Matter and Density

Stating a Measurement

In every measurement there is a

¨ Number followed by a

¨ Unit from a measuring device

International System of Units (SI)adopted in 1960seven base units which all others can

be derivedm, kg, K, s, mol, cd, A

SI measurementLe Système international

d'unités The only countries that have

not officially adopted SI are Liberia (in western Africa) and Myanmar (a.k.a. Burma, in SE Asia), but now these are reportedly using metric regularly

Metrication is a process that does not happen all at once, but is rather a process that happens over time.

Among countries with non-metric usage, the U.S. is the only country significantly holding out. The U.S. officially adopted SI in 1866.

Information from U.S. Metric Association

Common Metric Prefixes

properties are that it has:mass: amount of matter (atoms) in an object

volume: amount of space an object takes up

density: the mass per unit volume of an object

Matter

What some things that are not matter?

Lengtha linear measurementmeter (m)common units- cm, m, km

Volumespace occupied by a sample of mattercubic meter (m3) but we use the non SI

unit liter (L) most of the time insteadcommon units- L, ml, cm3, µLshould be measured at 0°C

Massthis in NOT weight

measures the quantity of matter

kilogram (kg)common units- kg, g, mg, µg

Temperaturemeasures kinetic energy of particleskelvin (K)common units are K and °C

Anders Celsius1701-1744

Lord Kelvin(William Thomson)1824-1907

Notice that 1 Kelvin = 1 degree Celsius

Learning Check

Match L) length M) mass V) volume

____ A. A bag of tomatoes is 4.6 kg.

____ B. A person is 2.0 m tall.

____ C. A medication contains 0.50 g

Aspirin.

____ D. A bottle contains 1.5 L of

water.

M

L

M

V

Densityan intensive or intrinsic property of matter

the ratio of an object’s mass to its volume

depends on only on the substance, NOT ON THE SIZE of the substance

as temperature increases, density normally decreases (thermal expansion)

Back to the

Future “Your are

my density”

clip. Back to the Future

“Your are my

density” clip

Density

D = densityM = massV = volume

D = M/V

Example problem• A piece of lead has a mass of 56.4 g and

a volume of 5.3 cm3. Calculate its density.

M= 56.4 g D=M/VV= 5.3 cm3

given formula set up problem answer w/ unit of measurement

cm3 is same as ml so sometimes see g/ml

56.4g/5.3 cm3 11 g/cm3

Density mass (g)volume (cm3)

Density mass (g)volume (cm3)

Mercury

13.6 g/cm3 21.5 g/cm3

Aluminum

2.7 g/cm3

Platinum