Chemistry J.P. Hancock, B.S., M.Ed Matter & Change Pt. 2 Chemistry J.P. Hancock, B.S., M.Ed

Matter Matter Mass Anything that has mass and takes up space The amount of substance in an object

Atom at a Glance The atom is the smallest particle of matter

Particles in the Atom Inside the nucleus Surrounding the nucleus Electrons-negative charge (e-) Inside the nucleus Protons-positive charge(p+) Neutrons-neutral charge

Particles in the Atom The number of protons is equal to the number of electrons in a neutral atom                             

Properties of Matter Hard or soft Flammable or non flammable Hot or cold Rough or smooth

Hard or Soft

How do atoms exist? Diatomic molecules Chlorine, Nitrogen, Oxygen, Fluorine, Hydrogen Alone or in pairs Diatomic molecules are two like atoms of the same element that will occur in pairs naturally

Types of Matter ELEMENTS COMPOUNDS MIXTURES Combination of one or more like atoms A substance that cannot be decomposed by a chemical change Combination of two or more elements joined to form a “new substance” whose properties are different from the individual elements A substance that can decompose into elements or compounds or both Combination of two or more substances that can be separated by physical means(stirred together but not chemically combined)

A Closer Look

Classification of Matter

Types of Mixtures Heterogeneous Homogeneous

HOMOGENEOUS Homogeneous Substances are evenly mixed                                                                        Homogeneous Substances are evenly mixed The particles are so small that they cannot be seen even with a microscope (1nm = 10-9) Never settle; remain constantly and uniformly mixed

HETEROGENEOUS Heterogeneous Substances are unevenly mixed and the different materials can be easily distinguished

Heterogeneous vs. Homogeneous

COLLOIDS & SUSPENSIONS Colloid is a heterogeneous mixture The particles will scatter light which is called the Tyndall Effect Suspension is a heterogeneous mixture containing a liquid with visible particles that settle

Changes in Matter

Physical Changes Changes in the form or appearance w/o making the substance a new substance. Ex chop wood, bend wire, melt ice All changes in the states of matter Solid Liquid Gas

Chemical Changes Changes that occur from the rearrangement of atoms into new combinations. Ex iron rusting, gasoline burning in a car engine

Representing Compounds Chemical symbol- 1-2 letters representing an element Chemical formula-ratio of elements in a compound

Mass The amount of matter an object contains SI unit is the kilogram 90 lbs = 40kg 1000g=1kg Nickel = 5 grams Baseball= 150 grams Med. Glass of water=200grams

Volume Volume is the amount of space matter occupies Volume Volume is the amount of space matter occupies. Solids, liquids, and gases all have volume

Density The amount of mass contained in a given volume Density = Mass D= M V SI Units g/cm3 for Solids g/ml for liquids

Sample Problem Calculations Volume = 25 cm3 D= m/v Mass = 20 g 20 grams = 0.8 g/cm3 25cm3

Solid Volume Solid volume= length x width x height (cm3) 100cm = 1m 1m3= 100cm x 100cm x 100 cm See page 28 for Common Conversion 1000ml = 1L