Notes: Chapter 2 Matter 2.1 What is Matter?Chemistry the study of matter and how it changesA. Matter anything that has mass and occupies space1. All matter is made of atoms. a. atom the smallest particle that has the properties of an elementb. element a substance that cannot be broken down into simpler substances2. Atoms combine to form compounds.compound a substance made of atoms of more than one element bound together. A compound does not have the characteristics of the two or more atoms that make up its composition. It is an entirely new thing.Ex: oxygen (gas) and hydrogen (gas) form water (liquid)3. Combinations of atoms also form molecules.Molecule the smallest unit of a substance that exhibits all of the properties characteristic of that substanceB. Pure Substance or Mixture?1. Pure substance matter that has fixed composition and definite properties, such as:a. elementb. compound2. Mixture a combination of more than one pure substance. A mixture has a combination of the properties of the two or more substances that make up its composition. Types of mixtures:a. homogeneous, also called a solution substances are evenly mixedb. heterogeneous substances arent evenly mixed 2.2 Matter and EnergyA. Kinetic Theory1. All matter is made of atoms and molecules that act like tiny particles2. These tiny particles are always in motion. The higher the temperature, the faster the particles move.3. At the same temperature, more massive (heavier) particles move slower than less massive (lighter) particles.B. States of Matter1. Solid rigid structurea. tightly packed atomsb. defined volume and defined shape2. Liquid fluid structurea. atoms are close, but not packedb. defined volume, but undefined shape* viscosity is the resistance of a fluid to flow; ex: honey has higher viscosity than water3. Gas fluid structurea. atoms are spread apartb. undefined volume and undefined shapeC. Energys Effect on States of MatterEnergy the ability to change or move matter1. Energy is transferred (absorbed or released) during every change of statea. melting and evaporating absorb energyi. heat of fusion amount of energy required to change a solid to a liquidii. heat of vaporization amount of energy required to change a liquid to a gasb. freezing and condensing release energy2. Changing state does not change composition or mass3. The law of conservation of mass: Mass cannot be created or destroyed.4. The law of conservation of energy: Energy cannot be created or destroyed. 2.3 Properties of MatterA. Chemical and Physical Properties1. Chemical Property the way a substance reacts with others to form new substances with different properties. This is called reactivity the ability of a substance to combine chemically with another substance. Examples of reactivity:a. flammability describes whether substances will react in the presence of oxygen and burn when exposed to a flame.b. pH a measure of the hydronium ion concentration in a solution (how acidic or basic something is)2. Physical Property a characteristic of a substance that can be observed or measured without changing the composition of the substance. Physical properties are -a. observable by the five senses, such as: color, odor, shape, textureb. testable without changing the substance, such as: density*, magnetism, boiling point, and the ability to conduct electricity.* Density the mass per unit volume of a substance; D = m/V; units for density = g/mLB. Chemical and Physical Changes1. Chemical Change a change that occurs when a substance changes composition by forming one or more new substances. Chemical change = chemical reaction2. Physical Change a change in the physical form or properties of a substance that occurs without a change in composition; the substance may look different, but the atoms that make up the substance are not changed or rearranged.