(General Chem 1) Lecture 3. Classification of Matter

Matter is any physical material of the universe; it is anything that occupies space and has mass and volume.

CLASSIFICATION OF MATTER

            There are two principal ways of classifying matter; one is through its physical state, and the other is according to its composition.

            A. Based on its Physical/Mechanical State

1.    Solid- has both definite shape and definite volume. It cannot be compressed to any appreciable extent.

2.    Liquid- has a definite volume independent of its container but has no specific shape. It assumes the shape of the portion of the container it occupies.

3.    Gas- has no fixed volume and shape; rather it conforms to the volume and shape of its container. It can be compressed to occupy smaller volumes or expand to occupy larger volumes.

4.    Plasma- semi liquid or gaseous state that contains charged particles(ions).

5.    Bose-Einstein Condensate

            B. Based on the Chemical State/Composition

1. Pure Substances- are kind of matter that have distinct properties and composition that do not vary from sample to sample.

      a. Elements- are the simplest substances which cannot be decomposed or changed by physical or chemical means.

      b. Compounds- are substances composed of two or more elements and can be decomposed to simpler substances.

2. Mixtures- are combinations of two or more substances in which each substance retains its own chemical identity and can be separated through physical or mechanical means.

      a. Homogeneous Mixtures- mixtures that are uniform in size, shape and phase

                                                  components throughout.

Solutions- are kind of homogenous mixtures that have uniform composition and have very small size particle components.

      b. Heterogeneous Mixtures- mixtures that have different size, shape and phase

                                                    composition.

Colloids- mixtures containing particles larger than normal solutes(in solution) but small enough to remain suspended in a dispersing medium.

Suspensions- mixtures containing larger, visible particles.

(General Chem 1) Lecture 2. Chemistry as Science

            Chemistry is an experimental science. The idea of using experiments to understand nature seems like a natural pattern of thought. Thus, scientists have devised an approach in order to solve and explain different phenomena in the field of science.

Scientific Method is a logical approach to the solutions of problems, a dynamic or systematic process used to answer questions about the physical world.

STEPS IN SCIENTIFIC METHOD

1.    Identification of the Problem

2.    Collection of a Data/Information

3.    Formulation of Hypothesis

4.    Testing the Hypothesis/Experimentation

5.    Generalization/Formulation of Theories

FOUR DISTINCT PHASES OF SCIENTIFIC METHOD

a.    Observing- This is done once the problem has been identified. The scientist accumulates as much reliable data as possible about a phenomenon. There are mainly two types of observation;

                      i.    Quantitative- refers to the amount of matter or measurements.

                     ii.    Qualitative- refers to the nature or quality of matter.

b.    Generalizing- After observing, the scientist looks for patterns, trends or relationships among the data gathered.

c.    Theorizing- Here, the scientist attempts to develop a plausible explanation and construct a simple physical or mental model that relates the observed behavior to familiar and well understood phenomena.

d.    Testing- Once a simple theory is developed, it is tested and retested to establish the validity. The scientist continually tests observational and experimental data and predictions by subjecting them to new experiments.

IMPORTANT TERMINOLOGIES TO KNOW

§  Hypothesis- any tentative or arbitrary guess or explanation to a certain phenomenon. It is a suggested explanation for an observed set of facts or correlation in data.

–        Must be consistent with all known facts.

–        Must make predictions about results of new experiments.

•          If the predictions are inconsistent with the results of experiments, then the hypothesis is “falsified”

•          If predictions are consistent with results of experiments, hypothesis has been “supported” or “confirmed but not “proved”.

§  Theory- is a plausible explanation of an observed phenomenon and principle in terms of a model with common properties or with considerable evidence or facts to support it.

o   A hypothesis graduates to a theory when it has survived a great deal of experiment testing.

o   Well-supported enough by results that it is beyond “reasonable doubt” as an explanation.

o   Could be falsified by subsequent experiments.

§  Experiment- a sequence of observations carried out under controlled conditions

§  Scientific Law- is a concise verbal statement or mathematical equation that summarizes a broad variety of observations and experiences, that describes behavior of matter.

Note: Theories are never be proven to be absolutely correct. It may be discarded or modified as a result of developments or new experimentations. Scientific laws are considered general truths.

(General Chem 1) Lecture 1. The Field of Chemistry

This site will introduce first a basic course in Chemistry.

It consists of fundamental concepts such as stoichiometry, bonding and reactions.

Lecture 1. The Field of Chemistry

Chemistry is a physical science that deals with matter, its composition, structure, properties and the changes/processes it undergoes.

“Chemistry provides important understanding of our world and how it works. It is an extremely practical as well as intellectual science that greatly impacts our daily living. It lies near the heart of many matters; improvement of healthcare, conservation and protection of the environment and provision of our everyday needs for food, clothing and shelter. Chemistry, by its nature, is a CENTRAL SCIENCE. By studying chemistry, the powerful language and ideas that have evolved to describe and enhance our understanding of matter will be learned. The language of chemistry is a universal scientific language that is widely used in other disciplines.”

BRANCHES OF CHEMISTRY

ü  Analytical Chemistry is concerned with the separation, identification and composition of matter, quantitatively or qualitatively.

ü  Organic Chemistry is the chemistry of carbon compounds.

ü  Inorganic Chemistry deals with non-carbon related compounds.

ü  Physical Chemistry involves the study of physical characteristics of matter and the mechanism of the processes and reactions.

ü  Biological Chemistry is the chemistry of living organisms.

ü  Nuclear/Quantum Chemistry involves the study of sub-atomic and atomic particles and their reactions.

Chemistry is Easy

A lot of people are saying that CHEMISTRY is a difficult subject.
Sorry, but I beg to disagree.
Honestly, it's also like other subjects which can be taught and learned easily.
I know where do these people (i.e. students) are getting their thoughts about the field.
Anyway, this site will prove you wrong.
Chemistry will be shared and discussed far more different than it is in the classroom.
Moreover, I'll be sharing some techniques in problem solving and memorizing concepts.
I just hope that you'll be able to conquer your fears with numbers and chemical equations after your encounter here.
Let's get it on for the easy learning in Chemistry.