Matter

Properties

http://z.about.com/d/chemistry/1/0/x/c/transitionmetalsolns.jpg

So What is Matter?

• Anything that occupies space and has mass

What isn’t matter?• Energy• Ideas, gravity, shadows…

Properties

• Physical Property - any property that can be observed without transforming the substance into another substance

mass, color, freezing point• Chemical Property - any property that cannot

be studied without transforming the substance into a different substance

iron rusts, paper burns

Properties• Intrinsic property– does not depend on the

amount of material you havecolor, solubility, viscosity, malleability, boiling point

• Extrinsic property – depends on the amount of mattermass, volume, length

What is density?

Density

• Property derived from two measurements, mass and volume

• Density = Mass/Volume• Will have a unit that contains both mass and

volume such as g/cm3, lb/gal, kg/L• Does not depend on the size of the sample

Density

• What is the density of a sample of metal that has a mass of 34.58 g and when placed in 15.0 mL of water causes the level to rise to 22.4 mL?

34.58 gMD = = = 4.7 g/ mL

V 7.4 mL

22.4 mL - 15.0 mL = 7.4 mL

CHM 1010 PGCC Barbara A. Gage

Changes

• Physical Change - change that does not transform the substance into another substancemelting, subliming, dissolving

Physical Changes

• What were the physical changes that you encountered in the activities on Day 2?

Splint broken into piecesNaCl dissolved in waterSand and salt mixedAlum heated and cooled

Changes• Chemical Change - change that transforms

one substance into another substanceburning,oxidation of metal precipitation of solid

Chemical Changes

• What were the chemical changes you encountered on Day 2?

Burning of ethanol Heating CuCO3

Reaction of cobalt chloride and sodium phosphateBurning splint Ethanol and KMnO4

Chemical Change

CHM 1010 PGCC Barbara A. Gage

From Silberberg, Principles of Chemistry, 2007

Distinguishing Between Physical and Chemical Changes

PROBLEM: Decide whether each of the following process is primarily a physical or a chemical change, and explain briefly:

SOLUTION:

(a) Frost forms as the temperature drops on a humid winter night.(b) A cornstalk grows from a seed that is watered and fertilized.(c) Dynamite explodes to form a mixture of gases.

(d) Perspiration evaporates when you relax after jogging.

(e) A silver fork tarnishes slowly in air.

(a) physical change

(b) chemical change

(c) chemical change

(d) physical change

(e) chemical change