MATTER

1. MATTER

2. matter • Chemistry is the study of matter and the changes that it undergoes. • Matter is anything that has mass and and volume. • Mass is a measurement that reflects the amount of matter. • Volume is a measurement that reflects the amount of space filled.

3. The atom • All matter is composed of atoms. • Atoms are made up of protons, neutrons, and electrons.

4. STATES OF MATTER • Matter that exists on Earth can be classified as one of the three physical forms, known as the States of Matter: • Solid – Definite shape & Definite volume • Definite (for both shape and volume) means that the container makes no difference whatsoever. • Liquid – Indefinite shape & Definite volume • Indefinite shape means that the sample takes on the shape of the container. • Gas – Indefinite shape & indefinite volume • Indefinite volume means the sample would expand to fill the entire container. Only gases do this.

5. SHAPE & VOLUME OF MATTER

6. MATTER CAN CHANGE STATES • Matter can change states when energy is added or removed. • For example: • As ICE, a solid, is heated, it is converted into a liquid, known as WATER. • As WATER, a liquid, is heated, it is converted into a gas, known as STEAM. • And the opposite when cooled.

7. Classification of matter • Matter can be further classified into two categories: • Pure Substances and Mixtures • Pure Substances can be further classified into two categories: • Elements and Compounds • Mixtures can be further classified into two categories: • Homogeneous mixtures and Heterogeneous mixtures

8. Classification of matter

9. Pure substances • Pure Substances can be classifiedinto two categories: • Elements and Compounds • Pure Substances always have the same composition. This is known as the Law of Constant Composition. • For example: • The compound water is alwayscomposed of • 2 Hydrogen atoms and 1 Oxygen atom

10. elements • Elements contain only one type of atom. • For example: • The element gold is only made of gold atoms.

11. Diatomic elements • Some elements only exist in nature as diatomic elements. • This means that they have 2 atoms of one element bonded together. • These 7 elements are H, N, O, F, Cl, Br, & I

12. compounds • Compounds contain two or more different types of atoms bound together in a particular way. • For example: • The compound carbon dioxide is made of • one carbon atom and two oxygen atoms.

13. Classification of matter

14. mixtures • A mixtureis a combination of two or more pure substances in which each pure substance retains (keeps) its individual chemical properties. It is a combination of elements and compounds. • A mixturehas variablecomposition. • For example: • In a mixture of ocean water collected at the beach, • there is salt, water, and sand. • Mixtures can be separatedphysically by filtration & distillation. • Mixtures can be further classified into two categories: • Homogeneous mixtures and Heterogeneous mixtures

15. HOMOGENEOUS MIXTURES • Homogeneous mixtures have the sameconsistency throughout. • Homogeneous mixtures can either be a solutionor an alloy. • Solutions may contain solids, liquids, or gases. • Alloys are a mixture of metals.

16. SOLUTIONS • Solutions may contain solids, liquids, or gases. • For example: AIR • A mixture of gases: Helium (He), Nitrogen (N2), Oxygen (O2), Neon (Ne), Water vapor (H2O), Carbon dioxide (CO2), & Argon (Ar) • For example: Coca-Cola • A mixture of gas & liquid: carbon dioxide (CO2) and soda. • For example: Salt water • A mixture of liquid & solid: water (H2O) and salt (NaCl)

17. alloys • Alloys are a mixture of two metals or a metal and a nonmetal. • For example: Brass • A mixture of two metals: zinc and copper • For Example: Steel • A mixture of a metal and a nonmetal: iron and carbon

18. Physical properties of matter • A physical property of matter can be observed or measuredwithoutchanging the sample’s composition. • Observations usually consist of some type of numerical measurement (quantitative) although sometimes there is a characteristic (qualitative description) of the property. • Groups of similar elements & compounds can be characterized by the physical properties that they have in common. • Examples: Color, odor, volume, state (solid, liquid, gas), luster (shiny), density, solubility, melting point, boiling point, electrical conductivity, malleability, and ductility (ability to form wires)

19. Chemical propertiesof matter • A chemical property of matteris the ability of a substance to combine with or change into a new substances. • Examples: Flammability (burning), rusting, digestion, growth, fermentation, combustion, neutralization

20. PHYSICAL CHANGES • A physical change alters a substance withoutchanging its composition. • The most common physical changes are those that involve a state change: • Solid  Liquid (melting, fusion), Liquid Gas (boiling, evaporation) • Solid Gas (sublimation) - Example: Dry ice • Gas  Solid (deposition) - Example: Frost • Gas  Liquid (condensation), Liquid Solid (freezing) • Other examples of physical changes are: • Grindingsomething into powder, chopping wood, etc.

21. Chemical changes • A chemical changeinvolves one or more substances changing into a new substance. • A chemical changemeans that the reacting compound(s) are changed into new compounds or products. • A chemical changeobeys the Law of Conservation of Mass because matter is neither created nor destroyed, just rearranged. The actual atoms involved remain, but they are rearranged into the new compounds. • The rearrangement is called a chemical reaction. • A chemical changeis a process in which chemical bonds are broken and new ones are made. • Chemical changes are called REACTIONS.

22. Chemical changes • Examples: • Silver tarnishing, a plant growing a leaf, • electrolysis (the splitting of a water molecule), combustion, iron rusting