Chapter 1 - Introduction to Chemistry

Objectives

Define Chemistry Differentiate between the 5 branches of

Chemistry Apply the general plan in solving chemistry

word problems

SECTIONS

1.1 Chemistry 1.2 Chemistry Far and Wide 1.3 Thinking Like a Scientist 1.4 Problem Solving in Chemistry

1.1 Chemistry

Matter – anything that takes up space and has mass

Chemistry – the study of matter and the changes that matter undergoes

Organic Chemistry – the study of all chemicals that contain carbon

Inorganic Chemistry – the study of chemical that do not contain carbon

Biochemistry – the study of processes that take place in organisms

Analytical Chemistry – the study of composition of matter

Physical Chemistry – the area that deals with the mechanism, the rate and the energy transfer that occurs when matter undergoes a change

Pure Chemistry - the pursuit of chemical knowledge for its own sake

Applied Chemistry – research that is directed toward a practical goal or application

Technology – a system of tools, mechanisms, methods to solve a problem, improve a problem or change a problem

Vocabulary-Matter -Chemistry-Organic chemistry-Inorganic Chemistry-Biochemistry -Analytical Chemistry-Physical Chemistry-Pure Chemistry-Applied Chemistry-Technology

Video – What is Chemistry?

Branches of Chemistry

Inorganic Organic Analytical Physical Biochemistry

Identify some of the components of this picture and match it with one of the Chemistry branches

Mass vs Weight

Mass: a measure of the amount of matter that an object contains. (SI unit kilogram, kg)

Weight: The force with which the earth pulls on an object. (SI unit Newton, N)

Organic or Inorganic ?

Sulfuric Acid H2SO4

Methane CH4

Hydrochloric Acid HCl

Ethane C2H6

Science

What? Why?

How? When?

Science and Technology

Science Pure Does not necessarily have an application.

Technology Applied Has practical applications in society. Engineering.

1.2 Chemistry Far and Wide Macroscopic – objects are seen without a microscope

Microscopic - objects that cannot be seen without microscope

Biotechnology – an applied science that uses techniques to produce or process different things

Pollutant - a material found in air, soil or water that hurts living things

Vocabulary- Macroscopic- Microscopic- Biotechnology- Pollutant

Energy is the ability to do work.

Nature of Energy

Energy is involved when:

a bird flies. a bomb explodes. rain falls from the sky.

electricity flows in a wire.

Production of Energy

Hydroelectric plants use running water to generate electricity, however they may flood nearby lands and can disrupt the normal flow of water, both of which negatively affect the environment.

Wind power is increasingly being used as a clean source of renewable energy.

Turbines harvest wind on wind farms and generate electricity.

Solar power is a promising, renewable energy resource than can be turned into electricity, and it is used in many toys and even home heating.

Many other alternative energy sources like geothermal power, which draws upon the earth’s natural heat, and biomass, which produces an alternative to gasoline, are being considered in the movement away from fossil fuel dependence.

Conservation of Energy

In our everyday lives, we can also work to conserve energy.

Insulating, turning off lights and only using appliances like dishwashers when they are full are just some of the ways people can limit energy use in their homes.

Also, carpooling, bicycling, and taking public transportation are effective energy-saving ideas.

What is Biotechnology?

Biotechnology is the manipulation of living organisms and organic material to serve human needs.

Examples: Yeast in bread making and alcohol production Use of beneficial bacteria (penicillin) to kill harmful

organisms Cloning of plants and animals Artificial insemination

1750 B.C.

Origins of “biotechnology” emerge in methods of food production and plant and animal breeding Use of bacteria to produce cheese (food preservation)

Use of natural enzymes in yogurt Use of yeast to produce bread Use of fermentation for producing wine and beer

Biotechnology Industry

Focuses on a variety of research areas including: Health/medicine Food science Environmental science Agriscience

1.3 Thinking Like a Scientist

Scientific Method - a logical approach to the solution of a scientific problem

Observation – the use of senses to obtain an information

Hypothesis – an educated guess

Experiment – a procedure used to verify the hypothesis

Manipulated variable – the variable that you change during an experiment

Responding variable – the variable that is observed during the experiment

Theory - a well tested explanation for a broad set of observations

Scientific Law – a concise statement that summarizes the results of many observations and experiments

Vocabulary-Scientific Method-Observation-Hypothesis-Experiment-Manipulated variable-Responding variable-Theory-Scientific law

Steps of the Scientific Method

1. Problem/QuestionProblem/Question: Develop a question or problem that can be

solved through experimentation.

Steps of the Scientific Method

3. Formulate a HypothesisFormulate a Hypothesis: Predict a possible answer

to the problem or question.Example: If soil

temperatures rise, then plant growth will increase.

Steps of the Scientific Method

4. ExperimentExperiment: Develop and follow a procedure.Include a detailed

materials list.The outcome must be

measurable (quantifiable).

Steps of the Scientific Method

5. Collect and Analyze Collect and Analyze ResultsResults: Modify the procedure if needed.

Confirm the results by retesting.

Include tables, graphs, and photographs.

Steps of the Scientific Method

6. ConclusionConclusion: Include a statement that accepts

or rejects the hypothesis.

Make recommendations for further study and

possible improvements to the procedure.

Steps of the Scientific Method

7. Communicate the Communicate the ResultsResults: Be prepared

to present the project to an audience.

Expect questions from the audience.

Problem/Question

John wonders if the amount of sugar used in the recipe will affect the size of the bread

loaf?

Caution!Be careful how you use

effect and affect.Effect is usually a noun and

affect, a verb.“ The effect of sugar amounts on the rising of

bread.”“How does sugar affect the

rising of bread?”

Observation/Research

John researches the areas of baking and fermentation and tries to come up with a way

to test his question.

He keeps all of his information on this topic in a journal.

John talks with his teacher and she gives him an Experimental Design

Diagram to help him set up his investigation.

Formulate a Hypothesis

After talking with his teacher and

conducting further research, he comes

up with a hypothesis.

“If more sugar is added, then the bread will rise

higher.”

Hypothesis The hypothesis is an

educated guess about the relationship between the independent and dependent

variables.Note: These variables will be defined in the next few

slides.

Independent Variable

The independent, or

manipulated variable, is a factor that’s intentionally varied by the experimenter.John is going to use 25g., 50g., 100g., 250g., 500g. of

sugar in his experiment.

Dependent Variable

The dependent, or responding variable, is the factor that may change as a result of

changes made in the independent variable.

In this case, it would be the size of the loaf of bread.

Experiment

His teacher helps him come up with a procedure and list

of needed materials.

She discusses with John how to determine the control

group.

Control Group

In a scientific experiment, the control is the group that

serves as the standard of comparison.

The control group may be a “no treatment" or an

“experimenter selected” group.

Control Group

The control group is exposed to the same conditions as the experimental group, except for the variable

being tested.All experiments should have

a control group.

Control Group

Because his grandmother always used 50g. of sugar in her recipe, John is going to use that amount in his

control group.

Constants

John’s teacher reminds him to keep all other factors the same so that any observed changes in the bread can be

attributed to the variation in the amount of sugar.

Constants

The constants in

an experiment are all the

factors that the experimenter

attempts to keep the same.

Constants

They might include:Other ingredients to the bread

recipe, oven used, rise time, brand of ingredients, cooking

time, type of pan used, air temperature and humidity where

the bread was rising, oven temperature, age of the yeast…

Experiment

John writes out his procedure for his experiment along with a materials

list in his journal. He has both of these

checked by his teacher where she checks for any

safety concerns.

Trials

Trials refer to replicate groups

that are exposed to the same conditions in an experiment.

John is going to test each sugar variable

3 times.

Collect and Analyze Results

John comes up with a table he can use

to record his data.

John gets all his materials together and carries out his experiment.

Size of Baked Bread (LxWxH) cm3

Amt. of Sugar (g.)

1 2 3 AverageAverage

Size (cmSize (cm33))

25 768 744 761 758

50 1296 1188 1296 1260

100 1188 1080 1080 1116

250 672 576 588 612

500 432 504 360 432

Size of Bread Loaf Size of Bread Loaf (cm(cm33))

TrialsTrials

Control group

Collect and Analyze Results

John examines his data and notices that his control worked the best in this experiment, but not significantly

better than 100g. of sugar.

Conclusion

John rejects his hypothesis, but decides to re-

test using sugar amounts between 50g. and 100g.

Experiment

Once again, John gathers his materials and carries out his experiment.

Here are the results.

Can you tell Can you tell which which group did group did the best?the best?

Size of Baked Bread (LxWxH) cm3

Amt. of Sugar (g.)

1 2 3 AverageAverage

Size (cmSize (cm33))

50 1296 1440 1296 1344

60 1404 1296 1440 1380

70 1638 1638 1560 1612

80 1404 1296 1296 1332

90 1080 1200 972 1084

Size of Bread Loaf Size of Bread Loaf (cm(cm33))

TrialsTrials

Control group

Conclusion

John finds that 70g. of sugar produces the largest loaf.His hypothesis is accepted.

Communicate the Results

John tells his grandmother about his findings and

prepares to present his project in

Science class.

Producing aspirin tablets so that consumers can use them.

Question: Science or Technology?

Alchemists (~300BC-1650 AD)China, India, Arabia, Europe, Egypt

•Aiming to:

Change common metals to gold.Develop medicines.

•Developed lab equipment.

•Mystical.

Question:

Does an iron nail gain mass or lose mass when it rusts (a form of burning)?

Theory

A well tested explanation for a broad set of observations.

May use models. May allow predictions. Theories may change to explain new observations.

Law

A statement that summarizes results of observations, but does not explain them.

Changes or is abandoned when contradicted by new experiments.

Note:

The order of the steps can vary and additional steps may be added.

“No number of experiments can prove me right;

a single experiment can prove me wrong.”

Albert Einstein

Why Study Chemistry - 3 Main Reasons

1.) Understand the Natural World

2.) Career Preparation

3.) Becoming an informed citizen

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Why Study Chemistry?

Explaining the Natural World

why cut apples turn brown upon exposure to air.

why the texture of eggs changes from runny to firm as eggs are boiled.

why water expands as it freezes.

why sugar dissolves faster in hot water than in cold water.

why yeast makes bread dough rise.

Satisfy your curiosity…

Why Study Chemistry? Preparing for a

Career•Doctor•Nursing•Firefighter•Turf Management•Geothermal Specialist•Engineering•Artist•Chef•Mechanic•Painters•Farmer•Law Enforcement•Professional Hunter•Physical Therapist

Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

You do not need to have the word chemist in your job title to benefit from understanding chemistry.

Assignments Watch the PPT at least 2 times or read the textbook; - Understand and memorize the definitions of all key

terms; Write in your notebook (homework section) the key terms

and their definitions and some notes that you consider will help with the “do now” and they will meet the objectives

Solve for yourself all the questions and problems given by the textbook at the end of each section.

Assignments Watch the PPT at least 2 times or read the textbook; Understand and memorize the definitions of all key terms; Write in your notebook (homework section) the key terms

and their definitions and some notes that you consider will help with the “do now” and they will meet the objectives

Solve for yourself all the questions and problems given by the textbook at the end of each section.

Assignments

Homework check list: Date written on upper right corner; Title containing homework number, chapter

number and the name of the chapter.