Matter & Change 1

What is matter? Matter is anything that has mass and takes up space. Quantifying Matter – Measuring Matter Mass – measure of the amount of matter. Volume - amount of three-dimensional space an object occupies. 2

3 States of Matter The physical forms in which a substance can exist Bose-Einstein Condensate Solid Liquid Gas Plasma

The Different States of Matter StateExampleCharacteristics Solid Definite volume & definite shape Liquid Definite volume; takes shape of container Gas No definite shape or volume Plasma Exists at high temps; No definite shape or volume 4

States of Matter on a Molecular Level StateWhat is happening at the molecular level? Solid Liquid Gas Molecules are close together, have strong attractions for each other, are locked into position, and only have vibration motion Molecules are moving slowly, are close to each other, have attractions to each other that are constantly forming and breaking Molecules are in constant rapid motion, are widely separated, are not attracted to each other, and they bounce off each other when they collide 5

Phase Changes Solid Liquid Gas Melting Evaporation Condensation Freezing Sublimation Deposition 6

7 Phase Changes SOLIDSOLID Gas Sublimation Deposition

Physical Property vs Chemical Property Physical Property - property that can be observed or measured without changing the identity of the substance Chemical Property - property that cannot be observed without permanently altering the substance's identity 8

Physical Properties Examples of Physical Properties: 1. Mass 2. Volume 3. Density 4. Temperature 5. Length 6. Melting Point 7. Boiling Point 8. Solubility 9. Concentration 10. Pressure 11. Specific Heat 9

10 Chemical Properties Examples of Chemical Properties: 1. Flammability 2. Toxicity 3. Reactivity 4. pH

11 Physical Change vs Chemical Change Physical Change - a change in a substance that does not involve a change in the identity of the substance. The substance may look different but it still remains the same. Chemical Change - a change that occurs when one or more substances change into entirely new substances with different properties

Physical Changes Examples of Physical Changes: 1. Change of state or phase (such as from solid to liquid) 2. Dissolving a substance 3. Absorption of water into a towel 4. Crumpling a piece of paper 5. Pulling copper into a thin wire - a change of shape, but not a change of composition 6. Cutting a material such as wood 7. Ripping a piece of aluminum foil 12

Chemical Changes Examples of chemical changes: 1. Burning anything. (Not Melting or Boiling) 2. Mixing an acid with a base, producing water and a salt. 3. Photosynthesis - a process in which carbon dioxide and water are changed into sugars by plants. 4. Decomposition of organic matter (for example, rotting food, food going bad). 13

Evidence of a Chemical Change 1. Can not get back to the original substance 2. Change of color (for example, iron to reddish-brown when iron rusts). Note: Color change is typically a good indication of a chemical change but one should look for other evidence as well. 3. Release of odor 4. Release/absorption of heat (increase or decrease of temp) 5. Change of form (ie.: burning paper) 6. Release /absorption of energy (light or sound) 7. Formation of gases (bubbles or smoke). 8. Formation of a precipitate (solid particles). 14

Examples of Chemical Changes 15

Pure Substances Pure Substance - a substance that always has the same composition Examples: elements, molecules, and compounds Properties of Pure Substances Every sample of a pure substance has exactly the same characteristic properties. Every sample of a pure substance has exactly the same composition. 16

Building Blocks of Matter Element - any substance that cannot be broken down into simpler substances Found on the periodic table. 17

Building Blocks of Matter Compound - a substance made from two or more different elements that are chemically combined. 18

Building Blocks of Matter Molecule – a collection of elements bonded together that behave as a unit. They do not need to contain two different elements. 19

20 Building Blocks of Matter Diatomic Molecules – Molecules that are composed of two atoms. Eight elements exist in the diatomic state: H 2, N 2, O 2, F 2, Cl 2, Br 2, I 2, and At 2

Mixtures Mixture - A substance composed of two or more elements or compounds that are physically mixed together but not chemically combined. Mixtures are physically combined and can be separated Mixtures are not only liquid. There can be solid, liquid, and gas mixtures 21

Types of Mixtures Homogeneous mixture – a mixture in which the composition is uniform throughout Examples: Salt water, air, alloys, carbonated water Heterogeneous mixture – a mixture that is not uniform throughout. Examples: Sand and water, salad dressing, oil and water 22

23 Alloys Metallic Alloys – a homogeneous mixture of two or more metals Carbon Steel - Iron with Carbon Stainless Steel - Iron with Chromium Brass - Copper with Zinc Bronze - Copper with Tin Pewter - Tin with Copper

24 Alloys Aluminum - Aluminum with various elements Silver - Silver with Copper Gold - Gold with Silver and/or Copper 24 karat = 24 parts of gold (very soft) 22 karat = 22 parts gold : 2 parts Silver/Copper 18 karat = 18 parts gold : 6 parts Silver/Copper 14 karat = 14 parts gold : 10 parts Silver/Copper 10 karat = 10 parts gold : 14 parts Silver/Copper

25

Homogeneous or Heterogeneous? Homogeneous Homogeneous HeterogeneousHeterogeneous Heterogeneous Homogeneous 26 Brass Mellophone Smoke & Air Trail Mix Milk Aluminum Can Coke Inside Granite Rock

Classification of Matter Matter Can it be separated? MixturesPure SubstancesIs the composition uniform? HomogeneousHeterogeneous Yes No Can it be broken down ordinarily? CompoundElement Yes No Yes No 27

28 Separation Techniques Mixtures can be separated into their individual components. Following are various separation methods...

Separation Techniques  Gravitational Filtration - uses gravity and filter paper to separate heterogeneous mixtures of liquids and solids. 29

Separation Techniques  Magnetism- used to separate magnetic matter from non-magnetic matter.  Usually used to separate solid magnetic material from solid non-magnetic material. 30

Separation Techniques  Electrolysis - use of electricity to separate compounds. 31

Separation Techniques  Vacuum Filtration - uses vacuum suction to separate heterogeneous mixtures of solids & liquids. 32

Separation Techniques  Separatory Funnel - used to separate heterogeneous mixtures of 2 or more liquids. 33

Separation Techniques  Distillation- uses different boiling points to separate homogeneous solutions formed from 2 or more liquids. 34

Separation Techniques  Centrifuge- uses rapid spinning to separate solids from liquids. 35

Separation Techniques  Chromatography- used to separate homogeneous mixtures through the use of a solvent & a medium. 36

Separation Techniques  Recrystallization- a separation technique in which the temperature of a solvent is increased to allow the solute to dissolve and then allowed to cool, which promotes the formation of solute crystals 37

Separation Techniques  Crystallization- separates a solid that is dissolved in a liquid through evaporation. The liquid evaporates & the solid recrystallizes. 38