Introduction to Chemistry. Study of the _________________ of matter and the _________________ matter undergoes.

Introduction to Chemistry

Study of the _________________ of matter and the _________________ matter undergoes.

1. Organic chemistry - 2. Inorganic chemistry - 3. Analytical chemistry - 4. Physical chemistry 5. Biochemistry -

Understanding Concepts Chemistry deals with scientific

facts - facts that can be discovered by making observations and doing experiments.

It is often necessary to rely on information that others have discovered.

Diamond Hardest known substance. A form of the element carbon. Highly ordered molecular

structure. Not the most stable form of

carbon.

Macro vs. Micro _________________ - things you

see with the unaided eye or large scale experimenting.

_________________ - things too small to see with the unaided eye - or small scale experimenting.

Matter and Change

Matter Anything that has

_________________ and takes up _________________.

Everything is made up of matter.

Definitions for Components of Matter

_________________ - the simplest type of substance with unique

physical and chemical properties. An element consists of only

one type of atom. It cannot be broken down into any simpler

substances by physical or chemical means.

_________________ - a structure that consists

of two or more atoms that are chemically

bound together and thus behaves as an

independent unit.

_________________ - a substance

composed of two or more elements

which are chemically combined.

_________________ - a group of two or more elements and/or compounds that are physically intermingled.

Definitions for Components of Matter

_________________ - amount of matter the object contains - measured in grams.

_________________ - matter that has uniform and definite composition (pure substances) - contain only one kind of matter.

Physical Properties Quality or condition of a substance

that can be observed or measured without changing the substance’s composition.

Color odor hardness density melting & boiling points solubility

Physical properties help chemists _________________ substances.

Physical Change Matter can be changed in many

ways without changing the chemical composition of the material.

Cutting • Dissolving • Crack Grinding • Melting • Break

Boiling • Crush Bending • Freezing Tearing • Condensing

Melting or Freezing of Water

Melting ice into liquid is a physical change, along with changing liquid to steam and steam to condensation.

There is no alteration to the chemical composition of water, only a change of state.

Chemical Property The ability of a substance to

undergo a chemical reaction and to form new substances.

Chemical properties are only observed when a substance undergoes a chemical change.

A chemical change always results in a change in the chemical composition of the substances involved.

Burning Decompose Rust Explode Corrode Rot

Chemical Properties those which the substance shows as it interacts with, or transforms into, other substances such as flammability, corrosiveness

Physical Properties those which the substance shows by itself without interacting with another substance such as color, melting point, boiling point, density

Figure 1.1

A Physical change B Chemical change

The distinction between physical and chemical change.

Sample Problem 1.1 Distinguishing Between Physical and Chemical Change

PROBLEM: Decide whether each of the following process is primarily a physical or a chemical change, and explain briefly:

(a) Frost forms as the temperature drops on a humid winter night.

(b) A cornstalk grows from a seed that is watered and fertilized.

(c) Dynamite explodes to form a mixture of gases.

(d) Perspiration evaporates when you relax after jogging.

(e) A silver fork tarnishes slowly in air.

States of Matter

States of Matter

_________________ - definite shape and volume. Particles are packed tightly

together. Almost incompressible. Expand only slightly when

heated.

_________________ - indefinite shape and definite volume. In close contact with one another. Liquids can flow. Almost incompressible. Tend to expand when heated.

Gas - indefinite shape and volume. Gas particles are far apart. Easily compressed. Expand without limit to fill any

space. _________________ - describes the

gaseous state of a substance that is generally a liquid or solid at room temperature (different than a gas).

Classifying Mixtures

Physical blend of two or more substances.

Compositions may vary.

Heterogeneous Mixture

Not uniform in composition. If you were to separate the mixture

into portions, each portion would be different from the other.

Homogeneous Mixture

Completely uniform throughout. Components are evenly distributed

throughout. Separate the mixture into portions

and the portions would be the same.

Also called _________________ - may be gases, liquids, or solids.

Scientific Method An important scientific discovery may

involve some luck, but one must be prepared to recognize the lucky event. Alexander Fleming

Most advances in science involves little or no luck, but a logical systematic approach to the solution of a difficult problem.

Scientific Method

Logical approach to the solution of scientific problem.

Related to ordinary common sense.

ObservationUsing your senses to obtain information directly.

Hypothesis A possible _________________ or

_________________ for what is observed.

A proposal

Experiment Test the hypothesis. For the results of an

experiment to be accepted, the experiment must produce the same result no matter how many times it is repeated, or by whom.

If the experimenting does not support the hypothesis, the hypothesis must be changed.

The process of testing the hypothesis must be carried out until the hypothesis fits all the observed experimental facts.

Theory Once a scientific hypothesis

meets the test of repeated experimentation, it may become a theory.

A theory is a broad and extensively tested explanation of why experiments give certain results.

A theory can never be proved because it is always possible that a new experiment will disprove it.

Theories give you the power to predict the behavior of natural systems.

Scientific Law Concise statement that

summarizes the results of many observations and experiments.

Describes a natural phenomenon without attempting to explain it.

Can be expressed as a mathematical equation.

A _________________ states what happens; a _________________ explains why.

International System of Units

The Metric System

Metric System

The metric system was developed in France in the 1790s.

The metric system missed being nationalized in this country by one vote in the late 1700s.

Metric System

Based on the powers of 10.

Countries that have not officially adopted the Metric System include:

United States Liberia, Africa Berma, Southeast Asia

Why should we use the metric system?

We are living in a metric world where just about every country, except the USA, uses the metric system, and other countries are now telling us that they don't want to buy some of the products manufactured by U.S. companies if they aren't made to metric sizes (and if they aren't labeled in metric units).

Many European Union (EU) countries, which have been good customers of U.S. companies, don't allow products into their countries unless they are made to metric system standards. We must operate in the world marketplace, and we can't stay competitive if we don't provide metric goods.

In addition, beginning on January 1, 2010, the EU will require products to be labeled solely in metric measurements. If US laws are changed to allow metric-only labeling, it will be easier for US companies to comply with that directive.

With 99% of the rest of the world using metric, there is no chance we can persuade them to use our inches and pounds.

Metric System Based on the powers of 10

milli- centi- deci- (basic unit) deca- hecta kilo-

Between each step, there is an increase by a power of 10.

10 mm = 1 cm 10 cm = 1 dm 10 dm = 1 m 10 m = 1 dam 10 Dm = 1 hm 10 Hm = 1 km

Yotta Y 1024

Zetta Z 1021

Exa E 1018

Peta P 1015

Tera T 1012

Giga G 109

Mega M 106

Kilo k 103

Basic Unit 1 Milli m 10-3

Micro 10-6

Nano n 10-9

Pico p 10-12

Femtof 10-15

Atto a 10-18

Zepto z 10-21

Yocto y 10-24

As you move from a small to large, you move the decimal that many places to the left.

As you move from large to small, you move the decimal that many places to the right.

Units of Length

SI unit = meter (m) 1 meter = 1000 mm 1 meter = 1.09 yards = 39.36

inches 1 km = 1000 meters 1 km = 0.62 miles 1 inch = 2.54 cm

Units of Length

Unit used for measuring atoms in chemistry is the Ångström – Å = 10-8 cm

Centimeter is about the diameter of a dime

Millimeter is about the thickness of a dime

Units of Volume

_________________ occupied by any sample of matter.

SI unit = m3

More common unit = liter (L) 1 L = 1000 mL 1 mL = 1 cm3

Units of Volume

Unit of volume for a solid

length x width x height = volume of a regular shaped object (cm3)

1 mL = 1 cm3

One liter is a little more than a quart One cup is 250 mL

Units of Mass _________________ - measure of the

quantity of matter in an object. _________________ - force that measures

the pull of gravity on any given mass. SI unit = kilogram (kg) 1 kg = 1000 grams (g) 1 kg = 2.12 pounds One gram is about the mass of a paperclip

Units of Temperature

Kelvin Scale 0 K = -273C Degree Celsius (°C) 0°C = 32°F (freezing point of

water) 100°C = 212°F (boiling point of

water)

Conversion between Temperatures

F to C (C x 1.8) + 32 = F

C to F (F – 32) 1.8 = C

Time

SI Unit = second (s)

Graphing

Graphing

The relationship between two variables in an experiment is often determined by graphing the experimental data.

The graph is a “picture” of the data.

Graphing Information

_________________ Variable manipulated variable X-axis (horizontal)

_________________ Variable responding variable Y-axis (vertical)

Time (seconds)

Distance (meters)

0 0

5 3.5

10 6.2

15 10.1

20 17.3

25 26.5

30 37.1

Time vs. Distance

03.5

6.210.1

17.3

26.5

37.1

0

5

10

15

20

25

30

35

40

0 10 20 30 40

Time (seconds)

Dis

tan

ce (

mete

rs)

Scientific Measurement

Types of Measurements _________________ measurements -

results are given in descriptive, non-numerical form.

_________________ measurements - results are given in definite form, usually as numbers and units.

Scientific Notation A number written as the product of

two numbers: a coefficient and 10 raised to a power.

3.6 x 105

The coefficient is always written as a number greater than one and smaller than ten - only one number to the left of the decimal.

Multiplication & Division

In multiplication of scientific notation values, multiply the coefficients and add the exponents.

In division of scientific notation values, divide the coefficients and subtract the exponents.

Addition & Subtraction

Before adding or subtracting, the exponents must be the same.

After the exponents are the same, add or subtract the coefficients with the 10 raised to the power of.

Significant Figures

It is important to be honest when reporting a measurement, so that it does not appear to be more accurate than the equipment used to make the measurement allows. We can achieve this by controlling the number of digits, or _________________, used to report the measurement.

Rule 1:

All nonzero digits are significant.

Rule 2:

Zeros within a number are always significant. Both 4308 and 40.05 contain four significant figures.

Rule 3:

Zeros that do nothing but set the decimal point are not significant. Thus, 470,000 has two significant figures.

Rule 4:

Trailing zeros that aren't needed to hold the decimal point are significant. For example, 4.00 has three significant figures.

How many sig figs?

(b) 0.1044 g

(a) 0.0030 L

(c) 53,069 mL

(e) 57,600. s

(d) 0.00004715 m

(f) 0.0000007160 cm3

Rules for Sig Figs in Answers When combining measurements with

different degrees of accuracy and precision, the accuracy of the final answer can be no greater than the least accurate measurement.

This principle can be translated into a simple rule for addition and subtraction: When measurements are added or

subtracted, the answer can contain no more decimal places than the least accurate measurement.

Addition & Subtraction

106.78 mL = 106.8 mL

Example: subtracting two volumes

863.0879 mL = 863.1 mL

865.9 mL - 2.8121 mL

Example: adding two volumes 83.5 mL

+ 23.28 mL

Rules for Sig Figs in Answers The same principle governs the use of

significant figures in multiplication and division: the final result can be no more accurate than the least accurate measurement.

In this case, however, we count the significant figures in each measurement, not the number of decimal places: When measurements are multiplied or

divided, the answer can contain no more significant figures than the least accurate measurement.

Multiplication & Division

= 23.4225 cm3 = 23 cm39.2 cm x 6.8 cm x 0.3744 cm

Rounding

When the answer to a calculation contains too many significant figures, it must be rounded off.

Rounding

If the digit is smaller than 5, drop this digit and leave the remaining number unchanged. Thus, 1.684 becomes 1.68.

If the digit is 5 or larger, drop this digit and add 1 to the preceding digit. Thus, 1.247 becomes 1.25.

Uncertainty in Measurements

_________________ - measure of how close a measurement comes to the actual or true value of whatever is measured.

_________________ - measure of how close a series of measurements are to one another. (depends on multiple measurements)

precise and accurate

precise but not accurate