Physical Changes Physical changes only involve changes in state or appearance. What are some examples of physical change?
Catch words for Physical Change Boil •Split Freeze •Grind Melt •Cut Condense •Crush Break •Bend
Chemical Changes Chemical changes and chemical properties always produce new substances.
Chemical or physical change ??? Food spoiling Chemical Nail rusting Chemical Oil burning Chemical Sugar dissolving Physical Water boiling Physical Firefly flashing Chemical Egg cooking Chemical Snowflake melting Physical
Pure Substances Elements are the building blocks of matter. Atoms are the smallest part of an element.
Mixtures … do not have a definite composition … are either heterogeneous, with clearly visible components … or homogeneous, which are uniform in appearance
Solutions Solutions are homogeneous mixtures containing a solute which is dissolved in a solvent.
What is density?Density is the ratio of m the mass of an object D= to the volume of the object. V Typical units of density are grams per milliliter, g/mL
Density calculations A student determines that a piece of an unknown material has a mass of 5.854 g and a volume of 7.57 cm3. What is the density of the material, rounded to the correct number of significant digits? D= m/v D= 5.854g/7.57 cm3 D= .77 g/cm3