Chapter 1 “Chemistry and You”

Or

“Why should I take Chemistry?”

“Why should I take Chemistry?”

• Here are some good reasons:– Impress your family and friends by using words like

“stoichiometry,” “colligative properties,” “anions,” “cations” and “redox.”

– “Chemistry” will look good on your transcript.– You will finally learn what goes into hotdogs.– Discover the difference between “moles,” “moles,”

and “moles.”– Find out how fireworks color the sky.– Learn how to calculate the volume of 637 grams of

steam at 2,000°C and 5 atmospheres of pressure.

QUESTIONS FOR THE FIRST DAY OF CHEMISTRY CLASS

• What is Chemistry?

• How does Chemistry impact us in our daily life?

• What human activities require Chemistry?

• Why is Chemistry considered the ‘central’ science?

• Is Chemistry hard?

• How can I get an “A” in this class?

Chapt. 1 Objectives

• Explain what chemistry is, and why it is important to many human activities.

• List and describe the steps of the Scientific Method.• Explain the basic safety rules to be followed when

working in the laboratory.• Identify the metric units of measurement.• Explain the causes of uncertainty in measurements.• Compare “precision” and “accuracy.”• Explain the use of significant figures and scientific

notation.• Calculate percent error, and determine density.• Explain how dimensional analysis and conversion factors

are used in solving problems in chemistry.

1-1 What is Chemistry?

• Chemistry is the study of substances and the changes they can undergo.

• Chemistry is the ‘central science’ because it overlaps and impacts so many other sciences.

• Do Now: Use these two concepts to show how chemistry is used by people you know.

Why study Chemistry?• It affects our lives in many ways.

– Food, medicine, biotechnology, fuels, transportation, electronics, plastics, the environment, clothing, etc. involve chemicals.

– Everything we wear, eat, drink and use is chemical.– In fact, we, too, are made up of chemicals (mostly water!).

• It helps us understand things around us.– Like rusting cars, cooking food, coloring our hair, floating

balloons, treating diseases, making electronics.– We will be able to arrive at informed opinions and take suitable

action on issues.

• It could lead to an interesting career.– Art historian, research scientist, environmentalist, materials

scientist, physician, technical writer, patent lawyer and hundreds of other occupations requiring some knowledge of chemistry.

• Besides, Chemistry is fun!

Is Chemistry Hard?

• NO!• It’s like learning a new language through which

we are able to understand the sub-microscopic world.

What skills will I develop by studying Chemistry?

• Technical reading skills (which differ from ‘casual’ reading skills).

• Good observation skills.• Organizational, analytical and interpretive

skills (the ‘thinking’ skills).• Good factual recall.• Mathematical manipulations, especially

from text problems and graphs.• Valuable laboratory skills.

Tips for Studying Chemistry(Getting that ‘A’!)

• Make an effort every day!• Read the topics more than once, & write notes to

summarize what you read.• Use the slides and outlines provided on-line.• Try to explain the concepts to someone else.• Use the text, including the drawings & photos.• Get organized, and stay that way.• Solve lots of practice problems, and complete all

of the worksheets and assignments.• Work alone or in groups.• Get help when you need it!

Chapt. 1 Objectives

• Explain what chemistry is, and why it is important to many human activities.

• List and describe the steps of the Scientific Method.• Explain the basic safety rules to be followed when

working in the laboratory.• Identify the metric units of measurement.• Explain the cause of uncertainty in measurements.• Compare precision and accuracy.• Explain the use of significant figures and scientific

notation.• Calculate percent error, and determine density.• Explain how dimensional analysis and conversion factors

are used in solving problems in chemistry.

1-2 The Scientific Method

• The Scientific Method is a way of answering questions about the world around us.

• It is an orderly and systematic approach to gather knowledge, develop ideas, check those ideas against observations, and to refine the ideas.

• Chemistry makes use of the cycle:

OBSERVE

HYPOTHESIZE (Represent)INTERPRET

Steps of the Scientific Method

• Make an observation.• Pose a question about the observation.• Propose a hypothesis to tentatively answer the

question.• Test the hypothesis with careful experiments.• Interpret the experiments and generate a conclusion.• Since the experiments may lead to new questions,

additional experiments may be needed and the conclusions may need to be revised.

• Pose a natural law, which describes how (but not why) nature behaves the way it does.

• Formulate a theory to explain why nature behaves in the way it does.

PREDICTION

THEORY

The Scientific Method: 1. OBSERVATION

2. QUESTION

3. HYPOTHESIS

4. EXPERIMENT

5. CONCLUSION

EXPERIMENT

NATURAL LAW

MODIFY THEORYAS NEEDED

Activities

• Since good observation skills are at the start of the Scientific Method, let’s test your skills.– View the next slide and record your

observations.– Pose a question about what you see.– Try to organize the information, and propose

a hypothesis to explain it.– Suggest an experiment to test the hypothesis.

Hypothesis & Experiment

• Practice Problems (pages 10, 11).

• Experiment– Variables: the factors being tested.– Controls: factors that respond in a predictable way.

• Many experiments lead to– Natural Laws (These summarize many observations,

but the Natural Law does not explain things.)– Theory (This provides the explanation, or a “super

hypothesis.”)– Is this the end of the story?

NO!

• Even long-accepted scientific theories may be revised (or even abandoned) as new scientific evidence emerges from carefully run experiments.– The “Flat Earth Society.”– The Earth as the center of the Universe!– Pluto as a planet.

• We will see how this works when we study the development of the Atomic Theory.

Objectives

• Explain what chemistry is, and why it is important to many human activities.

• List and describe the steps of the Scientific Method.• Explain the basic safety rules to be followed when

working in the laboratory.• Identify the metric units of measurement.• Explain the cause of uncertainty in measurements.• Compare precision and accuracy.• Explain the use of significant figures and scientific

notation.• Calculate percent error, and determine density.• Explain how dimensional analysis and conversion factors

are used in solving problems in chemistry.

1-3 Safety in the Laboratory

• Demonstrations– Prof. Ira Remsen’s experiment.– “The Egg and the Eye.”– Contact lenses.– Fire! Fire!– Scavenger hunt.– Safety symbols (page 15).– Safety Rules.– Safety Contract.

Did We Meet the Objectives?

• Explain what chemistry is, and why it is important to many human activities.

• List and describe the steps of the Scientific Method.• Explain the basic safety rules to be followed when

working in the laboratory.• Identify the metric units of measurement.• Explain the cause of uncertainty in measurements.• Compare precision and accuracy.• Explain the use of significant figures and scientific

notation.• Calculate percent error, and determine density.• Explain how dimensional analysis and conversion factors

are used in solving problems in chemistry.