MATTER & ITS INTERACTIONS BIG IDEA 1

WHAT IS PHYSICAL SCIENCE? The study of what things are made of and how they change

Composition of Matter ATOMS The basic unit of all matter Super small Made up of a dense nucleus and moving electrons

Simplified Structure of the Atom

Elements vs. Compounds ElementCompound Made of 1 type of atom Has certain properties Made of 2 or more types of atoms Different properties than the elements it’s made of

Question… So how do atoms combine to form different substances? Don’t write

BONDS Atoms combine to form new substances by forming bonds Different types of bonds form different types of compounds

Covalent Bonds Atoms SHARE one or more electrons with each other to form MOLECULES

Ex: Water 1 oxygen atom shares electrons with two hydrogen atoms.

What do we know about water? What do we know about oxygen? What do we know about hydrogen?

The compound “water” has different properties than its parts!!!

Other examples Glucose (used for energy in living things)

Example Caffeine (used for keeping Mr. Lazreg awake)

Let’s see if you can figure it out! Carbon – can form 4 covalent bonds Oxygen –2 covalent bonds Nitrogen – 3 covalent bonds Hydrogen – 1 covalent bond Chlorine – 1 covalent bond

Chloroethane = C 2 H 5 Cl Propanol = C 3 OH 8 (2 right answers) Ammonia = NH 3 Cyclobutane = C 4 H 8 Benzene = C 6 H 6 (each C attached to 1 H) Show me at each one for a picture… First group wins!

Polymers Sometimes small molecules combine like links in a long chain of repeating units (monomers) called polymers

Examples: Glucose is joined into long chains (starches) Nylon

Polymers can have useful properties like higher boiling points, strength and ability to be used as lubricants

Crystals Molecules bond together in regular, rigid patterns that form crystals with special properties Some can bend light Some can change electrical energy into mechanical energy

Molecular Structure The shape, composition, and size of molecules determine the properties of a substance.

Ionic Bonding One atom “donates” electrons to another An ion is an atom that has gained or lost an electron

Ionic Bonding Donator becomes positively charged (+) cation Receiver becomes negatively charged (-) anion +-

Ionic Bonding Opposites attract! Crystal Lattice Not Molecules

Ionic Bonding Ionic Compounds Have… High melting points High boiling points Conduct electricity when liquid or dissolved in water

Matter and Motion Atoms, molecules and crystals are ALWAYS in motion

Pure vs. Mixture Pure Substance Mixture Cannot be separated without a chemical reaction forming different substances Ex: Carbon Dioxide, Water, Gold Combination of substances that can be separated by physical means into what its made of Ex: A fruit salad, iced tea, salt water

Properties of Matter Physical Properties Learned from observation/measureme ntLearned from observation/measureme nt Color, Size, Shape, FeelColor, Size, Shape, Feel PhasePhase Boiling/Melting PointBoiling/Melting Point What about density?What about density? Chemical Properties Only found by actually having it undergo a chemical changeOnly found by actually having it undergo a chemical change How it chemically reacts with other substancesHow it chemically reacts with other substances Ex: potassium metal reacts violently with waterEx: potassium metal reacts violently with water

Physical or Chemical Property? The ball is blue Na reacts with Cl to make NaCl Sugar dissolves in water Dynamite explodes when burned Olive oil floats on water Potassium makes hydrogen gas when put into water Water freezes at 0 Celsius Physical Chemical Physical Chemical Physical

Matter and Change Physical Change The identity of the substance stays the sameThe identity of the substance stays the same Ex: Reshaping puttyEx: Reshaping putty Chemical Change The substance is changed into something elseThe substance is changed into something else Ex: Gasoline reacts with air to form CO 2 and H 2 OEx: Gasoline reacts with air to form CO 2 and H 2 O

Evidence of Chemical Change Color change Evolution of a gas Odor Change in temperature / release of light

Evidence of Chemical Change Formation of a precipitate (a solid that forms when liquid solutions are mixed)

Physical or Chemical? Crumpling a piece of paper Burning a piece of paper Dissolving salt in water Baking a cake Cutting an apple in half Frying an egg Digesting an egg Physical Chemical Physical Chemical

Phases of Matter Solid Fixed shape Fixed Volume Molecules locked in place (but vibrating) Liquid Fixed volume No fixed shape Molecules can flow Gas No fixed shape Takes the volume of its container Molecules move freely

Phases of Matter Plasma At super high temps atoms can lose some electrons The extremely hot “soup” of atoms and electrons is called Plasma

Phases of Matter

Matter and Energy Kinetic Energy The energy of motion More energy = faster motion Vibration counts

Matter and Energy Where is the kinetic energy in this picture?

Matter and Energy Even in a single substance, not all particles are moving at the same speed (with the same energy)

Matter and Energy Temperature A measurement of the average kinetic energy of all the particles in an object

Matter and Energy Thermal Expansion When a substance is heated, it expands. When cooled, it contracts.