Chapter 1- The Chemical World

Chapter 1- The Chemical World

Presenter

Dr. Luis Bello

[e-mail]

Texbook

Sixth Edition, Nivaldo J. Tro

ISBN 10: 0-134-30238-9;

ISBN 13: 978-0-134-30238-6 (Student edition)

The Chemical World

This chapter presents an understanding of the history of chemical investigation.

It is hoped that this will help the student understand the history of experimentation and scientific inquiry so that he or she feels a real-world association with the material to be covered later in the course.

Summary

• 1.2 Chemicals Compose Ordinary Things 

• 1.3 The Scientific Method: How Chemists Think 

• 1.4 Analyzing and Interpreting Data:  Identifying Patterns in Data, Interpreting Graphs 

Open Ended

Can you identify and list topics or concepts that are not related to or do not involve chemistry?

​Branches of Chemistry

Matter​

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Key Points

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• Matter exists in three main states: solid, liquid, or gas.

• In solids, particles are tightly packed, maintaining a fixed shape.

• Liquids have loosely packed particles, allowing them to take the shape of their container while retaining volume.

• Gases have particles so loosely packed that they lack a defined shape or volume and can be compressed.

Aggregation states

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Terms

• Solid: A substance that retains its shape and size without a container; its molecules are tightly packed and can only vibrate in place.

• Gas: A substance that fills and takes the shape of its container, with molecules that move freely and have negligible intermolecular interactions.

• Liquid: A substance that flows, taking the shape of its container while maintaining a constant volume; its molecules are loosely packed and in constant motion.

Properties of solids, liquids and gases

​key points

A pure substance is a material that consists of only one type of particle—either a single element or a single compound. It has a uniform composition and distinct chemical properties. For example, pure water (H₂O) and pure gold (Au) are pure substances because they contain only water molecules and gold atoms

Pure substance: One type of particle, with a uniform composition, cannot be separated into simpler substances by physical means.

On the other hand, a mixture is a combination of two or more substances that are physically combined, not chemically bonded. The components of a mixture retain their properties and can be separated by physical means. Mixtures can be either homogeneous (uniform composition, like salt water) or heterogeneous (non-uniform composition, like a salad).

Mixture: Multiple types of particles, variable composition, can be separated by physical means.

Multiple Choice

What is a mixture?

• elements chemically combined

• a combination of different substances

• composed of one atom only

• it is made of chemical

Multiple Choice

What type of mixture is this?

• heterogeneous 
• homogeneous

Multiple Choice

Sand floating in water, but most of the sand is settled at the bottom this an example of which type of mixture?

• A solution
• A colloid
• A suspension
• A compound

Ways to describe matter

To understand matter and how it changes, we need to be able to describe matter.

There are two basic ways to describe matter: physical properties and chemical properties. 

Physical properties are characteristics that describe matter as it exists. Some of many physical characteristics of matter are shape, color, size, and temperature.

​Key Points

• All properties of matter are either physical or chemical properties and physical properties are either intensive or extensive.

• Extensive properties, such as mass and volume, depend on the amount of matter being measured.

• Intensive properties, such as density and color, do not depend on the amount of the substance present.

• Physical properties can be measured without changing a substance’s chemical identity.

• Chemical properties can be measured only by changing a substance’s chemical identity.

Chemical properties

Chemical properties are characteristics of matter that describe how matter changes form in the presence of other matter.

Burning is a chemical property.

 Physical properties

 Physical properties are characteristics that describe matter as it exists.

Some of many physical characteristics of matter are shape, color, size, and temperature.

Multiple Choice

Blue Color: Chemical or Physical Property

• Chemical Property
• Physical Property

Multiple Choice

Density: Chemical or Physical Property

• Chemical Property
• Physical Property

Multiple Choice

Flammability (burns): Chemical or Physical Property

• Chemical Property
• Physical Property

Multiple Choice

Solubility (dissolves): Chemical or Physical Property

• Chemical Property
• Physical Property

Multiple Choice

Brittleness: Chemical or Physical Property

• Chemical Property
• Physical Property

Multiple Choice

Melting Point: Chemical or Physical Property

• Chemical Property
• Physical Property

Atomic theory

Atomic theory is the scientific theory that matter is composed of particles called atoms.

Atomic theory traces its origins to an ancient philosophical tradition known as atomism.

According to this idea, if one were to take a lump of matter and cut it into ever smaller pieces, one would eventually reach a point where the pieces could not be further cut into anything smaller. Ancient Greek philosophers called these hypothetical ultimate particles of matter atomos, a word which meant "uncut".

The Scientific Method: How Chemists think

• In the scientific method, observations lead to questions that require answers.

• In the scientific method, the hypothesis is a testable statement proposed to answer a question.

• In the scientific method, experiments (often with controls and variables) are devised to test hypotheses.

• In the scientific method, analysis of the results of an experiment will lead to the hypothesis being accepted or rejected.

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Key Points

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Terms

• scientific method a way of discovering knowledge based on making falsifiable predictions (hypotheses), testing them, and developing theories based on collected data

• hypothesisan educated guess that usually is found in an “if…then…” format

• control group a group that contains every feature of the experimental group except it is not given the manipulation that is hypothesized

Multiple Choice

A possible explanation to a problem that has not yet been tested. 

• data
• theory
• hypothesis
• fact

Multiple Choice

The factors in an experiment that can be changed. 

• variables
• quantitative data
• hypothesis
• steps

Multiple Choice

In a controlled experiment, how many variables can be worked with at a time? 

• one
• none
• two or more
• how ever many makes sense.

Multiple Choice

This part of the experiment shows the effect of the one variable being tested. 

• control group
• experimental group
• quantitative data
• hypothesis

Multiple Choice

This variable in an experiment is the one being deliberately changed by the scientist. 

• dependent variable
• independent variable
• data
• control group

Analyzing and interpretating data

Multiple Choice

How many total people took the survey?

• 50
• 150
• 100
• 200

Multiple Choice

Elliot says almost everyone arrived at the party after 10:00 P.M., but Nancy thinks most people came earlier. When did a majority of the people arrive? 

• 7:00-7:59 P.M.
• 8:00–8:59 P.M.
• 9:00–9:59 P.M.
• 10:00–10:59 P.M. 

Multiple Choice

How many cities have temperatures between 70 degrees and 99 degrees?

• 44
• 34
• 26
• 62

Multiple Choice

The study of carbon containing compounds.

• Organic Chemistry

• Inorganic Chemistry

• Physical Chemistry

• Biochemistry

Multiple Choice

The study of compounds that do not contain carbon.

• Organic Chemistry

• Inorganic Chemistry

• Biochemistry

• Analytical Chemistry

Multiple Choice

The study of the properties and changes in matter and their relation to energy.

• Physical Chemistry

• Biochemistry

• Organic Chemistry

• Inorganic Chemistry

Multiple Choice

The identification of the components and composition of materials refers to___________________________

• Biochemistry

• Physical Chemistry

• Organic Chemistry

• Analytical Chemistry

Multiple Choice

The study of substances and processes occurring in living things.

• Biochemistry

• organic Chemistry

• inorganic Chemistry

• Applied Chemistry

Multiple Choice

What is the definition of matter?

• Anything that has mass and takes up space

• A substance that is liquid, solid, or gas

• Anything that is pure

• Anything that you can see or hold

Multiple Choice

What is the first step in the scientific method?

• draw conclusions

• ask a question/make an observation

• make a hypothesis

• test the experiment

Multiple Choice

Should experiments be repeated over and over to see if the results are the same each time?

• yes
• no

Multiple Choice

All factors that can change in an experiment.

• variable
• data
• conclusion
• result

Multiple Choice

You will collect and record this during an experiment.

• data
• conclusion
• hypothesis
• background research

Multiple Choice

Any and every factor in an experiment that could be changed.

• control
• experimental
• variable
• conclusion

Multiple Choice

The factor changed by the experimenter during set-up.

• controlled
• independent
• experimental
• dependent

Multiple Choice

The factor observed/measured for change during the experiment.

• controlled

• independent

• experimental

• dependent