HAVE YOU EVER WONDERED

Why the stars shine?

Why ice melts and water evaporates?

Why do leaves turn colors in the fall, and

how does a battery generate electricity?

Why does keeping foods cold slow their

spoilage, and how do our bodies use food to

maintain life?

Chemistry is the study of matters and the changes it undergoes.

How do chemical principles operate in all aspects of our lives?

CHEMISTRY

IS…

Chemistry is the study of the properties and behavior of matter.

Matter: the physical material of the universe;

anything that has mass and occupies space Property: any characteristic that allows us to

recognize a particular type of matter and to distinguish it from other types

Elements: basic substances that comprise matters Atoms: infinitesimally small building blocks of matter Molecules: matters in which two or more atoms are

joined together in specific shapes

1.1 THE STUDY OF CHEMISTRYTHE ATOMIC AND MOLECULAR PERSPECTIVE OF

CHEMISTRY

1.1 THE STUDY OF CHEMISTRYTHE ATOMIC AND MOLECULAR PERSPECTIVE OF

CHEMISTRY

To satisfy our curiosity?

Because it is an essential part of your curriculum?

To understand our world and how it works

1.1 THE STUDY OF CHEMISTRY

WHY STUDY CHEMISTRY?

FIGURE 1.2 Chemistry helps us understand the world around us.

To improve health care

To provide our everyday

needs for food, clothing,

and shelter

Chemistry helps us better

understand materials

The central science

1.1 THE STUDY OF CHEMISTRY

WHY STUDY CHEMISTRY?

Worldwide sales of chemical products: $550 billion/yr (U.S.)

Chemical industry employs >10% of all scientists/engineers

no fixed volumeno shape

fixed volumeno shape

fixed volumeand shape

1.2 CLASSIFICATIONS OF MATTER

STATES OF MATTER

Matter that has distinct properties and a composition

that does not vary from sample to sample.

(water & NaCl)

Element, compound, and mixture

1.2 CLASSIFICATIONS OF MATTER

PURE SUBSTANCES

Only one kind of atom is in any element Compounds must have at least two kinds of atoms

Pure chemical substances consisting of one type

of atom

118 elements are known (March 2010)

1.2 CLASSIFICATIONS OF MATTER

ELEMENTS

Pure chemical substances consisting of

two or more elements:

contain two or more kinds

of atoms

1.2 CLASSIFICATIONS OF MATTER

COMPOUNDS

1.2 CLASSIFICATIONS OF MATTERCOMPOUNDS

The properties of water bear no resemblance to the properties of its component elements

Heterogeneous mixtures do not have the same composition, properties, and appearance throughout

Homogeneous mixtures have the same composition, properties, and appearance throughout (solutions)

1.2 CLASSIFICATIONS OF MATTER

MIXTURES

Copper sulfateRock

1.2 CLASSIFICATIONS OF MATTER

Sample Exercise 1.1 Distinguishing among Elements, Compounds, and Mixtures

homogeneous mixture.

Solution

“White gold” contains gold and a “white” metal, such as palladium. Two samples of white gold differ in the relative amounts of gold and palladium they contain. Both samples are uniform in composition throughout. Use Figure 1.9 to classify white gold.

Aspirin is composed of 60.0% carbon, 4.5% hydrogen, and 35.5% oxygen by mass, regardless of its source. Use Figure 1.9 to classify aspirin.

Practice Exercise

Answer: compound

Physical Properties…

• Can be observed without changing a substance into another

substance.

• Boiling point, density, mass, volume, etc.

Chemical Properties…

• Can only be observed when a substance is changed into

another substance.

• Flammability, corrosiveness, reactivity with acid, etc.

1.3 PROPERTIES OF MATTER

TYPES OF PROPERTIES

Intensive Properties…

• Are independent of the amount of the substance that is

present.

• Temperature, density, boiling point, color, etc.

Extensive Properties…

• Depend upon the amount of the substance present.

• Mass, volume, etc.

1.3 PROPERTIES OF MATTER

TYPES OF PROPERTIES

Physical Changes

• These are changes in matter that do not change the

composition of a substance.

• Changes of state, temperature, volume, etc.

Chemical Changes

• Chemical changes result in new substances.

• Combustion, oxidation, decomposition, etc.

1.3 PROPERTIES OF MATTER

TYPES OF PROPERTIES

1.3 PROPERTIES OF MATTERPHYSICAL AND CHEMICAL CHANGES

FIGURE 1.10 A chemical reaction

1.3 PROPERTIES OF MATTERPHYSICAL AND CHEMICAL CHANGES

FIGURE 1.11 The chemical reaction between a copper penny and nitric acid

In filtration, solid substances are separated from

liquids and solutions.

Salt / copper

1.3 PROPERTIES OF MATTERSEPARATION OF MIXTURES

FIGURE 1.12 Separation by filtration

Distillation uses differences in the boiling points of

substances to separate a homogeneous mixture into

its components.

1.3 PROPERTIES OF MATTERSEPARATION OF MIXTURES

FIGURE 1.13 Distillation

• The differing abilities of substances to interact with the surfaces of various solids such as paper and starch can be used to separate mixtures.

Chromatography

1.3 PROPERTIES OF MATTERSEPARATION OF MIXTURES

FIGURE 1.14 Separation of ink into components

The metric system

• An international system

of measurement, first

adopted by France in

1791, that is the

common system of

measuring units used by

most of the world.

1.4 UNITS OF MEASUREMENTTHE METRIC SYSTEM AND SI UNITS

FIGURE 1.15 Metric units. Fluid ounces (fl oz), English units; mL, metric units

1.4 UNITS OF MEASUREMENTSI UNITS

The world's most widely used system of

measurement, both in everyday commerce and in

science.

From seven base units, all other units are derived

1.4 UNITS OF MEASUREMENTSI UNITS

Length and mass

• The SI base units of length and mass are the

meter (m) and kilogram (kg).

Temperature

• A measure of the hotness or coldness of an object.

• The Celsius (˚C) scale: the freezing point (0 ˚C) and

boiling point (100 ˚C) of water.

• The Kelvin (K) scale: The SI unit of temperature.

1.4 UNITS OF MEASUREMENTSI UNITS

• The Kelvin (K) scale- The temperature at which all thermal motion ceases in the

classical description of thermodynamics is defined as 0 K.

- The reference point that defines the Kelvin scale is the triple

point of water at 273.16K (0.01 ˚C).

Temperature

1.4 UNITS OF MEASUREMENTSI UNITS

Temperature

1.4 UNITS OF MEASUREMENTSI UNITS

Volume

1.4 UNITS OF MEASUREMENTDERIVED UNITS

Density is defined as

the amount of mass in

a unit volume of a

substance. ( g/cm or g/mL)

1.4 UNITS OF MEASUREMENTDERIVED UNITS

Exact numbers• 12 eggs in a dozen

• 1000 g in a kilogram

• 1 kg = 2.2046 lb

Inexact numbers• Numbers obtained by measurement

• Uncertainties always exist in measured quantities.

1.5 UNCERTAINTY IN MEASUREMENTEXACT NUMBERS AND INEXACT

NUMBERS

precision• a measure of how closely individual

measurements agree with one another.

• standard deviation, reproducibility

accuracy• a measure of how closely individual

measurements agree with the correct, or true

value

1.5 UNCERTAINTY IN MEASUREMENT

PRECISION AND ACCURACY

All digits of a measured quantity, including the

uncertain one, are called significant figures.

1.5 UNCERTAINTY IN MEASUREMENT

SIGNIFICANT FIGURES

FIGURE 1.24 uncertainty and significant figures in a measurement

1.5 UNCERTAINTY IN MEASUREMENT

SIGNIFICANT FIGURES

All nonzero digits are significant. Zeros between two significant figures are

themselves significant. (1005 kg, 1.03 cm) Zeros at the beginning of a number are never

significant. (0.02 g, 0.00025 cm) Zeros at the end of a number are significant if a

decimal point is written in the number. (0.0200 g, 3.0 cm)

10,300 g•1.03 × 104 g•1.030 × 104 g•1.0300 × 104 g

1.5 UNCERTAINTY IN MEASUREMENT

SIGNIFICANT FIGURES

1.5 UNCERTAINTY IN MEASUREMENT

SIGNIFICANT FIGURES

Addition and subtraction

Multiplication and division

In rounding off numbers•7.248 → 7.2•2.376 → 2.4•4.735 → 4.74

1.5 UNCERTAINTY IN MEASUREMENT

SIGNIFICANT FIGURES IN CALCULATIONS

1.5 UNCERTAINTY IN MEASUREMENT

SIGNIFICANT FIGURESSample Exercise 1.7 Determining the Number of Significant Figures

in a Calculated Quantity

The width, length, and height of a small box are 15.5 cm, 27.3 cm, and 5.4 cm, respectively. Calculate the volume of the box, using the correct number of significant figures in your answer.

It takes 10.5 s for a sprinter to run 100.00 m. Calculate her average speed in meters per second, and express the result to the correct number of significant figures.

Answer: 9.52 m/s (three significant figures)

Practice Exercise