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Matter & Change

Chemistry: the study of matter and changes that are associated with it. ex: physical and/or chemical

Properties of Matter: matter is anything that has mass and occupies space.

5 Indicators of a Chemical Change:

  • emission of light and/or heat

  • formation of a gas

  • formation of a precipitate

  • change in color

  • emission of odor

All matter can be classified into three groups:

  • elements

  • compounds

  • mixtures

States of Matter:

Solid

  • has a definite volume and shape

  • the particles of a solid are packed close together in relatively fixed positions

  • particles are held by very strong forces between them

  • the particles of a solid simply vibrate about a fixed position

Liquid

  • has a definite volume but no definite shape

  • assumes the shape of the container

  • the particles of a liquid are held close together but because they are moving faster they can overcome the attractive forces and move one another

Gas/Plasma

  • has neither a definite shape nor definite volume

  • composed of particles that move very rapidly and are at a great distance from one another, making the attractive forces between the particles very weak

  • plasma: a high-temperature physical state of matter in which atoms lose most of their electrons

  • can be found in lightning, stars, and some TV screens

Endothermic vs Exothermic

Endothermic

definition: a reaction that releases energy to the surroundings, causing the reaction mixture and its surroundings to become hotter

examples: burning/combustion, neutralization, and displacement

Exothermic

definition: a reaction in which energy is absorbed from the surroundings, causing the reaction mixture and its surroundings to become cooler

examples: evaporating or melting

Matter & Change

Chemistry: the study of matter and changes that are associated with it. ex: physical and/or chemical

Properties of Matter: matter is anything that has mass and occupies space.

5 Indicators of a Chemical Change:

  • emission of light and/or heat

  • formation of a gas

  • formation of a precipitate

  • change in color

  • emission of odor

All matter can be classified into three groups:

  • elements

  • compounds

  • mixtures

States of Matter:

Solid

  • has a definite volume and shape

  • the particles of a solid are packed close together in relatively fixed positions

  • particles are held by very strong forces between them

  • the particles of a solid simply vibrate about a fixed position

Liquid

  • has a definite volume but no definite shape

  • assumes the shape of the container

  • the particles of a liquid are held close together but because they are moving faster they can overcome the attractive forces and move one another

Gas/Plasma

  • has neither a definite shape nor definite volume

  • composed of particles that move very rapidly and are at a great distance from one another, making the attractive forces between the particles very weak

  • plasma: a high-temperature physical state of matter in which atoms lose most of their electrons

  • can be found in lightning, stars, and some TV screens

Endothermic vs Exothermic

Endothermic

definition: a reaction that releases energy to the surroundings, causing the reaction mixture and its surroundings to become hotter

examples: burning/combustion, neutralization, and displacement

Exothermic

definition: a reaction in which energy is absorbed from the surroundings, causing the reaction mixture and its surroundings to become cooler

examples: evaporating or melting