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 substance can 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 meltingevaporation 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 O2O2 Fe NaCl

Compounds Compound Formula Elements Water H 2 O hydrogen, oxygen Carbon Dioxide CO 2 carbon, oxygen Vinegar CH 3 COOH 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!

Electrons Elements 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?

makes a happy atom! Remember

2-8 makes a happy atom! 2-6Wants 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 H 2 O 2 N 2