Chapters 1 and 2

Matter and Change

Measurements and Calculations

Section 1-1

Chemistry is a Physical Science

What two categories were the natural sciences divided into? Physical Science: The study of nonliving

things.

Biological Science The study of living

things.

These two divisions are no longer used. Why not? In the early periods of

scientific discovery, there was a belief called “vitalism”.

Vitalism was the belief that living things contained some vital material that nonliving things did not.

Friederich Wohler – 1800 - 1888

This was first disproved by Friederich Wohler

Wohler synthesized the simple organic compound urea from inorganic substances.

This demonstrated that living things carry out chemical reactions that are similar to nonliving things, ending vitalism.

A Brief History of Chemistry

Ancient Greeks 1600’s – The Alchemists 1700’s – Antoine Lavoisier 1800’s – Modern Period of Chemistry

Ancient Greeks

First chemical theories developed by Aristotle.

These theories remained unchanged from this time until the 1600’s.

1600’s – The Alchemists

Attempted to discover the “philosopher’s stone”, which was a method to turn base metals into gold by a process called transmutation.

Their experiments failed, but they created many of the modern tools of chemistry.

Antoine Lavoisier : 1743-1794

First to describe and define a combustion reaction.

Proposed the Law of Conservation of Matter.

Developed binomial nomenclature for naming substances.

Placed emphasis on careful and accurate measurements.

Known as “the Father of Modern Chemistry”.

Laviosier’s contributions to chemistry ended in 1794 during the French Revolution, when Laviosier, a former tax collector fell victim to the “Reign of Terror.”

Late 1800’s to Present

It was not until the late 1800’s that the theories of Aristotle began to be abandoned, and true chemistry began to evolve.

Almost all of our current chemical knowledge has been gained in the past 200 years of human history, making chemistry a relatively new science.

What is Chemistry?

Chemistry is the study of the composition, structure, and properties of matter, and the changes it undergoes.

It is divided into many different branches of study and research.

The Six Branches of Chemistry

AnalyticalChemistry Biochemistry Inorganic

ChemistryOrganic

ChemistryPhysical Chemistry

Theoretical Chemistry

Analytical Chemistry

The identification of the composition of materials.

Biochemistry

The study of the chemistry of living things.

This branch developed from organic chemistry.

Inorganic Chemistry

The study of substances that do not contain carbon.

Organic Chemistry

The study of compounds that contain carbon.

This branch was started as the result of the experiments of Wohler.

Physical Chemistry

The study of relationships between matter and energy.

This branch was originally developed by Laviosier.

Theoretical Chemistry

The use of computers and mathematics to predict the properties of new compounds.

These branches tend to overlap each other, and a chemist may specialize in one but work in several at any given time.

Regardless of the branch of chemistry being studied, there are two terms every chemist must be familiar with.

Chemicals: A chemical is any substance with a definite composition.

Molecule: A molecule is the smallest unit of a chemical that has the properties of that chemical.

Types of Chemical Research

TheThree TypesOf Research

BasicResearch

Applied Research

TechnologicalDevelopment

Basic Research

Research that is carried out only for the sake of increasing knowledge.

Applied Research

Research carried out to solve a problem.

Technological Development

Production of goods or services that improve someone’s quality of life.

Section 1-2

Matter and its Properties

What is Matter?

Matter is any substance that has mass and volume.

Mass – a measurement of the amount of matter an object has.

Volume – the amount of space an object occupies.

All matter is made up of atoms. An atom is the smallest

unit of an element that maintains the properties of that element.

An element is a pure substance made of only one type of atom.

electron

neutron

proton

Another type of pure substance is a compound A compound is a

substance that is made of two or more elements which are chemically bonded.

All substances have characteristic properties There are two main types of properties. Extensive Properties – Properties that

depend on the amount of matter present. Intensive Properties – Properties that do not

depend on the amount of matter present.

Intensive Properties are further divided into two more categories. Physical Properties/Physical Changes – A

characteristic or a change that can be observed without changing the identity of the substance.

A change of state is a physical property. This is the change of a substance from one state of matter to another.

Chemical Properties/Chemical Changes – A characteristic or change that can only be observed by changing the identity of the substance.

Chemical Changes are also called chemical reactions.

There are three common states of matter

States of Matter

Solid Liquid Gas

Solid

Matter with definite shape and volume.

Particles are packed close together.

Particle motion is only slight vibrations.

Incompressible. Expand and contract

only a little.

Liquid

Matter with definite volume but no definite shape.

Particles are close, but can flow past each other.

Incompressible. Expand and Contract

only a little.

Gas

Matter with no definite shape or volume.

Little attraction between particles, and a lot of open space.

Very fast and free particle motion.

Compressible. Expand and Contract a

great deal.

Chemical Reaction

Described by a chemical formula. Starting materials are called Reactants. Ending materials are called Products. The following is a sample chemical formula: Hydrogen + Oxygen Water Chemical reactions almost always involve a

change in energy.

Law of Conservation of Energy In a chemical reaction

or physical change of state, energy is neither created, nor destroyed; only conserved.

Matter can be classified into two groups The first is pure substances, we have already

talked about these. These are substances whose composition is the same throughout and does not vary from sample to sample. These are elements and compounds.

The second type of matter is a mixture. This is a physical blend of two or more kinds of matter, each of which retains its own unique properties.

There are two types of mixtures The first is called homogenous. These are

mixtures that have a uniform composition. Homogenous mixtures are often called

solutions. An example of a homogenous mixture would

be salt water.

There are two types of mixtures The second type is a

heterogeneous mixture. These are mixtures that do not have a uniform composition.

An example of this would be a salad.

All mixtures can be separated by ordinary physical means. You do not need to do any chemical

reactions to separate a mixture. Each part of a mixture is called a phase. Homogenous mixtures have only one phase. Heterogeneous mixtures must have two or

more phases.

Section 1-3

Elements

Every element has individual properties They are organized into

groups based on similar properties on the periodic table.

Vertical columns are called families or groups, which contain elements with similar properties.

Horizontal rows are called periods, which separate elements with similar properties.

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There are two main divisions of elements on the periodic table Group A elements – These are known as the

representative elements, because each of the three known types of elements are found there. These are the tall columns of the periodic table.

Group B elements – These are known as transition metals, because only metals are found in this group. These are the shorter columns in the middle and at the bottom of the periodic table.

There are three main types of elements on the periodic table. Metals Nonmetals Metalloids

Metals

Shiny or lustrous Good conductors of

heat and electricity. Usually solids at room

temperature. Malleable – Can be

pounded into shapes. Ductile – Can be drawn

into wires. Found at left and center

of periodic table.

Nonmetals

Can be solids, liquids, or gases at room temperature.

Brittle. Poor Conductors of

heat and electricity. Found on the right side

of the periodic table, and includes hydrogen on the left.

Metalloids

Share properties of both metals and nonmetals.

All are solids at room temperature.

Brittle. Shiny or Lustrous. Semiconductors. Found touching stair

step line on a side.

Noble Gases

Group 8A elements. Very unreactive. All gases at room

temperature. Very stable. Also called inert gases. Light brightly when

electric current is passed through them.

Chapter 2

Measurement andCalculations

Section 2-1

The ScientificMethod

What is the Scientific Method? The scientific method is a logical approach to

solving problems. It does not just apply to scientific problems,

but any type of problem. There are five steps to the scientific method.

Step 1: Develop a Question

You must have a definite question in mind before you begin.

All work is done with the question in mind.

Step 2: Observe and Collect Data

Take measurements or collect data.

The best way to collect data is through experimentation.

An experiment is a procedure carried out under controlled conditions.

There are two types of data.

Two types of Data

Qualitative Descriptive Non – Numeric

Measurements.

Quantitative Numerical

Measurements.

Step 3: Formulate a Hypothesis Examine data for any

patterns that have formed.

A hypothesis is an educated guess based on the data collected.

Step 4: Test the Hypothesis

Further experimentation.

If the experiments do not support the hypothesis, it must be rejected and a new one formed.

If experiments do support the hypothesis, it is accepted but tested more.

Step 5: Form a Theory

A theory is a thoroughly tested hypothesis.

Theories are never proven. A proven statement is a law.

Theories are described by models.

What is a model?

A model is an explanation of how something occurs and how data is related.

A model can be visual, verbal, or mathematical.

Theory vs. Law

A Theory: Is an explanation of

how something occurs. It is never proven.

A Law: Is a description of a

natural event. It is a proven

statement. A theory will NEVER

become a Law.

Section 2-2

Unit of Measurement

A Brief History of Measurement For centuries, ancient

units of measurement have been used, in most cases using body parts.

Feet, hands, and cubits are all examples of this.

What problems occur from this?

They vary between people.

A Brief History of Measurement As different countries

began to exchange information, it became obvious that a standardized system of measurement was needed.

This was accomplished in 1960 with the SI system.

SI System

Le System International d’Unites Composed of Standards that have a constant

value. The SI system is based on seven base units. All other units are derived from combinations

of one or more base units.

Seven Base Units

Length – Meter (m) Mass – Kilogram (kg) Time – Second (s) Temperature – Kelvin (K) Amount of Substance – Mole (mol) Electric Current – Ampere (A) Light Intensity – Candela (cd)

Some terms are different between the SI and the metric system.

The SI system never uses commas in a number.

The two main base units we are concerned with for this chapter are length and mass.

Length

Base unit is the meter. A kilometer is 1000

meters. A centimeter is 1/100 of

a meter. A millimeter is 1/1000

of a meter.

Mass The SI unit for mass is the

kilogram. The gram is 1/1000 of a

kilogram. The centigram is 1/100 of a

gram. The milligram is 1/1000 of a

gram. There is a difference

between mass and weight. Mass is a measure of the

amount of matter. Weight is a measure of the

force of gravity.

There are seven main Derived Units of the SI System Area – meters squared (m2) Volume – meters cubed (m3) Density – kilograms per cubic meter (kg/m3) Molar Mass – kilograms per mole (kg/mol) Concentration – moles per cubic meter (mol/m3) Molar Volume – cubic meters per mole (m3/mol) Energy – Joules (J) We are only concerned with volume, density, and

concentration.

Volume

We usually use cubic meters or cubic centimeters to measure volume.

1 cubic meter = 1000 cubic centimeters 1 cubic meter = 1 Liter 1 cubic centimeter = 1 milliliter Volume = length * width * height

Density Mass divided by volume. Is density intensive or

extensive? It is intensive because as

mass goes up, so does volume, so density is unchanged.

Density does depend on temperature.

Changes in temperature cause changes in volume without changes in mass.

See chart on page 38.

Concentration

The amount of solute in a given amount of solvent or solution.

Solute is the substance being dissolved in a solution.

Solvent is the substance the solute is dissolved in.

There are several ways to measure concentration.

Concentration

Parts per million (ppm) or parts per billion (ppb) measure the number of atoms of solute per million or billion molecules of solute.

Molarity (M) – Moles of solute per liter of solution.

Molality (m) – Moles of solute per kg solvent.

Section 2-3

Using ScientificMeasurement

How Useful are Measurements? Two terms describe how

useful a measurement is.

Accuracy – closeness of a set of measurements to the true value.

Precision – closeness of a set of measurements to each other.

Errors

Errors are unavoidable in every experiment. There are three sources of error that cannot

be helped.

Human Error

Error in the type of measurement

Error in the Measuring Tool

Significant Figures

All of the known digits, plus one estimated digit.

It is a means of estimating to overcome the effect of accumulated errors.

There are five steps to doing significant figures.

Significant Figures

All nonzero number are significant. All zeros between two nonzeros are

significant. All zeros in front of a number are not

significant. Zeros at the end of a number without a

decimal point are not significant. Zeros at the end of a number with a decimal

point are significant.

Significant Figures requires Rounding There are five rules for rounding. If the number following the last number to be

kept is greater than five, round up. If the number following the last number to be

kept is less than five, round down. If the number following the last number to be

kept is five followed by other nonzero numbers, round up.

Significant Figures Requires Rounding If the number following the last number to be

kept is five followed by no nonzero numbers, and the last number to be kept is odd, round up.

If the number following the last number to be kept is five followed by no nonzero numbers, and the last number to be kept is even, round down.

Math and Significant Figures

To add or subtract, keep the same number of places after the decimal in your answer as there are in the number in the problem with the fewest places after the decimal.

To divide or multiply, keep the same number of significant figures in the answer as there were in the number in the problem with the fewest significant figures.

Scientific Notation

A way of writing numbers as M * 10n, where M is a number between 1 and 10, and n is any whole number.

The exponent n is determined by the number of places you must move the decimal.

For example, 150 000 would be written as 1.5 * 105.

Math in Scientific Notation

To add or subtract numbers in scientific notation, first get the exponents the same by moving the decimal in one of the numbers. Then add or subtract the numbers and leave the exponents alone.

To multiply, multiply the coefficients, and add the exponents.

To divide, divide the coefficients, and subtract the exponents.