Physical And Chemical Changes Change Is CCOOOOLL
7/6/2009Physical and ChemicalChangesChange is COOL!Physical vs. Chemical ChangesPhysical changes occur when substances orobjects undergo a change without changing intoanother substanceChemical changes are changes substances undergowhen they become new or different substances.1
7/6/2009Physical vs. Chemical ChangesRemember that after a: Physical change – object’s identity remains the same Usually involves energy (like heat) and states ofmatter. Chemical change – object’s identity changes Chemical changes happen on a molecular levelhttp://www.chem4kids.com/files/matter chemphys.htmlPhysical ChangeMelting of ice cream is anexample of a physical change.- Involves heatImage available athttp://www.icecreamclubonline.com/YOUR TURN: Can you think of other examples ofphysical changes?2
7/6/2009Chemical ChangeBurning of a candle is anexample of a chemicalchange.At the molecular level: Thewax molecule changes tocarbon dioxide and watermolecules.Image available at Colin Baird, “Chemistry in Your Life”. 2nd ed.,(ISBN 00-71677167--70427042-3) New York: W.H. Freeman, 2006.Other examples of chemical changesTarnishing of silverImage available hoto.asp?imageid 1263140Corrosion (rusting) of ironImage available athttp://www.mrmartinweb.com/bicycle.html3
7/6/2009Other examples of chemical changesCan you think of another term for chemicalchanges?Chemical change chemical reactionYOUR TURN: Can you think of other examples ofeveryday life chemical reactions?Can you identify the following changes asphysical or chemical?Melting of iceDigestion of foodFormation of frost on your windowMilk turns sourCrushing a plastic bottleFireworks4
7/6/2009Collecting and Preserving EvidencePhysical and chemical changes are sometimesinvolved in the collection of physical evidence froma crime sceneEx. Latent fingerprints (invisible to the naked eye) aretreated with chemicals to become visible ( chemicalchange)Developing latent fingerprintsImage -Dsc 0025.jpgticles/RTX/sReference: M. Johll,Johll, “Investigating Chemistry: A Forensic SciencePerspective.” W.H.Freeman:W.H.Freeman: New York, 2007. p. 26.Collecting and Preserving EvidenceEx. Bloody clothes are dried out to prevent theblood from decomposing.decomposing. Identify the underlined words above as either aphysical or chemical change.Question: Why are evidence collected in separatecontainers?Reference: M. Johll,Johll, 2007, p. 255
7/6/2009Identifying chemical changesChemical changes are more difficult to identify than physicalchanges Can’t see changes in molecules But we can look for observable signs color change bubbling and fizzing light production smoke, and presence of 0/8th/matter/sciber/chemchng.htmEveryday life chemical changes/reactions AcidAcid--base reactionsQ. Do you know where in our body do we have acids?Q. Can you give some examples of acids? Bases?Q. Can you give an example of acidacid-base reaction?6
7/6/2009Everyday life chemical changes/reactions Oxidation reactionsQ. Can you tell which gas is used or produced duringoxidation?Q. What could be an observable sign of oxidationreaction?ACID and BASESof everyday life7
7/6/2009Image available at C. Snyder, “The ExtraordinaryChemistry of Ordinary Things,” 4th ed. Wiley, 2003.Acidic soilAlkaline (basic) soilImage available at C. Baird and W. Gloffke,Gloffke, “Chemistry InYour Life.” New York: Freeman, 2003. (p. 437)8
7/6/2009Acidic and basic are two extremes that describechemicals, just like hot and cold are two extremesthat describe temperature.Mixing acids and bases can cancel out their extremeeffects; much like mixing hot and cold water caneven out the water temperature.A substance that is neither acidic nor basic ure/ph.htmlImage available athttp://www.phsciences.com/about ph/ph scale.aspHighly corrosive!Remember:Low pH high acidityHighly corrosive!9
Physical and Chemical Changes Change is CCOOOOLL!! Physical vs. Chemical Changes Physical changes occur when substances or objects undergo a change without changing into another substance Chemical changes are changes substances undergo when they become new or different substances.
These kinds of changes are called physical changes. Physical changes are changes in the way matter looks. Changes in size and shape, like the changes in the cut pieces of paper, are physical changes. Physical changes are changes in the . Give two examples of a chemical change and EXPLAIN why they are a chemical
a change in its physical properties is called a physical change. A physical change is generally reversible. In physical change no new substance is formed. For example 1. Melting of ice into water and freezing of water into ice 2. Change of iron piece into wire or sheet 3. Lighting of bulb 4. Preparation of sugar or salt solution Chemical Change
melts (see Figure L2.1). Scientists classify changes in matter as either a chemical change or a physical change. A chemical change is defined as a change in the composition and properties of a substance. Chemical changes involve the rearrangement of molecules or atoms and result in the pro-duction of one o
In a physical change the substance involved remains the same. « Changes of state and size are physical changes. «dissolving is also a physical change. Feb 19 11:08 AM In a chemical change the original substance is changed into one or more different substances that have different properties «chemical changes always involve the production of
Chemical Formulas and Equations continued How Are Chemical Formulas Used to Write Chemical Equations? Scientists use chemical equations to describe reac-tions. A chemical equation uses chemical symbols and formulas as a short way to show what happens in a chemical reaction. A chemical equation shows that atoms are only rearranged in a chemical .
Levenspiel (2004, p. iii) has given a concise and apt description of chemical reaction engineering (CRE): Chemical reaction engineering is that engineering activity concerned with the ex-ploitation of chemical reactions on a commercial scale. Its goal is the successful design and operation of chemical reactors, and probably more than any other ac-File Size: 344KBPage Count: 56Explore further(PDF) Chemical Reaction Engineering, 3rd Edition by Octave .www.academia.edu(PDF) Elements of Chemical Reaction Engineering Fifth .www.academia.eduIntroduction to Chemical Engineering: Chemical Reaction .ethz.chFundamentals of Chemical Reactor Theory1www.seas.ucla.eduRecommended to you b
2.1 - Chemical Equations Physical and Chemical Changes Physical change: A substance changes its physical appearance, but not its composition. Example: All changes of state. Chemical change: A substance is transformed into a chemically di erent substance. Example: The burning of
koperasi, dana pensiun, persekutuan, perkumpulan, yayasan, organisasi massa, organisasi sosial politik, atau organisasi lainnya, . 12 13 Penjelasan Pasal 1 Cukup jelas. BAB II NOMOR POKOK WAJIB PAJAK, PENGUKUHAN PENGUSAHA KENA PAJAK, SURAT PEMBERITAHUAN, DAN TATA CARA PEMBAYARAN PAJAK Pasal 2 (1) Setiap Wajib Pajak yang telah memenuhi persyaratan subjektif dan objektif sesuai dengan .
