Matter chapter 3

Matter Anything that has mass and occupies space Mass is measured in grams or kilograms Space or volume is measured in liters or cm3

Phases SOLIDS LIQUIDS GASES

Solid: definite volume definite shape

Liquid definite volume indefinite shape takes the shape of container

Gas indefinite volume indefinite shape takes the shape and volume of container

States of Matter How are the particles packed in each phase? source How are the particles packed in each phase? How do the particles move in each phase? Why do liquids and gases flow? Why are gases so easy to compress?

4th Phase of matter Plasma exists in stars electrons are stripped from atoms

Physical Properties Describe the appearance and form of matter Words: color, texture, luster, odor, solid, liquid, gas Measurements: a number and a unit

Intensive properties Physical Constants independent of sample size Density, freezing point, and melting point Solubility in water (g/ml)

Extensive Properties Mass  volume depends on amount of matter in sample Extensive properties depend on quantity of matter

Chemical Properties Describe how matter behaves in presence of other matter Describe how matter changes into another kind of matter Flammability Resistance to corrosion Ability to neutralize acids or bases

Properties of Copper Physical Prop. Reddish brown Shiny Malleable Ductile Good Conductor Density = 8.92 g/cm3 MP = 1085C BP = 2570C Chemical Prop. Reacts to form green copper carbonate Forms a deep blue solution when in contact with NH3 Forms new substances with HNO3

Physical Change The form or appearance of sample may change but identity remains same Cutting, crushing, grinding,tearing Phase changes Dissolving

Dissolving Dissolving is physical change Think of sugar in water still have sugar – you just spread it out with water molecules in between C6H12O6(s)  C6H12O6(aq)

Phase Changes Phase changes are physical changes No new substance is created (chemical formula stays the same) Ex: ice melting: H2O(s)  H2O(l) water boiling: H2O (l)  H2O(g)

Chemical Change chemical change - identity of matter is changed new substance with unique properties is formed The chemical formula changes Ex: 2H2O(l)  2H2(g) + O2(g)

Burning Common name for oxidation reaction Burning means reacting with oxygen Burning is chemical change, because original substance is changed into new kinds of matter Ex: CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)

What kinds of matter are there?

Matter Substances Mixtures Mixtures  Separated by physical methods Elements Compounds Heterogeneous Homogeneous Mixtures  Separated by physical methods Compounds  Separated by chemical methods

Element Substance that: Formulas have 1 uppercase letter cannot be broken down or decomposed into simpler substance only 1 kind of atom has definite properties Formulas have 1 uppercase letter

Element Song Big Bang Version sung by Sheldon

Atom smallest particle of element that retains properties of element smallest particles of element that can undergo a chemical reaction Atoms can be combined to form molecules

Compounds 2 or more elements chemically combined in a definite ratio Properties are different from those of elements formed from Homogeneous Broken into elements by chemical decomposition reaction Formulas have 2 or more uppercase letters

Elements can be chemically combined to form compounds, atoms are combined to form molecules Molecule: A substance that is made up of 2 or more atoms of elements Examples: H2, O2, N2 Note: theses are not compounds because each is composed of a single element H2O, CO2 are molecule, but they are also compounds

2Na + Cl2  2NaCl Na = atom, element Cl2 = molecule, element NaCl = molecule, compound Atoms or Molecules? Element or Compound?

        Particle Diagrams Atoms of a monatomic element         Molecules of a diatomic element        

         Particle Diagrams Molecules of a triatomic compound         Mixture: monatomic element, diatomic element, triatomic compound             

Mixtures Combo of 2 or more pure substances Physically combined not chemically combined Each substance retains its own identity and properties

Mixtures Variable composition No unique properties (Think of sugar and salt mixed together) Separated by physical methods May be homogeneous or heterogeneous

Types of Mixtures Heterogeneous: definite variation in composition, individual components visible (2 types – colloids and suspensions) Oil in water Salad dressing Granite

Colloids (type of heterogeneous mix.) Particles are suspended- they are too small to see but they are larger than molecules (like Sugar, Salt, etc)

Example of Colloids: Aerosols: solid or liquid particles in gas Ex: Smoke: solid in a gas Gas in liquid: Ex: whipped cream Emulsion: liquid in liquid Ex: mayonnaise (oil suspended in water – use egg yolk to Sols: solid particles in a liquid Ex: Milk of Magnesia (solid magnesium hydroxide in water) Gels: Liquid in solid Ex: Quicksand: sand in water

Suspensions particles in suspensions are larger than those in solutions components of suspension can be evenly distributed by mechanical means (shaking the contents) but components will settle out Settle out on standing Can scatter light

Homogeneous (aka solutions): constant composition throughout, individual components not visible Ex: salt water

Solution vs Suspension Solutions in gas & liquid phases transmit light particles not big enough to scatter light look translucent Suspensions look cloudy particles big enough to scatter light settle on standing

CuSO4(aq) source source

Separating Mixtures Physically combined Separation based on physical properties 1. Sorting: size & appearance

2. Filtration: size solid in liquid Can you filter a solution? Like sugar water? NOTE: Sand and water is SiO2 + H2O or SiO2(aq)

3. Distillation: different bp’s liquids mixed

4. Crystallization: solubility solid in liquid

5. Magnet: magnetization

6. Chromatography: solubility liquids mixed - “Travel” ability

Conservation of Mass Mass before = Mass after # of atoms before = # of atoms after