Ch.1-2 Properties of Matter

POINT > Define atoms, elements and compounds POINT > Distinguish between extensive and intensive properties of a substance POINT > Distinguish between physical and chemical properties of a substance POINT > Characterize three states of matter POINT > Define pure substances vs mixtures

POINT > Define atoms, elements and compounds Atoms are the fundamental building blocks of matter. An atom cannot be broken down into smaller units without losing its chemical identity

POINT > Define atoms, elements and compounds Atoms can differ from each other based on the number of protons, neutrons and electrons they have The different types of neutral atoms are called elements: carbon (C), hydrogen (H), gold (Au), oxygen (O), sulfur (S), sodium (Na), etc., are elements. All the elements are found in the Periodic Table Different elements have different numbers of protons

POINT > Define atoms, elements and compounds Compounds are substances made of atoms of two or more elements chemically bound to each other Water (H 2 O), salt (NaCl), glucose (C 6 H 12 O 6 ) and methane (CH 4 ) are examples of compounds A compound therefore can be broken down chemically into its constituent elements

WB CHECK: What is the difference between an element and a compound? What are atoms made of? What makes two elements different from each other?

POINT > Distinguish between extensive and intensive properties of a substance Extensive properties depend on how much of the substance is present. For example: Volume - how much space a substance occupies Mass - how much matter is present in a substance

POINT > Distinguish between extensive and intensive properties of a substance Intensive properties do not depend on how much of the substance is present. For example: Boiling and/or melting point Density (mass/volume) Color Hardness

WB CHECK: Copper is ductile; it can be made into wire. Is this an extensive or intensive property? A diamond weighs 10 carats. Is this an extensive or intensive property?

POINT > Distinguish between physical and chemical properties of a substance A physical property can be observed or measured without changing the substance’s composition This can include both extensive and intensive properties (hardness, color, boiling point, mass, etc) Physical changes are those that do not alter the identity of the substance. For example: cutting, grinding, melting, freezing, boiling

POINT > Distinguish between physical and chemical properties of a substance A chemical property is one that defines the ability of a substance to be transformed into another substance(s) in a chemical reaction For example, iron can rust Fe + O 2  Fe 2 O 3

POINT > Distinguish between physical and chemical properties of a substance Chemical changes can be indicated by: smoke, color change, odor change, bubbles (not boiling), formation of a new solid (not freezing), light emission

WB CHECK: Propane freezes at -188 ◦ C. Is this a physical or chemical property? You burnt your toast. Is this a physical or chemical change in the bread?

POINT > Characterize three states of matter Solids have a definite shape and definite volume. Solids are not easily compressed.

POINT > Characterize three states of matter Liquids have a definite volume, but no definite shape. They change shape to fit the container. Liquids are not easily compressed.

POINT > Characterize three states of matter Gases have no definite shape or volume. Gases conform to the shape of the container and expand to fill the container. Gases are easily compressed.

WB CHECK: A substance has a definite volume, but no definite shape. Is this a solid, liquid or gas? Which state(s) of matter cannot be easily compressed?

POINT > Characterize three states of matter Substances can change state, for example: melting - solid > liquid freezing - liquid > solid boiling - liquid > gas condensing - gas > liquid deposition - gas > solid sublimation - solid > gas These are physical changes, not chemical changes. The identity of the substance is not changed!

POINT > Define atoms, elements and compounds POINT > Distinguish between extensive and intensive properties of a substance POINT > Distinguish between physical and chemical properties of a substance POINT > Characterize three states of matter POINT > Define pure substances vs mixtures

Formative Assessment (F.A.) #1-3 page 14 Pre-read Section 1.3 pp.16-20