Presentation on theme: "Physical versus Chemical Properties & Changes"— Presentation transcript:
1 Physical versus Chemical Properties & Changes Chapter 1 – Section 3Changes in Matter
2 Reviewing MATTER Matter: anything that has mass and takes up space Mass – the amount of matter in somethingVolume – the amount of space something occupiesWhich of the following is matter?A car?A box?You?
3 What is a property? CHARACTERISTIC PROPERTY: A characteristic of a substance that can be observed and/or measured
4 What are characteristic properties good for? We can use these properties to identify substances.2 basic types of properties of matter:PHYSICAL and CHEMICALALWAYS the same whether object is large or small
5 Physical PropertyPHYSICAL PROPERTY: A property that can be observed WITHOUT CHANGING the identity of the substance.A feature of a substance that does NOT involve a chemical change.Same substance, same compounds you started with.
7 Chemical Property CHEMICAL PROPERTY: A property that can only be observed by CHANGING the identity of the substance.Characteristics that indicate if a material can undergo a certain chemical change.A property of matter that describes its ability to be involved in chemical reactions.Chemical properties can ONLY be observed AS the substances are changing into different substances.
8 Chemical Property Examples: * Flammability (Combustibility)– ability to burn* Ability to rust from oxygen* Reactivity with water or vinegar* Toxicity- how dangerous the material is* Radioactivity- does the material give off radiation* Sensitivity to light- how sensitive the material is when placed under a light or the sun8
9 Physical ChangesPhysical changes are those changes that DO NOT result in the production of a new substance. If you melt a block of ice (frozen H2O), you still have H2O at the end of the change.
10 Physical ChangesIf you break a bottle, you still have glass. Painting your nails will not stop them from being fingernails. Some common examples of physical changes are: melting, freezing, condensing, breaking, crushing, cutting, and bending.
11 Physical ChangesAffects one or more physical properties of a substance, but not chemical properties or identity of a substance (appearance affected, but not composition)
12 Physical ChangesSome, but not all physical changes can be reversed. You could refreeze the water into ice, but you cannot put your hair back together if you don’t like your haircut!
13 Chemical ChangesChemical changes, or chemical reactions, are changes that result in the production of another substance.Occurs when 1 or more substances change into entirely new substances with different characteristic properties.Cannot reverse chemical changes using physical means, sometimes cannot reverse at all
14 Chemical ChangesCommon examples of chemical changes that you may be somewhat familiar with are: digestion, respiration, photosynthesis, burning, and decomposition.
15 FLAMMABILITY: A material’s ability to BURN in the presence of OXYGEN Chemical ChangesFLAMMABILITY: A material’s ability to BURN in the presence of OXYGEN
16 Chemical ChangesWhen you burn a log in a fireplace, you are carrying out a chemical reaction that releases carbon. When you light a candle at home, you are carrying out a chemical reaction that produces carbon (soot) and carbon dioxide gas.
17 Chemical ChangesREACTIVITY: How readily (easily) a substance combines chemically with other substances.
18 Clues to Chemical Changes Dramatic color change (can’t use this alone!) Fizzing, foaming (new production of gas) Precipitate (new production of solid substance) Production or use of energy (light, heat) Production of sound, odor