Matter and Change

1. Matter and Change 1.2 & 1.3 in your text book

2. 1.2 Matter and Its Properties • Matter- anything that has mass and takes up space. • Mass- a measure of the amount of matter in an object. • Volume- the amount of 3-dimensional space occupied by an object.

3. Basic Building Blocks of Matter • Atom- smallest unit of an element (same properties of the element). • Element- a pure substance made of only one kind of element. • Compound – substance made from 2 or more elements that are chemically bonded. Virus

4. Classification of Matter • Pure Substance- has a fixed composition: • Every sample of a given pure substance has exactly the same characteristic properties. • Every sample of a given pure substance has exactly the same composition. • A pure substance is matter with a fixed composition and definite properties. • EX: isopropanol. • Pure substances blend together to make mixtures.

5. Mixture- is a blend of 2 or more kinds of matter, each retains its identity and properties. Ex: grape juice shares the wetness of H2O and the sweetness of the sugar.*** • Heterogeneous mixtures: are mixtures that do not uniformly mix together. • Ex: flour and H2O. • Homogeneous mixtures: mix uniformly through out. • Ex: H2O & NaCl (table salt) or C6H12O6.

6. Properties & Changes in Matter Intensive properties- does NOT depend on amount of matter in substance. Melting point Boiling point Density Conductivity Heat conduction • Extensive properties – depends on amount of matter in substance. • Volume • Mass • Amount of energy

7. Physical Properties • Physical Property- a characteristic that can be observed or measured without changing the identity of the substance. • Melting point- temp. @ which a solid becomes a liquid. • Boiling point- temp. @ which a liquid becomes a gas. • Density - the mass per unit volume. • Buoyancy - the force with which a more dense fluid pushes a less dense substance upward. * These properties help determine the use of the compound. *

8. Physical Changes • Physical Change- a change in the substance that does not involve a change in the ID of the substance. • Ex: grinding, cutting, melting, boiling. • An important type of physical change is a change of state. • A physical change from one state to another There are 4 states of matter: solids, liquids, gases, and plasma. These states of matter are physically different.

9. Solid LEAST AMOUNT OF ENERGY • Solids have a definite volume and definite shape • Molecules do not move freely, they vibrate in place, giving solids a rigid structure. • They have ordered, fixed, and tightly packed arrangements due to chemical bonding and intramolecular interactions

10. Liquids • Liquids have definite volume but not definite shape • Molecules are closer together and moves faster than solids. • Molecules are weakly attracted to one another moving less freely than gas. They move randomly and fill the container in which they are held.

11. Gases • Gases have neither definite volume nor shape. • Molecules are in constant, random motion spreading out in all directions (diffusion). • They exert pressure. The pressure is made by individual gas molecules hitting the sides of the container.

12. Plasma • A high-temperature physical state of matter in which atoms lose their electrons. • Usually an ionized gas. • Does not have definite shape. • Conducts electricity well. • Effected by electric & magnetic fields.

13. Chemical Properties • A property of a substance related to it’s ability to undergo chemical changes, becoming a new/different substance. • Reactivity- the ability of a substance to react chemically with another substance. How much it will react depends on what they are reacting with and in what kind of environment the rxn is occurring. • Ex: rust (the ability of iron to react with oxygen), combustion/flammability, electronegativity, ionization potential, pH, heat of combustion, toxicity, stability…

14. Chemical Change • Chemical Changes: occurs when a substance changes composition to form a new substance. • Na2O + H2O→ 2NaOH • Combustion: • CH4 + 2O2→ CO2 + 2H2O

15. In a chemical reaction there are 2 types of substances: reactants and products. • The substance that enters into the reaction is the REACTANT. • The new substance(s) produced by the reactions is/are the PRODUCT(s). Ex. H2 + Cl2 → 2 HCl Reactants Products • On the REACTANTs side the + reads “reacts with” • On the PRODUCTs side the + reads “and” • The →reads “yields”, “forms” or “produces”

16. Energy & Changes in Matter • Energy’s Role: required to move or change matter. Energy is transferred in all changes of state. • Energy Required- to melt or evaporate any substance. • Energy Released - during condensation or freezing. Gas → Liquid or Liquid → solid.

17. 1.3 Elements • Introduction to the Periodic Table of Elements (PTofE). • Organizing the Squares: • When you look at the modern Periodic Table of Elements (PTE) you will notice it is arranged in to columns(vertically)and rows(horizontally). The columns are called GROUPS or FAMILIES(18). The rows are called PERIODS(7). Periods Groups

18. Types of Elements • Metals- an element which conducts electricity & heat well. • Properties of metals: • Most are solids • Malleable- able to be hammered/ rolled into sheets • Ductile- made into a wire • High Tensile Strength- resists breaking when pulled • Luster- the state or quality of shining by reflecting light; glitter, sparkle, sheen, or gloss

19. Nonmetals- an element which is a poor conductor of electricity and heat. • Many are gases at room temperature • Only Bromine is a liquid • Some are solids but they are brittle.

20. Metalloids- elements that have some characteristics of metals and some of nonmetals. • Are less malleable than metals but not as brittle as nonmetals. • Are semiconductors- conduct electricity better than nonmetals but not as well as metals.

21. Noble Gases- also known as the inert gases • Fairly nonreactive • Complete valence shell • High ionization energies • Very low electronegativities • Low boiling points (all gases at room temperature)