Matter: Properties and Changes

1. Matter: Properties and Changes How can we classify Matter?

2. Matter • Is anything that has mass and takes up space • Is the measure of the amount of matter in an object • All material or “ stuff “ around us is matter

3. Properties of Matter • The characteristics that are used to identify matter and distinguish them from one another are called properties. These properties are grouped into two broad categories: physical propertiesand chemical properties.

4. Physical Properties • Physical propertiesof matter are usually those that can be observed with the senses. • It identifies the substance without causing a change in the composition of the substance.

5. Substance • Matter that has uniform and unchanging composition • Ex: H20 is a pure substance and no matter where it is found it will have the same composition as any other sample of water

6. Intensive Property • Property that remains the same no matter how much of a substance you have. • Ex: Density, MP, BP

7. Extensive Property • Property that is dependent on the amount of substance present. • Ex: mass, length, volume

8. Some Examples of Physical Properties • physical state (solid, liquid or gas at certain temperatures and pressures) • color, odor, size, shape, volume, • melting point or boiling point • hardness (or softness) • solubility - the ability of substance to dissolve • density – mass/volume • ductility – the ability to be drawn into a thin wire • malleability - the ability to be hammered into a thin sheet • conductivity – can conduct heat and/or electricity • flexible, brittle, volatile, lustrous (shine)

9. Examples of Physical Properties Sulfur is yellow & brittle. Metals are malleable. What does that mean? Look at your notes from the last slide.

10. Chemical Properties Chemical properties of matter are those that relate to • how the substance changes in composition • how it interacts with other substances. • Basically, the ability or inability of a substance to combine with or change into other substances There really isn't a set of chemical properties in the same way there is, more or less, a set of physical properties. That's because the chemical properties are tied to the change.

11. Some Examples of Chemical Properties • Flammability • Iron reacts with oxygen to form rust • Glucose, mixed with yeast, ferments to make alcohol and carbon dioxide • Combustibility • Copper forms copper carbonate (Patina) when in contact with moist air • Inability of gold to combine with other substances

12. Practice Problems Label - Physical or Chemical Property Silver tarnishes when it comes into contact with hydrogen sulfide in the air. A sheet of copper can be pounded into a bowl Barium melted at 725oC Helium does not react with any other element

13. Practice Problems 5. A bar of lead is more easily bent than is a bar of aluminum of the same size 6. Potassium metal is kept submerged in oil to prevent contact with oxygen or water 7. Diamond dust can be used to cut or grind most other materials 8. Rocks containing carbonates can be identified because they fizz when hydrochloric acid is applied

14. Answers to Practice Problems • Chemical • Physical • Physical • Chemical • Physical • Chemical • Physical • Chemical

15. Matter can also be classified as • A Physical change or • A Chemical change

16. Physical Changes Physical changes are those changes that do not result in the production of a new substance or do not alter the composition of the matter. • If you melt a block of ice, you still have H2O at the end of the change.  • If you break a bottle, you still have glass.  • Painting a piece of wood will not make it stop being wood. 

17. Examples of Physical Changes Some common examples of physical changes are • Changes of state: melting, freezing, condensing, boiling • Breaking • Crushing • Cutting • Bending

18. Chemical Changes Chemical changes, or chemical reactions, are changes that result in the production of new substances. • When you burn a log in a fireplace, you are carrying out a chemical reaction that releases carbon.  • When you light your Bunsen burner in lab, you are carrying out a chemical reaction that produces water and carbon dioxide. 

19. Chemical Changes • Also known as a chemical reaction • In a chemical reaction the starting substances are known as the reactants and the substances formed are called the products. • 2H2 + O2→ 2H2O (Reactants) (Product) • A chemical reaction shows the relationship between the reactants and products

20. Examples of Chemical Changes Common examples of chemical changes that you may be familiar with are • digestion • respiration • photosynthesis • burning • decomposition 

21. Practice ProblemsLabel - Physical or Chemical Change • Moisture in the air forms beads of water on a cold window pane • An electrical current changes water into hydrogen and oxygen • Yeast cells in bread dough make carbon dioxide and ethanol from sugar • Olive oil, vinegar, salt and pepper are shaken together to make salad dressing • Molten bronze is poured into a mold and solidifies to form a figurine • A reactant decomposes to form two products

22. Answers to Practice Problems • Physical • Chemical • Chemical • Physical • Physical • Chemical

23. The End