Classification of Matter

Matter Matter: Anything that has mass and volume (takes up space) 3 phases of matter

The Nature of Matter Chemists are interested in the nature of matter and how this is related to its atoms and molecules. GoldMercury

Chemistry & Matter We can explore the MACROSCOPIC world — what we can see — We can explore the MACROSCOPIC world — what we can see — to understand the PARTICULATE worlds we cannot see. to understand the PARTICULATE worlds we cannot see. We write SYMBOLS to describe these worlds. We write SYMBOLS to describe these worlds.

A Chemist’s View of Water H 2 O (gas, liquid, solid) MacroscopicMacroscopic SymbolicSymbolic ParticulateParticulate

A Chemist’s View 2 H 2 (g) + O 2 (g) --> 2 H 2 O(g) MacroscopicMacroscopic SymbolicSymbolic ParticulateParticulate

Kinetic Nature of Matter Matter consists of atoms and molecules in motion.

STATES OF MATTER Solids — have rigid shape, fixed volume. External shape can reflect the atomic and molecular arrangement. Solids — have rigid shape, fixed volume. External shape can reflect the atomic and molecular arrangement. Liquids — have no fixed shape and may not fill a container completely. Liquids — have no fixed shape and may not fill a container completely. Gases — expand to fill their container. Gases — expand to fill their container.

OTHER STATES OF MATTER PLASMA — an electrically charged gas; Example: the sun or any other star PLASMA — an electrically charged gas; Example: the sun or any other star BOSE-EINSTEIN CONDENSATE — a condensate that forms near absolute zero that has superconductive properties; Example: supercooled Rb gas BOSE-EINSTEIN CONDENSATE — a condensate that forms near absolute zero that has superconductive properties; Example: supercooled Rb gas

Physical Properties – Characteristic of a substance that can be observed (using your senses) without changing the substance into something else. Physical properties are used to identify, describe and classify matter. HardnessTextureColor OdorTasteTemperature

More EXAMPLES - Physical size, shape, freezing point, boiling point, melting point, magnetism, viscosity, density, luster and many more. – Viscosity - The resistance of a liquid to flowing. – Examples: – Low viscosity-water, rubbing alcohol – High viscosity-honey

Physical Changes – can be observed without changing the identity of the substance Some physical changes would be boiling of a liquid boiling of a liquid melting of a solid melting of a solid dissolving a solid in a liquid to give a homogeneous mixture — a SOLUTION. dissolving a solid in a liquid to give a homogeneous mixture — a SOLUTION.

Physical Changes can be Reversible include melting, freezing, boiling, condensing, and evaporating. Irreversible include breaking, splitting, grinding, crushing, and cutting.

Intensive/Extensive Properties extensive property - a property that depends on the amount of matter in a sample. Mass and volume are examples of extensive properties. intensive property - a property that depends on the type of matter in a sample, not the amount of matter. Every sample of a pure substance has identical intensive properties because every sample has the same composition. Hardness, color, conductivity, density and malleability are examples of intensive properties.

Chemical Properties Chemical properties are characteristics involved when a substance interacts with another substance to change its chemical make-up. FlammabilityRustingCreating gas bubbles Creating a new chemical product Reactivity with water pH

Chemical Change Chemical change or chemical reaction — transformation of one or more atoms or molecules into one or more different molecules.Chemical change or chemical reaction — transformation of one or more atoms or molecules into one or more different molecules. Burning hydrogen (H 2 ) in oxygen (O 2 ) gives H 2 O.Burning hydrogen (H 2 ) in oxygen (O 2 ) gives H 2 O.

Possible Signs of a Chemical Change Heat- exothermic if given off, endothermic if taken inHeat- exothermic if given off, endothermic if taken in LightLight Gas Produced (not from boiling!)Gas Produced (not from boiling!) Precipitate – a solid formed by mixing two liquids togetherPrecipitate – a solid formed by mixing two liquids together Color Change (sometimes)Color Change (sometimes)

A. Physical vs B. Chemical Examples: – melting point – flammability – density – magnetic – tarnishes in air physical chemical physical chemical

A. Physical vs B. Chemical Examples: – rusting iron – dissolving in water – burning a log – melting ice – grinding spices chemical physical chemical physical

Classification of Matter Now that we have defined chemical and physical properties of matter, we can use that to help us classify it. One way chemists classify matter is based on its purity.

Matter Mixture Pure Substance Element Compound Heterogeneous Mixture Homogeneous Mixture Can be separated physically Cannot be separated physically Can see the parts Cannot see the parts Can be separated chemically Cannot be separated Most impureMost pure suspensioncolloid

Classification of Matter Pure Substance – Matter that has only 1 set of chemical and physical properties. Example: Pure water always has the exact same chemical and physical properties under the same conditions. If water ever tastes different then it isn’t pure water; it fits into our next category.

Classification of Matter Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. Example: Copper and Zinc can be mixed together to produce brass. Even though it may look different, it is still copper and zinc. Each metal retains its own properties like melting point.

Classification of Matter Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. Unlike pure substances, mixtures can always be separated by physical means. How could we separate the copper and zinc back out?

Mixtures Mixture – Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. If a sample of sand contains iron and salt, how could you separate them from the other minerals?

Mixtures Some mixtures are more pure than others. Heterogeneous mixture – Uneven distribution of substances. (Very impure) - You can see the different parts. Examples: Sand Granite Wood

Mixtures Some mixtures are more pure than others. Heterogeneous mixture – Uneven distribution of substances. (Very impure) - You can see the different parts. Examples: Milk Blood

Mixtures Homogeneous Mixture – Components are evenly mixed. (More pure than heterogeneous) Salt water contains salt and water, but are mixed all the way to the atomic level - Cannot see the parts., but it can still be separated by physical means. Seawater distillation plant

Pure Substances Pure substances can also be divided into 2 categories: compounds and elements.

Pure Substances Compound – Two or more elements chemically bonded together. Examples: Carbon Dioxide (CO 2 ) Water (H 2 O) Salt (NaCl) Sucrose (C 12 H 22 O 11 )

Pure Substances Compounds have only 1 set of properties. They cannot be separated by any physical process. - Can only be separated by a chemical reaction. Water can be separated into Hydrogen and Oxygen by a process called Electrolysis.

Pure Substances Elements – Substances made up of only one type of atom. - Cannot be separated by any physical OR chemical process. Examples: Carbon Helium Gold

Matter Mixture Pure Substance Element Compound Heterogeneous Mixture Homogeneous Mixture Can be separated physically Cannot be separated physically Can see the parts Cannot see the parts Can be separated chemically Cannot be separated Most impure Most pure

Classify the following slide using these five classifications: - Non-matter - Heterogeneous Mixture - Homogeneous Mixture - Compound - Element

Helium He Bronze Cu + Sn Electricity Steel Fe + C Water H 2 O Cookie Air N 2 + O 2 + Ar + CO 2 Carbon Dioxide CO 2 Italian Dressing Iron Fe Salt Water H 2 O + NaCl Diamond C Heat Light Mercury Hg