Chapter 2: Matter and Change

Notes overview Learn how to classify matter: By composition By state Identify properties of matter Learn how to separate substances Differentiate between changing substances chemically and physically

Properties of matter Extensive Properties Intensive Properties depends on the amount of matter present in a sample Examples: mass, volume Intensive Properties depends on the type of matter (not amount) Examples: hardness, density

The physical side of matter Physical Property quality or condition of a substance that can be observed without changing the substance’s identity (composition) Examples: hardness, color, conductivity, malleability, ductility, melting point, boiling point, state Physical Change changing the form of a substance without changing the identity (composition) properties remain the same

The chemical side of matter Chemical Property ability of a substance to undergo changes in identity (composition) through chemical reaction Chemical Change change that produces matter with a different identity (composition) than the original matter Products have different properties Examples: burning, rusting, fermenting, decomposing

Classifying matter by composition The focus is on the type and amounts of atoms present as well as how they are combined in the substance Two main types are: Pure Substances Mixtures

Types of mixtures flowchart MATTER yes no Can it be physically separated? MIXTURE Is the composition uniform? no yes Homogeneous Mixture (solution) Heterogeneous Mixture (suspension)

Mixtures Mixtures Are physical combinations of different substances Composition can vary (the proportions are not fixed) Can be separated into original parts using physical changes

Mixtures Homogeneous Mixture has a uniform composition will not settle out also called a solution Examples: salt water, Kool-Aid, air, steel, etc.

Mixtures Heterogeneous Mixture composition is not uniform will settle out also called a suspension Examples: blood, orange juice, mud puddle, salad dressing, bird seed, etc.

Mixtures Colloids (special type of heterogeneous mix.) Particles are intermediate in size… larger than those in a solution and smaller than those in a suspension will not settle out particles cannot be filtered can be distinguished by Tyndall effect where visible light is scattered (solutions don’t do this) Examples: Jello, whipped cream, marshmallow, milk, smoke, etc.

What type of mixture is shown?

What type of mixture is shown?

What type of mixture is shown?

What type of mixture is shown?

Ways to separate mixtures Separating mixtures is just problem-solving… One looks at the different physical properties of the substances in a mixture and selects one that is different Examples: distillation, filtration, decantation, evaporation, chromatography, centrifugation, electrophoresis

Distillation Purpose: used when boiling points differ between substances in a mixture Process: liquid mixture is boiled to produce a vapor which is collected and condensed back into a simpler liquid

Filtration Purpose: used when mixtures consist of liquids and solids together Process: solid/liquid mixture is poured through a screen or filter to catch the solid particles while the liquid flows past

Types of pure substances flowchart MATTER yes no Can it be physically separated? PURE SUBSTANCE Can it be chemically decomposed? no yes Compound Element

Pure substances Pure Substances Composition consists of atoms in fixed proportions Example: Water is H2O. It always has 2 hydrogens attached to 1 oxygen. Cannot be broken down into simpler substances physically

Pure substances Elements simplest form of matter consists of one type of atom only substances on the periodic table Example: gold (Au), aluminum (Al), carbon (C), etc.

Pure substances Compounds contains two or more elements chemically combined is in fixed proportions (can be shown with a chemical formula) cannot be broken down into simpler substances physically Examples: H2O (water), NaCl (table salt), C6H12O6 (sugar), etc.

Ways to separate pure substances To separate, chemical reactions must occur through a change in energy caused by chemical interactions, electricity, heat exchange, etc. Example: Electrolysis of water Direct current is applied to water (H2O) causing it to split into separate hydrogen atoms and oxygen atoms.

Types of matter flowchart yes no Can it be physically separated? MIXTURE PURE SUBSTANCE Is the composition uniform? no yes Can it be chemically decomposed? no yes Homogeneous Mixture (solution) Heterogeneous Mixture (suspension) Compound Element

Classifying matter by state The focus is on the arrangement of atoms in a particular substance 4 main states of matter are: solid liquid gas plasma 2 other states include Bose-Einstein condensate and fermionic condensate

Solids Definite shape Definite volume Not easily compressed

Liquids Indefinite shape (it can flow) Definite Volume Not easily compressed

Gases Indefinite shape Indefinite volume Easily compressed

Plasma Indefinite shape Indefinite volume Particles become ionized (positive and negative charges) which allows electricity to flow through them