Chemical or Physical Change Vocabulary chemistry matter physical property chemical property physical change chemical change evidence of chemical change s olid liquid g as precipitate ID: 548534
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Chemical or Physical Property?Chemical or Physical Change?
Vocabulary:
chemistrymatterphysical propertychemical propertyphysical changechemical changeevidence of chemical changesolidliquidgasprecipitatemicroscopicmacroscopic
“Persistence of Memory” 1931
Salvador DaliSlide2
The study of matter (anything that has mass and takes up space) and changes it undergoes.
What is chemistry?Slide3
Let’s distinguish between a property and a change.
Property:A quality or trait belonging to a substance.Static (unchanging.)
Before we begin…Change:To make different in some way.Dynamic (changing)Slide4
Characteristic that can be observed without changing the identity of the substance.
Physical
PropertyExamples: melting pointboiling pointcolorelectrical conductivitydensityhardnessshapemalleabilitySlide5
Ability of a substance to undergo a change that transforms it into a different substance.
Chemical Property
Examples: flammabilityfermentabilityreactivity with acidsrustabilitySlide6
A change in a substance that does not involve a change in the identity of the substance.
Physical ChangeSlide7
Phase changes such as…Physical Change Examples
melting (solid to liquid)
boiling (liquid to gas)freezing (liquid to solid)sublimating (solid to gas)Slide8
What are the phases (or states) of matter?Speaking of phase changes…
Gases
Properties:flow easily (macroscopic) - particles can move/slide past one another (microscopic)takes the shape and volume of container (macroscopic)easily compressible (macroscopic) because there is a lot of space between particles (microscopic)AsSlide9
What are the phases (or states) of matter?Speaking of phase changes…
Liquids
Properties:flow easily (macroscopic) - particles can move/slide past one another (microscopic)have a fixed volume but take shape of container (macroscopic)not easily compressible (macroscopic) because there is very little space between particles (microscopic)Slide10
What are the phases (or states) of matter?Speaking of phase changes…
Solids
Properties:rigid (macroscopic) - particles cannot move/slide past one another (microscopic)have a fixed volume and shape (macroscopic)not easily compressible (macroscopic) because there is very little space between particles (microscopic)Slide11
More Physical Change Examples
mixture separation
dissolvingcuttingSlide12
A change in which one or more substances are converted into different substances. (There is a new substance!!!!!!!)
Chemical ChangeSlide13
Examine each of the following pictures and identify evidence of chemical change.
How can you tell if a chemical change has occurred?Slide14
Chemical Change ExamplesSlide15
Evidences of a chemical change (i.e., the formation of a new substance):Color changeChange in energy (
hotter, colder, or light)Formation of a gasFormation of a precipitateChemical ChangeSlide16
What is a precipitate?A solid that comes out of solution in a chemical reaction.
PrecipitateSlide17
Identify each of the following examples as a physical property, chemical property, physical change, or chemical change. Give evidence for your answer!
Practice!Slide18
Melting candle waxphysical change (no new substance formed; solid to liquid wax)Burning wood
chemical change (new substance formed; color change, gas produced, heat produced)Dissolving salt in waterphysical change (no new substance formed; salt can be easily recovered, did not turn into something new)
Practice!Slide19
Tearing a piece of paperphysical change (no new substance formed; different form of same substance)An egg yolk is yellow
physical property (characteristic of the substance; can be observed without changing the substance)Magnesium can react with acidchemical property (characteristic of the substance; must change the substance to observe the characteristic)
Practice!Slide20
Baking breadchemical change (new substance formed; color change, gas produced)What type of change seems to be taking place in the picture below?
physical change (objects are melting but not changing into new substances)
Practice!Slide21
There are some different types of matter that chemists deal with daily.Elements: These are the simplest forms of matter. The smallest particles of elements are called atoms. Elements can not be separated into simpler substances. All of the elements can be found on the periodic table.
Types of MatterSlide22
There are some different types of matter that chemists deal with daily.2) Compounds: Compounds are made up of the atoms of different elements bonded together. For example, water is made up of 2 hydrogen atoms bonded to 1 oxygen atom. Compounds can be broken apart into their elements, but only through a chemical change because bonds must be broken and one or more new substances are formed. The smallest particles of a compound are
called molecules.Types of MatterSlide23
There are some different types of matter that chemists deal with daily.3) Mixtures: Mixtures are combinations of different substances that are not chemically bonded. For instance, salt mixed with pepper, a salad, and salt dissolved in water are all examples of mixtures. Separating a mixture only requires a physical change since bonds to not need to be broken and new substances are not formed.
Types of Matter