What is Chemistry?. Learning Objectives What is chemistry? What are the building blocks of matter?...
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Transcript of What is Chemistry?. Learning Objectives What is chemistry? What are the building blocks of matter?...
What is Chemistry?
Learning Objectives
What is chemistry?What are the building blocks of
matter?How does matter interact?How is matter organized?
What is Chemistry?
The study of the composition of matter and the changes that matter undergoes
It affects all aspects of life and non-living objects too
Chemistry explains things that we observe in the world around us
For example: the changing of the leaves in fall
Matter
Is anything that has mass and occupies space
It doesn’t have to be visible For example: humans, air, water, your
table & plants What isn’t matter? Light, heat, sound, electricity &
gravity
Phases of Matter
Three main phases: Solid Liquid Gas
What is the 4th state of matter and where is it found?
Elements
Are the simplest form of matter 114 elements have been identified Different elements combine to form
compounds
The Periodic Table
Periodic Table
Atom
Is the simplest particle of an element that retains all the properties of that element
They are too small to observe directly
So we use a model
Atom Model
The Nucleus
Located in the middle of an atom Made up of 2 subatomic particles:
Protons-have a positive charge
Neutrons-have no charge
Atomic Number, Atomic Mass,& Mass Number
The number of protons in an atom determines the atomic number of the element
The atomic mass is the average mass of the atoms in the element
The mass number an atom is the total number of protons & neutrons
Electrons
Balance out the number of protons with negative charges
They are very high energy and have very little mass
They are found in orbitals around the nucleus
The farther away from the nucleus, the more energy an electron has
Compounds
A compound is a substance made of two or more different elements that are chemically bonded
Compounds are unique A chemical formula shows the kinds and
proportions of atoms of each element in the compound
For example: Fe2O3
2 iron atoms and 3 oxygen atoms
How many of each?
C8H10N4O2
C3H8O
KMnO4
CaCl2
H2O
NaCl
Molecules
A molecule: is the simplest part of a substance that retains all of the properties of the substance and can exist in a free site
Some molecules are composed of atoms of different elements
Some molecules are composed of atoms of the same element
Diatomic Molecules
Are molecules composed of atoms of the same element
Examples: Hydrogen, Iodine, Bromine, Oxygen, Nitrogen, Chlorine, & Fluorine
HI BrONClF
Pure Substances & Mixtures
Pure Substance: is matter that has a fixed composition and definite properties
Examples: Elements & Compounds Mixture: is a combination of 2 or more
substances that are NOT chemically combined
Examples: Air & Grape Juice
Mixtures
Can be separated They are formed by mixing pure
substances They have properties similar to the
pure substances that make them up Mixtures are classified by how well
they are mixed
Types of Mixtures
Heterogeneous: substances in which components are NOT distributed evenlyExamples: flour & water, sand & salt
Homogeneous: substances in which the components are evenly distributedExamples: Pop, sugar & water
Miscible: A homogeneous mixture of liquidsExample: Gasoline
Immiscible: A heterogeneous mixture of liquidsExample: Oil & Water