What is chemistry? The study of matter and the changes it undergoes

Properties of Matter Matter is anything that has mass and volume (takes up space) Most everything is made of matter

What is mass? Mass is the amount of matter in an object Mass is constant

Mass vs. Weight The measure of the force of gravity on the mass of an object Weight changes with gravity

Properties of Matter Characteristics used to describe an object Physical Property A condition of a substance that can be observed or measured without changing the substance’s composition. Ex: color, luster, hardness A physical change involves the changing of physical properties (such as appearance or state) However, the composition or type of matter does NOT change

Intensive versus Extensive Intensive properties are independent of amount (stays the same no matter how much you have) Ex. color, boiling point Extensive properties change with amount Ex. length, mass

Phase Changes Phase changes can involve a change in volume, but mass remains constant. Adding or removing energy (or heat) from matter results in phase changes What are some examples of phase changes?

Properties of Matter (cont.) Chemical Property Property that describes how a substance can change into a NEW substance Ex: flammability, reactivity with water/oxygen During a chemical change, the original substance is converted into a new and different substance What is another name for a chemical change?

How is a chemical change different from a physical change?

States of matter Solid- matter that can not flow (definite shape) and has definite volume. Liquid- definite volume but takes the shape of its container (flows). Gas- a substance without definite volume or shape and can flow. Vapor- a substance that is currently a gas, but normally is a liquid or solid at room temperature.

Classification of Matter A mixture is a combination of two or more substance that can be separated by physical means Matter that cannot be separated physically is called a pure substance (needs to be chemically separated)

(Pure) Substances: element or compound Elements simplest kind of matter all one kind of atom Compounds substances that can be broken down only by chemical methods when broken down, the pieces have completely different properties than the original compound made of two or more atoms,chemically combined (not just a physical blend!)

Mixtures A physical blend of at least two substances Variable composition Heterogeneous – the mixture is NOT uniform in composition Homogeneous - same composition throughout Also called “solutions”

Periodic Table Elements: 1 or two letter symbol First letter always capitalized; if there is a second letter, it is lowercase Ex. B, Ba, C, Ca, H, He Compounds have a formula Ex. NaCl, CaSO4 , H2O Columns = Groups (families) Rows = Periods

Classification of Elements Elements can be classified as: Metals Located to the left of the “zigzag” line Nonmetals Located to the right Metalloids Located directly above or below the “zigzag” line