Understanding Matter: Characteristics, Classification, and Changes in Physical States
Matter is the substance that occupies space and has mass, distinct from weight, which is the gravitational force acting on it. This guide explores the classification of matter based on physical state (solid, liquid, gas) and composition (substance, mixture). It highlights the unique properties of solids, liquids, and gases, explaining how matter can change states and the difference between compounds and molecules. With references to authoritative chemistry texts, this overview serves as a foundational understanding of matter in the universe.
Understanding Matter: Characteristics, Classification, and Changes in Physical States
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Matter occupies space and has mass Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Mass is different from weight • mass is the measure of the quantity of matter in an object • weight is the force that gravity exerts on an object • astronaut’s mass • = 50 kg • astronaut’s weightearth • = 50 kg * 9.8 m/s2 Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
On the moon, astronauts feel weightless • weightmoon = 1/6 weightearth http://grin.hq.nasa.gov/IMAGES/SMALL/GPN-2002-000146.jpg
There are different ways to classify matter • based on physical state (solid, liquid, gas) • based on composition (substance, mixture) Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Classification of matterbased on physical state(solid, liquid, gas)
Properties of a solid • retains its own shape and volume • virtually incompressible • does not flow ? Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Properties of a liquid • assumes the shape of the container • does not expand to fill container • virtually incompressible • flows readily Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Properties of a gas • assumes both the volume and shape of the container • compressible • flows readily Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Matter can change from one physical state to another Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
* Energy is the capacity to do work or to produce change. It may take different forms, and heat is one of them. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Classification of matterbased on composition(substance, mixture) Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
A substance has definite or fixed composition which does not vary from one sample to another gold water Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Substances are further classified into two: elements and compounds Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Elements are composed entirely of one type of atom Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd. Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Compounds are made up of two or more different kinds of atoms that are combined in fixed ratios Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd. Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Note: There is a difference between a compound and a molecule • compound • made up of two or more different kinds of atoms joined together Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Note: There is a difference between a compound and a molecule • molecule • made up of two or more atoms joined together • the atoms may be the same or different Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd. Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
A mixture has a composition that may vary from one sample to another silver and gold silver and gold in water Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Mixtures are further classified into two: homogeneous and heterogeneous Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Homogeneous mixture has the same composition and properties throughout the solution Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Heterogeneous mixturevaries in composition and/or properties from one part of the mixture to another Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
Brown, , E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. Phils: Pearson Education Asia Pte. Ltd.
The properties of matter can be given in two ways • extensive or intensive property • physical or chemical property
Extensive property depends on the amount of matter being considered • values of the same extensive property may be added together Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc. www.swapmeetdave.com/Humor/Cats/CatOnScale.jpg
Intensive property does not depend on the amount of matter being considered • values of the same intensive property may not be added together • extensive / extensive = intensive Hill, J. and Petrucci, R. 1996. General Chemistry Instructor’s Edition.USA: Prentice-Hall, Inc.
For next week meeting • Bring your scientific calculator
Physical propertycan be measuredwithout altering the composition or identity of a substance • physical change: only alters the physical make-up of a substance Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
Chemical property cannot be measured without converting the substance into some other substance • chemical change: changes the chemical make-up of a substance Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.
