Descriptive Properties of

Matter

Include two types of ObservationsInclude two types of Observations

QualitativeQualitative• Gives results in a description, nonumerical Gives results in a description, nonumerical

formform

QuantitativeQuantitative• Give results in a definite form, usually Give results in a definite form, usually

numbers and unitsnumbers and units

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

Accuracy vs. Precision

Density

MassVolume

Density =

What are the units for each?gmL

g/mL

Types of Values• Accepted Value – the ‘book’ value, what the

value is supposed to be.• Experimental Value – the value found in the

lab.

Percent Error• Indicates accuracy of a measurement

100literature

literaturealexperimenterror %

your value accepted value• 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.

100g/mL 1.36

g/mL 1.36g/mL 1.40error %

% error = 2.9 %

• Physical Property - can be observed without changing 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 without changing 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?

Differences between Mass and Weight

Mass Weight

1. Is always a constant at any place and time

Depends on gravity at the place

2. Is measured in kilograms in SI unit Is measured in Newtons (not in kilograms as one might think)

3. Is measured using balance Is measured using scales

4. Can never be zero Can also be zero

5. Is an intrinsic property of a body and is independent of any external factor.

Depends on 1. Mass of the object which is attracting it 2. Force with which it is being attracted (which in turn depends on the distance between the two)

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.

Matter’s Changes and Properties

• Physical Property– can be observed without changing

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

There are properties that are used to describe matter.

Density Problems1. What is the volume of a tank that can hold

754 g of methanol whose density is 0.788 g/cm3?

2. 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?

3. The density of silver at 20ºC is 10.5 g/cm3. What is the volume of a 68 g bar of silver?