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Unit 2

Chapter Overview
During this unit, students review and extend their understanding of the physical and chemical properties of matter, as manifested in elements, compounds,
and mixtures.

Main Ideas
Analysis of the relationships between physical and chemical changes and properties is essential to understanding the nature of matter.
    *How are the properties of matter distinguished?
    *Why is the investigation and analysis of matter essential to the study of chemistry?
    *In what ways are properties used to classify matter?
    *How are changes in matter analyzed?

***Students may think mass and weight are the same, rather than understanding that mass is the amount of matter in an object or substance and weight is a
measure of the force of gravity on that matter or substance.
***Students may think a single observable change in properties, such as heat being given off or absorbed, is enough to indicate a chemical change.
***Students may think objects with larger volumes always have more mass.
***Students may think air and other gases do not have mass or weight.
***Students may not understand mass-volume relationships (density) as well as measuring and calculating density.
***Students may not understand that a sample of matter is either a pure substance or a mixture of pure substances.
Matter – anything that has mass and takes up space
Structure – arrangement of bonds between atoms in a molecule
Pure Substance – substances that are made of only one type of atom or only one type of molecule  
Element – substance that cannot be broken down into simpler substances by chemical means
Molecule – a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
Compound – a substance formed when two or more chemical elements are chemically bonded together
Mixture – substance made of two or more different substances that are mixed but are not chemically combined
Solution – mixture with two or more substances
Decant – separation of mixtures by removing a layer of liquid
Distillation – separating the parts of a liquid by boiling it and then condensing the vapor that results
Filtration – separation of solids from fluids by adding a medium through which only the fluid can pass
Physical Property – a characteristic of a pure substance that can be observed or measured without changing the substance’s chemical identity
Extensive Property – a physical property that depends on the amount of matter present
Intensive Property – a physical property that does not depend on the amount of the substance present
Compressibility – the measure of how much a given volume of matter decreases when placed under pressure
Density – the ration between mass and volume (d=m/v)
Ductility – physical property of a material associated with the ability to be drawn into a wire
Elasticity – physical property of a material where the material returns to its original shape after being deformed
Malleability – physical property of a material associated with the ability to be hammered thin into a sheet
Viscosity – a liquid’s resistance to flow
Volume – amount of space occupied by a substance
Physical Change – a change that alters a substance without changing its chemical composition or its identity
Evaporation – process of a substance in liquid state changing to a gaseous state
Sublimation – substance changes from a solid to a gas without passing through the liquid phase
Vaporization – substance changes from the liquid to gaseous state
Chemical Property – a characteristic of a pure substance that describes how it interacts with other substances
Chemical Change – a change in the chemical composition and the identity of a substance
Reactivity – tendency of a substance to undergo chemical changes
Solubility – degree to which a substance dissolves in a solvent to make a solution


Other Valuable Resources

Properties of Water

Phases of Matter

Matter Crash Course