CH1000 Fundament als of Chemistry Module 1 – Chapter 1

An Introduction into Chemistry

• What is Chemistry? • “Chemistry is the science of the composition, structure, properties, and reactions of

matter, especially of atomic and molecular systems.” • Simply put, chemistry is the study of matter and matter is any object that has mass and

occupies space. • The study of chemistry is vast and broad. From interactions between atoms which form

the building blocks of the universe to large energetic changes such as thermal transfer which makes life possible. Your life is touched by chemistry every day.

• Chemists try to understand the how and why chemical changes occur. • Chemists and other scientists use the scientific method as a means to gain

understanding and solve problems.

The Scientific Method

Observations Laws

Hypothesis

Experiment

Theory (model)

(analysis) (explanation)

(analysis)

1. Make an observation / Form a question 2. Collect facts or data that is relevant to your

observation/question. (Generally done through experimentation)

3. Formulate a hypothesis that accounts for the data on hand and can be tested by further experimentation.

4. Plan and do additional experiments to test the hypothesis.

5. Modify the hypothesis as necessary so that it is compatible with all pertinent data.

Hypothesis , Theory, Laws

A hypothesis is a tentative explanation of certain facts that provides a basis of further explanation.

• During experimentation, the hypothesis should be the expected outcome of the process based on all previous information.

Once a hypothesis has become well tested and established, it is called a theory, or a model.

• Scientific theory is well tested and generally established information. It is an explanation of the general principles of certain phenomena with considerable evidence or facts to support it.

• Scientific theory can be changed or disproven as new information becomes available and/or new discoveries are made.

Scientific laws are simple statements of natural phenomena to which no exceptions are known under the given conditions. • An example of a scientific law is Newton’s law of gravity. Gravity is a

natural phenomena which exists in the universe with no known exceptions.

Physical States of Matter – Solid, Liquid, Gas

•Solid • Definite shape and volume • Rigid particle structure • Shape can be independent of

container • Very slight compressibility

•Liquid • Definite volume but indefinite

shape • Firm but not rigid particle

structure (surface tension) • Takes shape of container • Slight compressibility

•Gas • Indefinite volume and no

fixed shape • Particles independent of each

other and far apart • Highly compressible

Classifying Matter •The term matter refers to all materials. •A substance is a type of matter with a definite, fixed composition. •A pure substance is either an element or compound. • Some common elements are copper, gold and iron • Some common compounds are salt, sugar and water

•Homogeneous matter is uniform in appearance and has the same properties throughout

•Heterogeneous matter consists of two or more physically distinct phases

•A phase is the homogeneous part of a system separated from other parts by a physical boundary

•A system is simply the body of matter under consideration

Mixtures

• A mixture is a material containing two or more substances and can be either heterogeneous or homogeneous.

Pure Substance Mixture

Always has a definite composition by mass.

Always contains two or more substances that can be present in varying amounts

The elements in a compound lost their identities and may be separated only by chemical means.

The components of a mixture do not lose their identities and may be separated by physical means

Matter

Pure Substance (homogeneous composition)

Mixtures of two or more

substances

Elements Compounds Solutions

(homogeneous composition – one

phase)

Heterogeneous mixtures (two or

more phases)

Reading Review

Provide an example of a homogeneous mixture.

Provide an example of a heterogeneous mixture.

List the physical states of matter.

True or False: A solution is another term for homogeneous mixture

Fill in the blank: Oxygen is a ____ _________ which exists in a mixture commonly known as air.

Slide 1
An Introduction into Chemistry
The Scientific Method
Hypothesis, Theory, Laws
Physical States of Matter – Solid, Liquid, Gas
Classifying Matter
Mixtures
Reading Review