to another, such as melting (solid to liquid) or boiling (liquid to gas).

Mixtures are composed of two or more substances that are not chemically combined.
Methods for separating mixtures:
- Filtration: separating particles based on size.
- Sedimentation: separating particles based on density.
- Distillation: separating liquids based on boiling points.
- Chromatography: separating particles based on their interactions with a stationary phase.

Transformation of one or more substances into new substances occurs in chemical reactions.
Four main types of chemical reactions: synthesis, decomposition, replacement, and combustion.
Synthesis reaction: two or more substances combine to form a new substance.
Decomposition reaction: a single substance breaks down into two or more substances.
Replacement reaction: one element replaces another in a compound.
Combustion reaction: a substance reacts with oxygen to produce heat and light.
Chemical reactions are represented by chemical equations, showing reactants, products, and direction of the reaction.

Matter is used in various everyday applications.
Food and drink: cooking, digestion, and nutrition involve chemical reactions.
Medicine: diagnosis, treatment, and prevention of diseases rely on chemical reactions.
Technology: construction of buildings, roads, and electronic devices use chemical reactions.
Energy: fossil fuels, nuclear power, and renewable energy sources involve chemical reactions.

Mixtures are composed of two or more substances that are not chemically combined.
Methods for separating mixtures: filtration, sedimentation, distillation, and chromatography.
Filtration: separating particles based on size.
Sedimentation: separating particles based on density.
Distillation: separating liquids based on boiling points.
Chromatography: separating particles based on their interactions with a stationary phase.

Physical properties of matter include: mass, volume, density, buoyancy, solubility, and viscosity.
Mass: a measure of the amount of matter in an object.
Volume: a measure of the amount of space occupied by an object.
Density: the ratio of mass to volume.
Buoyancy: the ability of an object to float or sink in a fluid.
Solubility: the ability of a substance to dissolve in a solvent.
Viscosity: the resistance of a fluid to flow.