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Descriptive Properties of. Matter. Qualitative Gives results in a description, nonumerical form. Quantitative Give results in a definite form, usually numbers and units. Include two types of Observations. Accuracy vs. Precision. Accuracy - how close a measurement is to the accepted value
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Descriptive Properties of Matter
Qualitative Gives results in a description, nonumerical form Quantitative Give results in a definite form, usually numbers and units Include two types of Observations
Accuracy vs. Precision • Accuracy- how close a measurement is to the accepted value • Precision - how close a series of measurements are to each other ACCURATE = CORRECT PRECISE = CONSISTENT
Density What are the units for each? g Mass Volume g/mL Density = Types of Values mL • Accepted Value – the ‘book’ value, what the value is supposed to be. • Experimental Value – the value found in the lab.
your value accepted value Percent Error • Indicates accuracy of a measurement • A student determines the density of a substance to be 1.40 g/mL. Find the % error if the accepted value of the density is 1.36 g/mL. % error = 2.9 %
Physical Property - can be observed withoutchanging the identity of the substance • Extensive property – physical property that depends on the amount of the substance • Examples: mass, volume, length • Intensive property – physical property that is not dependent of the amount of substance. • Examples: Density, color, melting point • Chemical Property – often can not be observed withoutchanging the identity of the substance; involves electrons at the atomic level
Classification of Matter • Matter is anything that has a mass and volume. • Mass is the amount of matter the object contains. • Volume is the amount of space an object takes up. • Examples of things that are not matter: • Light and energy • Picture a Golf Ball and a Ping Pong Ball… Which has more mass? More volume?
States of Matter • Solid – definite shape, definite volume; little movement of particles. • Liquid – indefinite shape, definite volume; some movement of particles. • Gas – indefinite shape, indefinite volume; lots of movement of particles.
Physical Property can be observed withoutchanging the identity of the substance color texture density viscosity change in state solubility malleability mass volume Chemical Property describes the ability of a substance to undergo changes in identity A new substance is produced reactivity toxicity pH conductivity tarnishing fermenting Oxidation flammability Matter’s Changes and Properties There are properties that are used to describe matter.
Density Problems • What is the volume of a tank that can hold 754 g of methanol whose density is 0.788 g/cm3? • What is the density of a board whose dimensions are 5.54 cm x 10.6 cm X 19.9 cm and whose mass is 28.6 Kg? • The density of silver at 20ºC is 10.5 g/cm3. What is the volume of a 68 g bar of silver?