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Introduction to Chemistry. Chapter 7. Chemistry. The study of matter , its structure and the changes it undergoes. MATTER. Anything that has mass ( stuff inside ) & takes up space ( volume ). It is all around us: trees, houses, soil, water, clouds, sun, us.
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Introduction to Chemistry Chapter 7
Chemistry • The study of matter, its structure and the changes it undergoes.
MATTER • Anything that has mass (stuffinside) & takes up space (volume). • It is all around us: trees, houses, soil, water, clouds, sun, us. • All things are made of matter.
Atom • Small particle of matter. • Basic building block of matter.
Protons- (+) Positive Charge, found in nucleus • Neutrons- NO charge, found in nucleus • Electrons- (-) Negative Charge, found outside the nucleus.
Substance • Matter that always has the composition (makeup). • Aluminum, oxygen, & water. • Has same type of atoms. • 2 types: elements, compounds
ELEMENTS Pure substance that contains only type 1 atom Aluminum foil consists of trillions of aluminum atoms.
Elements • Represented by Chemical Symbols • Ex. O = Oxygen
A pure substance • ONE Capital Letter • Examples: H, Na,Cl
Chemical Symbol = ElementExamples: N, O, C,Ne, Co, Cl, H+, Ca-Elements/Atoms cannot be broken down any more.
H = He = Li = Hydrogen Helium Lithium Elements Responsible for…
Made up of 2 or more elements • First letter CAPITALIZED, second letter lowercase, Na, Fe, NaCL (salt), CaCl, • 2 CAPITAL LETTERS
Chemical Formula • A combo of symbols & numbers that represent a compound. • Tells elements, & number of atomsthat combine to make compound.
Chemical Formula Examples Na • NaCl (SALT) - one atom of Na (sodium) + one atom of Cl (chlorine) • H2O (water)- 2atoms of H & one atom of O. • CO2 (Carbon Dioxide)- one atom of C & 2atoms of O. Cl O H H O O C
Chemical Formula = CompoundCompounds can be broken down into elements.
Chemical Bond • Is formed when 2 or more atoms combine. • H2O =2 Hydrogen atoms combine with 1 Oxygen atom. • CO2, C12H22O11, CO
Properties of Compounds • Atoms when combined to make a compound act differently than when they are by themselves. • CO2 (Carbon Dioxide)- gas , but C is a black solid, & O is a gas that helps fuel burn. • NaCl (Salt)- Na is explosive in water, Cl is a poisonous, yellow-green gas. When they combine they make • something we put on our food.
Molecules • Formed when atoms combine. • 2 Hydrogen + 1 Oxygen = Water Molecule (H2O) • 1 Carbon atom + 2 Oxygen atoms = Carbon Dioxide Molecule (CO2)
Circle the ELEMENTS • Box the COMPOUNDS • X the IONS
Mixtures • Another form of matter. • Varies in composition. • Physically blended together, not CHEMICALLY COMBINED!
Mixtures • Made of 2 or more substances that are not combined chemically.
Mixtures can be broken down physically. • A filter, by hand, a magnet, dissolving, evaporation.
Heterogeneous Mixture • A mixture that is NOT well mixed. • Can see the different parts of the mixture. • Hoagie, Salad, Taco, Cheeseburger
Homogeneous Mixture • A well-mixed mixture. • Can’t see each part. Evenly mixed. • Suntan lotion, ocean water, lemonade
Solution • A homogeneous mixture where one substance (solute)gets dissolved in another liquid (solvent). • Well-mixed, salt water • Coke, Lemonade, Brass.
Atoms, Mixtures or Compounds? Identification
Atoms, Compound, or Mixture? • A B C X XY X XY Y Y XY X X X X XY XY Y X XY X X X Y X
Compound (A) XY XY XY XY XY
Atoms (Elements) (B) X X X X X X X X X
Mixture (C) Y Y X X X Y X Y
2 Properties of Matter • 1. Physical • 2. Chemical
Physical Properties • Can be observed without changing it into a new substance
Examples • Solid, Liquid, Gas, Texture, Color, Freezing, Melting, & Boiling Points
Measuring Matter • Mass • Weight • Volume • Density • Conductivity • Solubility
Mass • The amount of matter (“stuff”) inside in an object. • Holding a basketball vs a bowling ball. • Bowling ball heavier because it has more mass (stuff) inside it.
Weight • Is the measure of the force of gravity on an object. • IT varies by location. • A basketball weighs more on Earth than on the moon. • Earth bigger more pull (Gravity) than moon so bball weighs more • on Earth.
On Earth I weigh12O lbs, on Jupiter I would weigh304lbs, on the moon I would weigh19 lbs. WHY?
Mass • A measure of the amount of matter in an object • CONSTANT
Volume • The amount of space an object takes up. • Ml, L, cm3, • 2 liter bottle of coke, can of coke is 12oz • 355ml.
Volume Length x Width x Height Units = Cubic
Density • Mass per unit volume. (thicker) • Plastic bat vs wooden bat, wooden bat thicker more dense. • Density= Mass/volume
Sink or Float? Density
Object > 1.0 = SINK Object < 1.0 = FLOAT