Matter
Vocabulary!Matter: anything that has mass and takes
up space.
Mass: measure of the amount of matter in an object. Constant. Measured in Kg
Volume: amount of space an object takes up.
Weight: measure of the gravitational force on an object. Changes. Measured in newtons.
Density: ratio of the mass of a substance to the volume of the
substance. D=M V
Mass vs Weight
• Transparency in chem folder
So then, what’s density?
• It’s the amount of mass in a given volume
Important stuff Density = Mass Volume
Water has a density of 1.0
So if the density is lower that that, it floats
If the density is greater than 1.0, it sinks!
States of Matter
Physical states in which a substancecan exist.
Fill in the chart with + or -
Shape Volume Solid Liquid
Gas
• Solid-constant shape and volume
• Liquid-no shape, has a constant volume
takes on shape of container
• Gas-no shape or volume.
takes on shape of container, but FILLS it
Solid
Particles are close to each other and vibrating
Liquid
Particles move faster, and away from each other
Why is this bug not sinking?
Surface tension: force that acts on the particles on the surface of a liquid.
Gas
• Particles travel away from each other VERY FAST
• They push on the container wall, causing PRESSURE
• Volume increases with heat, decreases with cold
States of Matter
Change of state: change of a substance from one physical state to
another. This change uses or loses energy
Melting: change of state from solid to liquid. Energy added.
Freezing: change of state from liquid to solid. Energy removed.
Evaporation: change of a substance from liquid to gas at the surface. Boiling: change of a liquid to a gas throughout the substance.
Condensation: change of a gas to a liquid.
Changing States
melting evaporation
What’s it called when water goes from a gas to a liquid?
• Solid->Liquid->Gas
• Uses Energy
• Gas->Liquid->Solid
• Gives off Energy
States of Matter
Chemical vs Physical Properties
Physical properties: characteristics that can be observed without changing the substance. Do not change with the amount
Example: color and density
Chemical properties: characteristics that describe a substance’s ability to change.
Baking soda can react with vinegar
Chemical vs. Physical Changes
Physical change: substance is not altered chemically, but changed to another state. or separated or combined.
Chemical change: substance is altered chemically and displays different physical and chemical properties.
Chemical or Physical Property?
1. Water boils at 100 degrees C
2. Diamonds are able to cut glass
3. Iron rusts in a damp environment
4. Salt is dissolved in water
5. Dry ice sublimes at room temperature
Chemical or Physical Property?
Gasoline burns in the presence of oxygen
Bromine has a red color
Hydrogen Peroxide decomposes to water and oxygen
Vinegar will react with baking soda
Aluminum has a low density
Chemical or Physical Property?
Wood is flammable
Ammonia is a gas at room temperature
Yeast uses sugar to form carbon dioxide and ethanol
Water can be separated by electrolysis into hydrogen and oxygen
Review• A Physical property is one you can see or
measure• A Chemical property is how an element
behaves in a reaction
• A Physical change is a change of state—the element is the same element in the end
• In a Chemical change, the substance changes into a different substance
Vocabulary
element-a substance that cannot be broken down
compound-combination of different elements
atom-smallest indivisible particle of matter
molecule-2 or more atoms bonded together O2
Fe
NaCl
Compounds
Compound Formula Elements
• Water H2O hydrogen, oxygen
• Carbon Dioxide CO2 carbon, oxygen
• Vinegar CH3COOH carbon, hydrogen,
oxygen
Atoms
Nucleus—contains most of the mass protons and neutrons
Electrons-orbit in a fast moving cloud
Atomic Nuclei
Protons—positive charge
Number of protons = Atomic Number
Neutrons—no electrical charge
Neutrons + protons = Mass Number
Electrons—negative charge
Add to Vocabulary List
Proton—positive charge. In nucleus.Neutron—no charge. In nucleus.Electron—negative charge. In cloud.
Add to Vocabulary List
• Atomic Number---number of protons
• Atomic Mass—(mass number)
number of protons + neutrons
A Variation—add to List
Isotope-atoms of the same element with different number of neutrons many are radioactive
Carbon 14—used to date fossils
Atoms with the same number of protons (+)
and electrons(-) are neutral
Remove an electron, and it becomes POSITIVE: a positively charged ion
Add an electron, and it becomes NEGATIVE: a negatively charged ion
Your turn!
• Turn to page 521 in your science textbook.
• Math Focus
• Continue with Atomic Charges
Electron Energy Levels
• Remember the 2-8 Rule!
Carbon
Atomic Number 6
Shells are 2--4
The number of electrons in the outer shell determines the behavior!
ElectronsElements with one electron in the outer
shell are very reactive
Sodium
Elements with 7 electrons are also! Chloride
Elements with 8 electrons in their outer shell are very stable
noble gases (inert)
Oxygen has an atomic number of 8. What is its configuration?
2-8-1 2-8-2
2-8 makes a happy atom!Remember
2-8 makes a happy atom!
2-6 Wants 2 2-7 Wants 1
Remember
Look at the Periodic Table
Ionic Bond
Sodium (Na) donates one electron to Fluoride (Fl)
NaFl
Covalent Bond
• Atoms SHARE electrons
• Stronger than ionic bonds
Chloride— 7 in outer shell
Hydrogen—1 in outer shell
2 electrons are shared so the shells are 8 and 2—stable!
HCl
Ionic and Covalent Bonds
• Ionic—electrons are donated
Metal with non-metal
Valence number—tendency to gain or lose
electrons
example: Na +1
• Covalent—electrons are shared
Two types
Polar and Nonpolar
Polar Covalent Bonds
• Electron sharing is NOT equal
• One end pulls HARDER
• Makes one end more negative and the
other more positive
Example: Water!
H and O atoms
Nonpolar Covalent Bonds
• Electrons are shared equally
• Entire molecule has same charge
examples: diatomic gases
H2 O2 N2