Structure of Matter Review

Distinguish between atoms and molecules Atom: the smallest unit of an element that maintains the properties of that element (pg 312) Molecules: the smallest unit of a substance that keeps all of the physical and chemical properties of that substance (pg 373)

Explain the difference between pure substances and mixtures Pure substance: a sample of matter, either a single element or a single compound, that has definite chemical and physical properties (pg 90) Mixtures: a combination of two or more substances that are not chemically combined (98) Pure Substances and Mixtures Chem4Kids

Examples…

Recognize pure substances as elements or compounds Element: substance that cannot be separated or broken down into simpler substances by chemical means (90) Compound: a substance made up of atoms of two or more different elements joined by chemical bonds (94)

Describe the movement of particles in different states of matter, such as: Solid: the state of matter in which the volume and shape of a substance are fixed (67) Liquid: the state of matter that has a definite volume but not a definite shape (68) Gas: a form of matter that does not have a definite volume or shape (69) Plasma: form of matter that has little or no order

Recognize physical properties of matter, such as: Density: the ratio of the mass of a substance to the volume of the substance (pgs 26, 45) Melting point: the temperature at which a solid becomes a liquid by adding heat (pg 75) Boiling point: the temperature at which a liquid turns to a vapor by adding heat (pg 76) Changing States of Matter Chem 4 Kids

Recognize chemical properties of matter, such as: Reactivity: The rate at which a substance will undergo a chemical reaction with another substance Combustibility (Flammability): Measure of how easily a substance will burn

Distinguish between properties of matter as physical properties or chemical properties Physical properties : properties that do not change the chemical nature of matter Examples of physical properties are: color, smell, freezing point, boiling point, melting point, infra-red spectrum, attraction (paramagnetic) or repulsion (diamagnetic) to magnets, opacity, viscosity and density. There are many more examples. Note that measuring each of these properties will not alter the basic nature of the substance. Chemical properties : properties that change the chemical nature of matter Examples of chemical properties are: heat of combustion, reactivity with water, PH, and electromotive force. Matter is the Stuff Around You: Changes in Matter

PH: Base or Acid ReactivityCombustibility DensityViscosity Opacity Magnetism Melting PointBoiling Point Freezing Point Color

Differentiate between changes in matter as physical changes or chemical changes Physical changes: a change of matter from one form to another without a change in chemical properties (pg 48) Chemical changes: a change that occurs when one or more substances change into entirely new substances with different properties (pg 52) Chemical v Physical Changes

Recognize that more than 100 elements can be organized based on similar characteristics Periodic Table with Atomic Numbers

Explain that some elements have similar properties as shown on the Periodic Table of Elements, such as metals and nonmetals Interactive Periodic Table of Elements A zig zag line that starts between aluminum and boron and stair steps down, separates metals from non- metals. Everything to the left is a metal; to the right, non-metal.

Demonstrate an understanding of the Law of Conservation of Matter In any physical or chemical change, matter is neither created nor destroyed but merely changed from one form to another. Matter: Form & Substance in the Universe (18:44) Video