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By the end of this section, you will be able to:
  • Identify properties of and changes in matter as physical or chemical
  • Identify properties of matter as extensive or intensive

The characteristics that enable us to distinguish one substance from another are called properties. A physical property    is a characteristic of matter that is not associated with a change in its chemical composition. Familiar examples of physical properties include density, color, hardness, melting and boiling points, and electrical conductivity. We can observe some physical properties, such as density and color, without changing the physical state of the matter observed. Other physical properties, such as the melting temperature of iron or the freezing temperature of water, can only be observed as matter undergoes a physical change. A physical change    is a change in the state or properties of matter without any accompanying change in its chemical composition (the identities of the substances contained in the matter). We observe a physical change when wax melts, when sugar dissolves in coffee, and when steam condenses into liquid water ( [link] ). Other examples of physical changes include magnetizing and demagnetizing metals (as is done with common antitheft security tags) and grinding solids into powders (which can sometimes yield noticeable changes in color). In each of these examples, there is a change in the physical state, form, or properties of the substance, but no change in its chemical composition.

Figure A is a photograph of 5 brightly burning candles. The wax of the candles has melted. Figure B is a photograph of something being heated on a stove in a pot. Water droplets are forming on the underside of a glass cover that has been placed over the pot.
(a) Wax undergoes a physical change when solid wax is heated and forms liquid wax. (b) Steam condensing inside a cooking pot is a physical change, as water vapor is changed into liquid water. (credit a: modification of work by “95jb14”/Wikimedia Commons; credit b: modification of work by “mjneuby”/Flickr)

The change of one type of matter into another type (or the inability to change) is a chemical property    . Examples of chemical properties include flammability, toxicity, acidity, reactivity (many types), and heat of combustion. Iron, for example, combines with oxygen in the presence of water to form rust; chromium does not oxidize ( [link] ). Nitroglycerin is very dangerous because it explodes easily; neon poses almost no hazard because it is very unreactive.

Figure A is a photo of metal machinery that is now mostly covered with reddish orange rust. Figure B shows the silver colored chrome parts of a motorcycle. One of the parts is so shiny that you can see a reflection of the surrounding street and buildings.
(a) One of the chemical properties of iron is that it rusts; (b) one of the chemical properties of chromium is that it does not. (credit a: modification of work by Tony Hisgett; credit b: modification of work by “Atoma”/Wikimedia Commons)

To identify a chemical property, we look for a chemical change. A chemical change    always produces one or more types of matter that differ from the matter present before the change. The formation of rust is a chemical change because rust is a different kind of matter than the iron, oxygen, and water present before the rust formed. The explosion of nitroglycerin is a chemical change because the gases produced are very different kinds of matter from the original substance. Other examples of chemical changes include reactions that are performed in a lab (such as copper reacting with nitric acid), all forms of combustion (burning), and food being cooked, digested, or rotting ( [link] ).

Questions & Answers

how do I get MCQs and essay to work?
Jake Reply
I want spectroscopy
Nipun
Check on play store Maybe you'll get an app for that
Idrissa
what is electrolysis
lola Reply
state the periodic law
Kelly Reply
the modern periodic state dat element are arranged in row and column according to their atomic number
lola
what is chemistry
sullayman Reply
chemistry is the brach of science which deal with composition and dicomposion of matter
ezekier
What are the branchs of chemistry
Blessing
What is matter
Believe Reply
matter is anything that has mass or weight and accopies space
ezekier
what is endothermic
Yemi Reply
something that absorbs some form energy
mohammed
What is gas law
Clement Reply
law is the rule of government
Dawite
gas law I have no idea
Israel
There are different Gas Laws There's boyles law, Charles law... Etc
Kanji
can you be more specific
Allyson
wat is hydroxyl
James
why is borontrihydride considered a Lewis acid
Mmesoma Reply
electronic configuration
Elabo Reply
What is chemistry
Blessing Reply
it's is a branch of science that deals with the nature and composition of various matters and how the under go changes
Kelly
Pls what is the structural formula for propanonitrile
Olaiya Reply
chemistry is the study of the interaction, structure and properties of matter
Olaiya
If a man has a mass of 115 pounds,what is his mass in gram lb=453.6g?
Henok
chemistry laboratory apparatus
yusuf Reply
pica.flitter paper,conical flasks
Gift
Burette,pipette,Bunsen burner,test tube
Olaiya
what is chemistry
John Reply
study of chemicals and their reactions
salma
study of matter nd there compound
Gift
study of matter
Cypha
explain the fazan's law and explain its application
nidhi Reply
what is a solute
Gbagede Reply
substance that allows another substance to mix freely on it eg water
Mercy
solute ar substance which dissolve in solvent eg sucrose
Aham
It dissolves in a solvent
Sandy
Someone who tries to convert base metals into gold 🌟
Sandy
Sorry
Sandy
solute is a solid elements.mixed with solvent to give us solution
Gift
solute are dissolved substance which may be a solid, liquid or gas
Adeosun
what is polymerization
Adeosun
solute are sub dat a.llow solvent dissolve in themmk.j
lola
The minor component in a solution, dissolved in the solvent
Mmesoma
Practice Key Terms 6

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Source:  OpenStax, Chemistry. OpenStax CNX. May 20, 2015 Download for free at http://legacy.cnx.org/content/col11760/1.9
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