1. Properties of Matter

2. Physical properties Can be observed and measured without changing the kind of matter being studied. Physical changes do not change the substance, they change a physical property of the substance. The following physical properties can be used to help identify a substance:  Changes of state  Melting Point  Boiling Point  Density  Color  Mass  Volume

3. Density Density is a measure of the amount of matter present in a given volume of a substance. Substances that are denser contain more matter in a given volume. For any substance, the amount of mass in a unit of volume is constant. For different substances, the amount of mass in a unit of volume may differ.  Ex. Lifting a box of feathers compared to a box of pennies The density of a substance will stay the same no matter the size of the substance.

4. What is the formula for density? Density is normally expressed in units of grams per cubic centimeter (g/cm 3 ). Density = mass / volume  D= m/v

5. Let’s Try A Problem Together A glass marble has a volume of 5 cm 3 and a mass of 13 g. What is the density? What steps do we take?  Identify the correct formula  D= M/V  Volume = 5 cm 3  Mass = 13 g  Density = 13g / 5 cm 3  Density = 2.6  What is missing?  Correct Units  Density = 2.6 g/cm 3

6. Color Color can be used to help identify a substance, along with other properties. By itself color is not a significant identifier of a substance. Absence of color is also a physical property.

7. Melting Point Melting- the process by which a solid becomes a liquid. Melting Point- The temperature at which a solid can change to a liquid. The temperature at which a pure substance melts is unchanging under constant conditions. As solids heat up, their particles begin to gain energy and vibrate faster. When the temperature is high enough the particles of a solid will break a part and become a liquid. Not all melting points are the same! Ice melts to form liquid water at 0 º C (32 º F). Iron must be heated to 328°C (622°F ) to melt

8. Freezing Point Freezing- process by which a liquid becomes a solid. As temperature decreases, solid particles begin to move slower and have less energy. The temperature at which a specific liquid becomes a solid is called the freezing point. At the freezing point, the substance can act either as a liquid or a solid. Below the freezing point, the substance is a solid.

9. Evaporation The process by which a liquid becomes a gas. This normally occurs at the surface of the liquid. Not all particles in a liquid move at the same speed. Surface particles move faster than others below the surface and can break away from other molecules and become a gas. Involves a temperature increase

10. Sublimation Under certain conditions, solids can lose particles through a process similar to evaporation. When a solid changes directly to a gas, the process is called sublimation. Ex. Dry ice is frozen carbon dioxide (CO 2 ) that sublimates in normal atmospheric conditions.

11. Boiling Point The temperature at which a liquid boils. During the process of boiling a substance changes from a liquid to a gas. Boiling begins when the liquid starts to form bubbles throughout, which grow larger, rise to the surface, and burst. As long as the substance is boiling the temperature of the liquid remains constant (at the boiling point). Boiling point is unchanging under constant conditions for a given substance and therefore can be used as a physical property for identification of the substance. The boiling point for pure water at sea level is 100 º C or 212 º F.

12. Condensation The process by which a gas changes its state to become a liquid. As with evaporation, condensation can occur at a wide range of temperatures. Involves a temperature decrease  Ex. Beaded water on cold water glass  The cold glass cools the air surrounding it  When you cool a gas, the molecules lose energy and move slower  Changing the gas to a liquid.

13. Chemical Properties Chemical properties can also be used to help identify a substance. Chemical properties can be recognized only when substances react or do not react chemically with one another When they undergo a change in composition. A chemical property of one substance usually involves its ability to react (combine) or not react with another specific substance.

14. Chemical Changes Chemical Change- the change of one substance into another substance. Signs of a chemical change Production of an odor  Eggs rotting produce the smell of sulfur Change in temperature  Exothermic reactions- release heat (energy)  Exo- producing therm-heat  Endothermic reactions –absorb heat(energy  Endo-Within therm- heat Change in color  Ex. Fruit changing color when it ripens Formation of a precipitate (solid) Formation of bubbles

15. Chemical Changes The ability to burn The ability of a substance to burn is a chemical property that involves a substance reacting quickly with oxygen to produce light and heat. The ability to rust The ability of a substance to rust is a chemical property that involves a substance reacting slowly with oxygen.

16. Two examples of chemical properties include  The ability to burn  chemical property that involves a substance reacting quickly with oxygen to produce light and heat.  The ability to rust-  chemical property that involves a substance reacting slowly with oxygen.

17. Physical Changes vs. Chemical Changes What type of change occurs when you boil water? Physical What type of change occurs when an egg cooks? Chemical What type of change occurs when you cut your hair? Physical What type of change occurs when you burn leaves? Chemical What type of change occurs when a fence rusts? Chemical