Matter Can Exist in Many States Can Be Made Up of Elements, Compounds, and Mixtures

Matter Anything that has density (mass and takes up space) Mass is a constant property unlike weight and volume Ex. Al, water, air, glass

Describing Matter –Extensive Properties –The mass of an object is a measure of the amount of matter the object contains. –The volume of an object is a measure of the space occupied by the object. –An extensive property is a property that depends on the amount of matter in a sample. 2.1

Describing Matter –Intensive Properties An intensive property is a property that depends on the type of matter in a sample, not the amount of matter. The hardness of a bowling ball is an example of an intensive property. 2.1

Divisions of Matter Pure Substance –All matter that has a uniform and definite composition and cannot be separated physically –ie elements and compounds –water, oxygen, sugar

Identifying Substances Matter that has a uniform and definite composition is called a substance. These kettles are mainly copper. Copper is an example of a substance. 2.1

Element: A substance that cannot be decomposed by any chemical reaction into simpler substances. Made up of atoms Compound: A substance made up of elements chemically combined to each other and can be decomposed by chemical means Are in a fixed proportion

Mixture Mixture (not a substance) –Combinations of two or more pure substances that are not chemically combined together can be separated by physical means ( not a fixed conposition) –Retains its individual properties –coffee ground, salt water

Classifying Mixtures A mixture is a physical blend of two or more components. A salad bar provides a range of items. Customers choose how much of each item to use in their salads. Each salad has a different composition. 2.2

Types of Mixtures Homogeneous –Material has a uniform composition throughout (particles are evenly mixed) Another name for a homogeneous mixture is a solution. Heterogeneous –Materials with varying composition (parts are not uniformly mixed or dispersed)

2.2 Classifying Mixtures When oil and vinegar are mixed they form layers, or phases. The oil phase floats on the water phase.

Types of Mixtures Variable combination of 2 or more pure substances. Heterogeneous – visibly separate phases Homogeneous – Same throughout

Identifying Substances A physical property is a quality or condition of a substance that can be observed or measured without changing the substance’s composition. Used in identification of the substance Hardness, color, conductivity, and malleability are examples of physical properties. Properties of metals –Ductile –Malleable –Conducts electricity 2.1

Identifying Substances 2.1

Chemical Properties Characteristic that describes how the substance interacts or fails to interact with other substances to produce a new substance 4Fe(s) + 3 O 2 (g) 2Fe 2 O 3 (s) Corrosion or rusting

States of Matter –Three states of matter are solid, liquid, and gas. 2.1

States of Matter –Solids A solid is a form of matter that has a definite shape and volume. Geometric shape Crystalline structure Strong Intermolecular forces (IMF) 2.1

States of Matter –Liquid A liquid is a form of matter that has an indefinite shape, flows, yet has a fixed volume. Intermediate IMF 2.1

States of Matter –Gases A gas is a form of matter that takes both the shape and volume of its container. Weak Intermolecular force Indefinite shape and volume 2.1

States of Matter Vapor describes the gaseous state of a substance that is generally a liquid or solid at room temperature, as in water vapor. H 2 0 (g) water vapor I 2 (g) Iodine vapor 2.1

Physical Changes During a physical change, some properties of a material change, but the composition of the material does not change. As gallium melts in a person’s hand, the shape of the sample changes, but the composition of the material does not change. 2.1

Physical Changes Physical changes can be classified as reversible or irreversible. All physical changes that involve a change from one state to another are reversible. Boiling, freezing, melting condensing Cutting hair, filing nails, and cracking an egg are examples of irreversible physical changes. 2.1

Distinguishing Elements and Compounds –Breaking Down Compounds A chemical change is a change that produces matter with a different composition than the original matter. When table sugar is heated, it goes through a series of chemical changes. 2.3

Distinguishing Elements and Compounds The final products of these chemical changes are solid carbon and water vapor. The following diagram summarizes the process. 2.3

Distinguishing Elements and Compounds –Compounds can be broken down into simpler substances by chemical means, but elements cannot. 2.3

Distinguishing Elements and Compounds Chlorine is used to kill harmful organisms in swimming pools. 2.3

Distinguishing Elements and Compounds Sodium is stored under oil to keep it from reacting with oxygen or water vapor in the air. Sodium vapor produces the light in some street lamps. 2.3

Distinguishing Elements and Compounds Sodium Chloride (commonly known as table salt) is used to season or preserve food. 2.3

Separating Mixtures –Filtration The process that separates a solid from the liquid in a heterogeneous mixture is called filtration. A colander is used to separate pasta from the water in which it was cooked. This process is a type of filtration. 2.2

Matter Flowchart MATTER Can it be physically separated? Homogeneous Mixture (solution) Heterogeneous MixtureCompound MIXTUREPURE SUBSTANCE yesno Can it be chemically decomposed? noyes Is the composition uniform? noyes Element

2.2 Separating Mixtures –How can mixtures be separated?

Separating Mixtures –Distillation During a distillation, a liquid is boiled to produce a vapor that is then condensed into a liquid. 2.2

Techniques Filtration Separation TechniquesSeparation Techniques Chromatography Distillation **used to separate solids dissolved in liquids **used to separate miscible liquids that have different boiling points distillationdistillation

Separation Techniques The following properties can be used to separate mixtures Density Molecular polarity Freezing point Boiling point

Law of Definite Proportions : A pure compound,whatever its source, always contains definite,or constant proportions of the elements by mass. Example 18g H 2 O 16gO 2 + 2gH 2 What if you have 36 g of water decomposed? How many grams of oxygen would be produced? 36g 32 g + 4 g

Law of Conversation of Matter In any physical or chemical reaction, mass is neither created nor destroyed; it is conserved 18g H2O 16gO2 + 2gH2

Separation of Mixtures into Substances Filtration Magnetic Separation Screening Distillation a. Salt solution b. Iron specks in sugar c. Salt and Sand d. Carbon in water

–1.Which of the following would be described as an extensive property of matter? temperature color mass hardness 2.1 Section Quiz.

Match the states of matter with the following descriptions: (1) takes the volume and shape of its container (2) has a definite shape and volume (3) has a definite volume but an indefinite shape (1) liquid, (2) solid and (3) gas (1) gas, (2) solid, and (3) liquid (1) gas, (2) liquid, and (3) solid