Introduction Chemistry: The study of matter and its changes Chemistry investigates and explains the...

Introduction

Chemistry:The study of matter and its changes

Chemistry investigates and explains the sub-microscopic reasons for the what happens in the macroscopic world!

Introduction

Sub-microscopic understanding leads to understanding of the world around you:

How does bleach remove stains?

What causes and air bag to inflate?

Why does DNA have a double helical structure?

What makes a rose smell sweet and old fish smell awful?

Introduction

How does radio-carbon dating tell how old a fossil is?

What are electrolytes and why do sports drinks like Gatorade contain them?

What happens to garbage in a landfill? Is it always better to use biodegradable materials?

Introduction

Why should YOU study chemistry?

PsychologyEnglishBSW/MSWFine ArtsPre-Law

Required for your college major

Pre-medPre-pharmacyPre-dentalBiologyGeologyEnvironmental ScienceEngineeringNursing

IntroductionChemistry is the foundation of other sciences

Physics Biology Geology Astronomy

Chemistry impacts our daily lives! Food, clothing and shelter Health care Environment Life itself

Measurement

Metric System

s second Time

K or o C Kelvin or

degree celsiusTemperature

Lliter Volume

g gram Mass

m meterLength

Unit Symbol UnitQuantity

Prefixes

ExampleMeans..SymbolPrefix

cghundredthc centi-

gmillionthmicro-

kmthousandkkilo-

mLthousandthmmilli-

every student should know…

More prefixes…

GAGgiga-

MLmillionmega- M

couldn’t hurt to know these ones, too:

thousand million

ExampleMeans..SymbolPrefix

Benefits of the Metric System:

• Uses Decimal System• International Standard• The units relate to

each other by using water as standard!

(What does that mean?)

“the units relate to each other…

1cm3 = 1 mL

therefore , (10cm)3 = 1 L

1000 cm3 = 1 L

http://www.metricamerica.com

…by using water as a standard”:

1 kg H2O ≈ 1 L H2O ≈ (10 cm)3 H2O ≈ 1000 cm3 H2O

http://www.metricamerica.com/images/Export00_288.mov

1g H2O ≈ 1 mL H2O

Volume is special

because:

• Volume can be measured in

liters (L),

milliliters (mL), etc. s

or…

OR…

• Volume can be measured in

cubic meters (m3)

centimeters (cm3),

…..etc.

Remember;

1 cm1 cm3 3 = 1 mL = 1 mL

Remember any geometry?• Volume of a cube is ….

l x w x hi.e. 4cm x 5cm x 2cm = 40 cm3

i.e. x (5cm)2 x 10cm = 250 cm3

•Volume of a cylinder is ….

r2 h

Typically,

mL or L are used to describe the volume of a liquid...

…and cm3 or m3 are used to describe the volume of a regularly shaped solid.

Volume of a Rock…To find the volume of objects with weird shapes,

use a technique called “water displacement”

in this case,the volume of the solid may be in

cm3 or mLRemember:

1 cm1 cm3 3 = 1 mL = 1 mL

Determining the Volume of an Irregularly Shaped Solid

22 mL 32 mL

Temperature is special because…

We will sometimes use degrees celsius…

…we sometimes will use kelvin.

Absolute Zero

Freezing Point of Water

Body Temperature

Boiling Point of Water

-459 O

32 O

98 O

212 O

F

-273 o

0 O

37 O

100 O

C

0

273

310

373

KExample

Meters, Liters, Grams, Seconds….

These are units you should be familiar with.

In chemistry,we will use math to do weird things to these nice units…

…and turn them into units that are complex.

Complex units like….

g/mL and kg•m/s2

Math with Units…

5 • 5 = 25

3m • 4m =

4 kg • 2 m/s2 =

10 L•atm ÷ 2 mol•K = 5(L•atm)/(mol•K)

8 kg•m/s2

12 m2

Examples:

12m2 ÷ 12m = 1m

Example: DensityDensity is a property of matter. If you measure the mass and the volume of an object, you can calculate it’s density using the formula:

(g) (mL)

D = m/v

Density = mass/volumeSo, the units of density must be…. g/mL

Complex Units come from a formula…

• Why is density measured in g/mL?

Because the formula for density is

(aka “grams per milliliter”) (not “gee slash em-ell”)

m mass (in grams) g

D = ----- = ------------ -------------- ----

v volume (in milliliters) mL

DENSITYDENSITYStyrofoamStyrofoam BrickBrick

Brick is more dense than Styrofoam because there is

more mass

packed into the

same volume

(more molecules or atoms in the same space.)

Substance Density (g/mL)

 • Air 0.0013 g/mL

• Wood (Oak) 0.80 g/mL

• Steel  7.80 g/mL

•Water  1.00 g/mL

Density of Gold:

19.30 g/mL

Silver:

10.50 g/mL

Aluminum:  2.70 g/mL

Atoms of some elements are more dense Atoms of some elements are more dense than others. than others.

DENSITY - an important and useful physical property

Density mass (g)volume (cm3)

Density mass (g)volume (cm3)

13.6 g/cm13.6 g/cm33 21.5 g/cm21.5 g/cm33

Aluminum

2.7 g/cm2.7 g/cm33

PlatinumMercury

Variations of the Density Formula:

D = m/v

v = m/D

m = v • D

D v

m

Application:

Calculate the density of a 57.9g sample of metal with a volume of 22.45mL.

Application:

• Calculate the mass of 4,800 mL of molten lead (density = 11.4g/mL)?

•What is the mass in kg?

Application:

• A camelbak backpack hold 1 kg of water. What is the volume of the backpack?

Application:

• Molten iron (Fe) has a known density of 7.87 g/cm3.  What would be the volume of 595 kg of molten iron, in liters?

Metric System

s second Time

K or o C Kelvin or

degree celsiusTemperature

Lliter Volume

g gram Mass

m meterLength

Unit Symbol UnitQuantity

Prefixes

ExampleMeans..SymbolPrefix

cghundredthc centi-

gmillionthmicro-

kmthousandkkilo-

mLthousandthmmilli-

every student should know…

Typically,

mL or L are used to describe the volume of a liquid...

…and cm3 or m3 are used to describe the volume of a regularly shaped solid.

Temperature is special because…

We will sometimes use degrees celsius…

…we sometimes will use kelvin.

Absolute Zero

Freezing Point of Water

Body Temperature

Boiling Point of Water

-459 O

32 O

98 O

212 O

F

-273 o

0 O

37 O

100 O

C

0

273

310

373

KExample

Example: DensityDensity is a property of matter. If you measure the mass and the volume of an object, you can calculate it’s density using the formula:

(g) (mL)

D = m/v

Density = mass/volumeSo, the units of density must be…. g/mL