Properties of Matter Physical vs. Chemical Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Matter Matter Has both physical and chemical properties.

Physical Properties Physical properties are Characteristics observed or measured without changing the identity of a substance. Shape, state of matter, odor, conductivity, boiling and freezing points, density, solubility, and color of that substance. Can help you ID an unknown substance EX: If I freeze water, it's still water. Water boils at 100°C. NaCl is soluble in water.

Physical Properties of Copper Copper has the following physical properties: Reddish-orange Very shiny Excellent conductor of heat and electricity Solid at 25C Melting point 1083C Boiling point 2567 C Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

States of Matter The states of matter are Solid Definite volume and shape Liquid Definite volume, but take the shape of its container Gas No definite volume or shape Plasma—high energy, high temperature phase where electrons are moving (fluorescent bulb; stars) Bose-Einstein condensate—at temps close to absolute zero, matter behaves like waves and behaves oddly

Physical Properties can be Intensive or Extensive Intensive: any property that is true no matter how much of a substance is present. Ex: Density of Al Both samples of Al have same density, 2.70 g/mL, no matter how much Al is present

Physical Properties can be Intensive or Extensive Extensive: any property that is true because of the amount of substance that is present. Ex: Mass of Al The dish of Al has a mass of 142.50 g, but the pallets of Al ingots have a mass of 105.0 kg

Physical Change A physical change occurs in a substance if there is A change in the state of matter. A change in the physical shape. No change in the identity and composition of the substance.

Examples of Changes of State Some changes of state for water: Solid water (ice) melts and forms liquid water. Liquid water boils and forms gaseous water (steam). Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Examples of Physical Changes Paper torn into little pieces (change of size) Copper hammered into thin sheets (change of shape) Water poured into a glass (change of shape) Salt dissolving in water Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Learning Check Classify each of the following as a 1) change of state 2) change of shape A. Chopping a log into kindling B. Water boiling in a pot C. Ice cream melting D. Ice forming in a freezer E. Cutting dough into strips

Solution Classify each of the following as a 1) change of state 2) change of shape A. (2) Chopping a log into kindling B. (1) Water boiling in a pot C. (1) Ice cream melting D. (1) Ice forming in a freezer E. (2) Cutting dough into strips

Chemical Properties Chemical properties describe the ability of a substance To react with other substances and to become something new. …flammability, reactivity, corrosiveness are examples Example: Iron has the ability to form rust (iron oxide) when exposed to oxygen. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Learning Check Classify each of the following properties as physical or chemical: A. Ice melts in the sun B. Copper is a shiny metal C. Paper can burn D. A silver knife can tarnish E. A magnet removes iron particles from a mixture

Solution Classify each of the following properties as physical or chemical: A. Ice melts in the sun (physical) B. Copper is a shiny metal (physical) C. Paper can burn (chemical) D. A silver knife can tarnish (chemical) E. A magnet removes iron particles from a mixture (physical)

Chemical Change In a chemical change, a new substance forms that has… A new composition (atoms are rearranged) New chemical and physical properties when compared to the original substance/s. What clues indicate this???????? Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Chemical Change Indicators Unexpected Color Change Precipitate (solid that forms when two aqueous solutions combine) Gas production (bubbles produced) Temperature change-(Be careful!! This one by itself can’t be trusted) Light given off

Some Chemical Changes Silver tarnishes Shiny metal reacts to form black, grainy coating. Wood burns A piece of wood burns with a bright flame to form ash, carbon dioxide, water vapor, and heat. Iron rusts A shiny nail combines with oxygen to form orange-red rust.

Learning Check Classify each of the following changes as physical or chemical A. Burning a candle. B. Ice melting on the street. C. Toasting a marshmallow. D. Cutting a pizza. E. Iron rusting in an old car

Solution Classify each of the following changes as physical or chemical A. Burning a candle. (chemical) B. Ice melting on the street. (physical) C. Toasting a marshmallow. (chemical) D. Cutting a pizza. (physical) E. Iron rusting in an old car. (chemical)