Chemistry
NCSCOS Overview
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Chemicals
• A chemical is a substance used in or formed by
a chemical process
• Chemicals are
– NATURAL – occur naturally
– SYNTHETIC – man-made and don’t exist in nature
Matter
• Matter is anything that has mass and takes up
space
• Most basic type is elements
• Elements are naturally occurring or synthetic
– Naturally occurring – oxygen, hydrogen, copper,
gold
– Synthetic – neptunium, plutonium, americium,
curium (end in –ium and are at end of periodic table)
Matter
Matter
• Elements are made of atoms – the smallest
particles of pure substances
• Atoms are made of protons, neutrons, and
electrons
• Protons = atomic #
• Neutrons = a.m. – atomic #
• Electrons = atomic #
Matter
• PRACTICE WITH YOUR GROUP:
• How many protons, neutrons, and electrons are
in an atom of the following elements:
Carbon
Lithium
Sodium
Chlorine
Matter
• Atoms combine to form molecules and
compounds
• A molecule is two or more of an atom
chemically joined together
• A compound is two or more TYPES of atoms
chemically joined together
Matter
Oxygen gas is a molecule but
not a compound
H2O is a molecule and a
compound
How is this a molecule?
How is this a compound and
a molecule?
Matter
• All living and nonliving substances are made of
up atoms!
• Some living and nonliving substances are not
made of just one element and are compounds!
Periodic Table
• Information about elements is organized on to a
large data table called the PERIODIC TABLE OF
ELEMENTS
Periodic Table
• The periodic table is arranged by atomic number
• The periodic table is arranged in periods (rows)
and groups or families (columns)
A
B
• Groups on the periodic table have similar
properties
Periodic Table
• The periodic table is arranged by properties of
elements too! http://www.sing-smart.com/LyricsDetails.asp?SongCategoryID=6
Metals and Non Metals
• The periodic table is made of metals, non metals,
and metalloids – this should help you understand:
Metals
Nonmetals
Malleable – can be hammered
Brittle – break easily
Ductile – can be drawn into a
wire
Dull – not shiny
Conductors – can conduct
electricity (also magnetic)
Luster
Poor conductors
Key Vocabulary
• Words you need to know:
– Malleable
– Ductile
– Conductor
– Magnetism
– Solubility
– Density
– Boiling point
– Melting point
Key Vocabulary
• Words you need to know:
– Malleable – can be hammered/shaped
– Ductile – can be stretched into a wire without breaking
– Conductor – can conduct heat or electricity
Key Vocabulary
• Melting point – the
temperature when a solid
turns to a liquid
• Boiling point – the
temperature when gas
bubbles are formed in a
liquid
Key Vocabulary
• Words you need to know:
– Magnetism – a force between like or unlike poles
– Solubility – ability to dissolve
– Density – mass per unit volume (mass divided by volume)
Chemical Formulas
• We use chemical symbols and chemical
formulas to represent what is present in pure
substances and in compounds.
• For example:
–H2O
CO2
C6H12O6
NaCl
Chemical Formulas
The letters are chemical symbols
The small numbers are subscripts
The large numbers are coefficients
Knowing this, we can calculate how many atoms
of each element are in a chemical formula
• For example:
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–3H2O
9CO2
C6H12O6
4NaCl
Chemical Formulas
• PRACTICE
• How many of each atom in each of the
following formulas?
–2H2O
–3C6H12O6
–8CO2
–NaCl
Chemical Equations
• A chemical equation shows what happens
during a chemical reaction
• There is a reactant, an arrow, and a product in
every chemical equation (RAP)
• It is important for you to know if chemical
equations are balanced or not
How do you know…
2H O
2
2H + O
2
2
Chemical Equations
• Photosynthesis
– What are the products?
– What are the reactants?
– Is it balanced or not?
• Cellular Respiration
– What are the products?
– What are the reactants?
– Is it balanced or not?
Law of Conservation of Matter
• Matter, or mass, cannot be created nor destroyed!
• Simply put, nothing can simply appear or
disappear!
• You must have the same stuff at the beginning as
you do at the end
• How can you tell if an equation supports this law?
Changes in Matter
• Physical Changes?
• Chemical Changes?
• How do you know when each has occurred?
Changes in Matter
• Physical
– Change in size, shape, or state!
• Chemical
– Change in color
– Change in odor
– Change in temperature
– Creation of a gas or a solid
Physical or Chemical
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Tearing paper?
Grape?
Mixing?
Ice?
Photosynthesis?
Respiration?
Smores?