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Provide the following information on the slip provided Name …the one you want to be called. Code name…a clean one…I will use this to post your grades. Indicate if you require a front desk …include if the reason is for vision.
Info sheet 2
The science that deals with the structure and behavior of matter
Unit I Classification of Matter Chemistry – - the study of matter and its changes. Matter – – anything that has substance and takes up space. Data is gathered by investigation and observation. Observations are statements of fact 2 kinds of observations Quantitative – involves measurement (numbers) Qualitative – all the rest
Physical & Chemical Properties Physical & Chemical Changes How to determine if an observation is Physical or Chemical Ask the question; Is new matter being formed? If the answer is YES……… CHEMICAL If the answer is NO……… PHYSICAL How to determine is the observation is a change or a property. If the verb ends in ing ….. CHANGE If the verb does not end in ing……. PROPERTY Note: All phase changes are physical changes
Physical properties – color, hardness, texture, phases, density, ability to conduct heat, electricity. When a physical change occurs a physical property will be different. For example, melting ice. Heat
Ca O Ca SS8S8 O2O2 Chemical change – a substance changes from one type of matter to another.
Describe each of the following as a Physical Property, Physical Change, Chemical Property or Chemical Change 1.Moth balls melt at 56.0 o C. 2.Material A exists as a yellow powder. 3.A plant growing. 4.Crushing rock. 5.Propane burns in air. 6.Water condenses at 100 o C. 7.HCl (aq) is neutralized when it reacts with NaOH (aq). 8.Breaking a piece of Chalk.
Describe each of the following as a Physical Property, Physical Change, Chemical Property or Chemical Change 1.Moth balls melt at 56.0 o C. PP 2.Material A exists as a yellow powder. PP 3.A plant growing. CC 4.Crushing rock. PC 5.Propane burns in air. CP 6.Water condenses at 100 o C. PP 7.HCl (aq) is neutralized when it reacts with NaOH (aq). CP 8.Breaking a piece of Chalk. PC
A cube of table sugar is dissolved in de-mineralized water. Classify (describe) this sample of matter using as many terms as you can. Solution Mixture Liquid (solid, gas) Homogeneous (heterogeneous) 2 compounds (water and sugar) (element) Non – electrolyte (electrolyte) Neutral (acid, base) Molecules (ions) C 12 H 22 O 11 (aq)
Definitions Homogeneous - sample is uniform throughout (same physical and chemical properties) Heterogeneous - non uniform mixture; you can see individual parts of the mixture. That is – parts have different chemical and physical properties. Pure substances - samples of matter that have a definite set of physical and chemical properties. (elements or compounds)
Mixtures - a combination of substances that have no definite or fixed proportions. Solutions - homogeneous mixtures Elements - a pure substance that cannot be broken down into different kinds of matter. (contains only one kind of atom) Compounds - elements chemically combined in definite proportions. Elements
Compounds vs Mixtures Compounds Mixtures Components lose their identities. (C & P properties) Components retain their identities. (C & P properties) Components are present in fixed proportions. Components may be present in any proportion. Components can be separated by chemical means only. Components can be separated by simple physical process. Evidence of chemical action during preparation. (heat, light, color change etc) No evidence of chemical action during preparation
A Classification Scheme Matter Homogeneous Pure substances Elements Metals Non metals compounds mixtures solutions Heterogeneous mixture
Bar of zinc C 3 H 8(g) glass of 7-up Shovel of dirt from the field Helium gas NaHCO 3 dissolved in water Gold coin Complete the following table by placing an x for all that apply element solution compound mixture HomogeneousHeterogeneous metal ? Sample of Matter
Bar of zinc xxx C 3 H 8(g) xx glass of 7-up xxx Shovel of dirt from the field xx Helium gas xx NaHCO 3 dissolved in water xxx Gold coin xxx Complete the following table by placing an x for all that apply element solution compound mixture HomogeneousHeterogeneous Metal ? Sample of Matter
Kinetic Molecular Theory (KMT) 1.We believe that all molecules are in a state of constant motion. 2.Three kinds of motion are possible: A) Vibrational – back and forth B) Rotational – spinning on an axis C) Translational – movement through space 3. We use this theory to explain the states (phases) of matter.
Solids Liquids Gases Molecules vibrateMolecules vibrate and rotate Molecules vibrate, rotate and translate Definite shape Shape of the container Definite volume Expand to occupy all the available space High attractive forces between molecules Weak attractive forces between molecules Very weak attractive forces between molecules Molecules very close together Molecules very far apart Orderly arrangement of molecules Molecules very dis-organized More orderly than gases but less than solids Not very compressible Very compressible
Heating of a solid Temp. ( o C) Time(s) A BC DE F A B : Heating of a solid B C : Melting of a liquid (Phase change) C D : Heating of a liquid D E : Evaporating a liquid (Phase change) E F : Heating of a gas (closed system)