Chapter 1 “Introduction to Chemistry”

What is Chemistry?  Chemistry is the study of the composition of “matter” – (matter is anything with mass and occupies space), its composition, properties, and the changes it undergoes.  Has a definite affect on everyday life - taste of foods, grades of gasoline, etc.  Living and nonliving things are made of matter.

Chemistry is the study of the composition, structure, and properties of matter and the changes it undergoes – such as burning fuels. C 2 H 5 OH + 3 O 2  2 CO H 2 O + Energy Reactants  Products

5 Major Areas of Chemistry 1) Analytical Chemistry- concerned with the composition of substances. 2) Inorganic Chemistry- primarily deals with substances without carbon 3) Organic Chemistry- essentially all substances containing carbon 4) Biochemistry- Chemistry of living things 5) Physical Chemistry- describes the behavior of chemicals (ex. stretching); involves lots of math! Boundaries not firm – they overlap and interact

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What is Chemistry?  Pure chemistry- gathers knowledge for the sake of knowledge  Applied Chemistry- is using chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing – leads to an application* Nylon – Figure 1.3, page 9 * Aspirin (C 9 H 8 O 4 ) - to relieve pain * Use of TECHNOLOGY (benefit!)

Why Study Chemistry?  Everyone and everything around us involves chemistry – explains our world  What in the world isn’t Chemistry?  Helps you make choices; helps make you a better informed citizen  A possible career for your future  Used to attain a specific goal  What did we describe as “pure” and “applied” chemistry?

Why Study Chemistry?  Figure 1.2, page 8 –What benefits do each of the pictures represent in improving our lives? –Give examples in your daily life that involve use of chemistry, and things that do not?

Chemistry Far and Wide  Chemists design materials to fit specific needs – velcro (Patented in 1955) on page 12  perfume, steel, ceramics, plastics, rubber, paints, nonstick cooking utensils, polyester fibers  Two different ways to look at the world: macroscopic and microscopic

Chemistry Far and Wide  Energy – we constantly have greater demands –We can conserve it; use wisely –We can try to produce more; oil from soybeans to make biodiesel –fossil fuels, solar, batteries (that store energy – rechargeable?), nuclear (don’t forget pollution!)

Chemistry Far and Wide  Medicine and Biotechnology- –Supply materials doctors use to treat patients –vitamin C, penicillin, aspirin (C 9 H 8 O 4 ) –materials for artery transplants and hipbones –bacteria producing insulin

Chemistry Far and Wide  Agriculture –Produce the world’s food supply –Use chemistry for better productivity – soil, water, weeds –plant growth hormones –ways to protect crops; insecticides –disease resistant plants

Chemistry Far and Wide  The Environment –both risks and benefits involved in discoveries –Pollutants need to be 1) identified and 2) prevented –Lead paint was prohibited in 1978; Leaded gasoline? Drinking water? –carbon dioxide, ozone, global warming

- Page % 440,000 After lead was banned in gasoline and public water supply systems, less lead entered the environment. Let’s examine some information from a graph.

Chemistry Far and Wide  The Universe –Need to gather data from afar, and analyze matter brought back to Earth –composition of the planets –analyze moon rocks –planet atmospheres –life on other planets? Section 1.3 Thinking Like a Scientist

Alchemy – developed the tools and techniques for working with chemicals  The word chemistry comes from alchemy – practiced in China and India since 400 B.C.  Alchemy has two sides: –Practical: techniques for working with metals, glass, dyes, etc. –Mystical: concepts like perfection – gold was a perfect metal

An Experimental Approach  In the 1500s, a shift started from alchemy to science – King Charles II was a supporter of the sciences  “Royal Society of London for the Promotion of Natural Knowledge”  Encouraged scientists to use more experimental evidence, and not philosophical debates

Lavoisier  In the late 1700s, Antoine Lavoisier helped transform chemistry from a science of observation to the science of measurement – still used today  He settled a long-standing debate about burning, which was… –Oxygen was required!

The Scientific Method  A logical approach to solving problems or answering questions.  Starts with observation- noting and recording information and facts  hypothesis- a proposed explanation for the observation; must be tested by an experiment

Steps in the Scientific Method 1. Observations (uses your senses) a) quantitative involves numbers = 95 o F b) qualitative is word description = hot 2. Formulating hypotheses (ideas) - possible explanation for the observation, or “educated” guess 3. Performing experiments (the test) - gathers new information to help decide whether the hypothesis is valid

Scientific Method  “controlled” experiment- designed to test the hypothesis  only two possible answers: 1)hypothesis is right 2)hypothesis is wrong  We gather data and observations by doing the experiment  Modify hypothesis - repeat the cycle

Scientific Method  We deal with variables, or factors that can change. Two types: 1) Manipulated variable (or independent variable) is the one that we change 2) Responding variable (or dependent variable) is the one observed during the experiment  For results to be accepted, the experiment needs to always produce the same result

Outcomes over the long term…  Theory (Model) - A set of well-tested hypotheses that give an overall explanation of some natural phenomenon – not able to be proved  Natural Law (or Scientific Law) - The same observation applies to many different systems; summarizes results - an example would be: the Law of Conservation of Mass

Law vs. Theory A law summarizes what has happened. A theory (model) is an attempt to explain why it happened – this changes as new information is gathered.

- Page 22 Using your senses to obtain information Hypothesis is a proposed explanation; should be based on previous knowledge; an “educated” guess The procedure that is used to test the hypothesis A well-tested explanation for the observations; cannot be proven due to new discoveries Tells what happened

Collaboration / Communication  When scientists share ideas by collaboration and communication, they increase the likelihood of a successful outcome  Collaboration – Fig. 1.21, p. 24  How is communication done?  Is the Internet reliable information? –

Problem Solving in Chemistry  We are faced with problems each day, and not just in chemistry  A solution (answer) needs to be found  Trial and Error may work sometimes?  But, there is a method to problem solving that works better, and these are skills that no one is born knowing – they need to be learned.

Problem Solving in Chemistry  Effective problem solving usually involves two general steps: 1)Developing a plan 2)Implementing that plan  The skills you use to solve a word problem in chemistry are NOT different from those techniques used in shopping, cooking, or planning a party.

Solving Numeric Problems  Measurements are an important part of chemistry; thus many of our word problems involve use of mathmatics –Word problems are real life problems, and sometimes more information is presented than needed for a solution  Following skills presented will help you become more successful

Solving Numeric Problems  The three steps we will use for solving a numeric word problem are: 1)Analyze 2)Calculate 3)Evaluate  The following slides tell the meaning of these three steps in detail. Let’s learn how to ACE these numeric word problems!

Solving Numeric Problems 1)Analyze: this is the starting point –Determine what are the known factors, and write them down on your paper! –Determine what is the unknown. If it is a number, determine the units needed –Plan how to relate these factors- choose an equation; use table or graph  This is the heart of successful problem solving techniques – it is the PLAN

Solving Numeric Problems 2)Calculate: perform the mathematics –If your plan is correct, this is the easiest step. –Calculator used? Do it correctly! –May involve rearranging an equation algebraically; or, doing some conversion of units to some other units.

Solving Numeric Problems 3)Evaluate: – the finishing step –Is it reasonable? Make sense? Do an estimate for the answer, and check your calculations. –Need to round off the answer? –Do you need scientific notation? –Do you have the correct units? –Did you answer the question ?

Solving Conceptual Problems  Not all word problems in chemistry involve doing calculations  Nonnumeric problems are called conceptual problems – ask you to apply concepts to a new situation  Steps are: 1)Analyze and 2) Solve  Plan needed to link known to unknown, but no checking units or calculations  Do Conceptual Problem 2.1 on page 46