Introduction to Chemistry Dr. Richard Malik Chapter 1 Introduction to Chemistry Dr. Richard Malik

The Stories of Two Chemicals Ozone is formed when oxygen gas is exposed to ultraviolet radiation in the stratosphere forming an ozone layer. Ultraviolet radiation (UV) is harmful to plants and animals. Importance of the Ozone Layer: Ozone absorbs most of the harmful UV radiation before it reaches Earth’s surface.

The Stories of Two Chemicals Chlorofluorocarbons (CFC) Used as coolant for refrigerators Used as propellants in spray cans CFC’s escape into the atmosphere causing a thinning of the ozone layer.

What is Chemistry? Chemistry is the study of the matter, its composition, properties, and the changes it undergoes. Applied chemistry is the using of chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing Pure chemistry gathers knowledge for knowledge’s sake

Which Comes First? Pure Chemistry Applied Chemistry Usually comes first, applied later Called technology Or engineering Pure chemistry can explain behavior that has been used without knowing why Steel swords Can’t be good or bad Can be good or bad depending on use

Mass and Matter? Matter is anything that has mass and takes up space. (Ex. Book) Mass is the amount of matter in an object. Measured in grams (g) Weight- The weight of an object is a measure of the force of gravity on the object. Your weight will change if you move from the North pole to the equator but our mass will stay the same.

Branches of Chemistry Analytical Chemistry -studies composition of substances. Organic Chemistry -compounds containing carbon Inorganic Chemistry -substances without carbon Biochemistry- Chemistry of living things Physical Chemistry studies behavior of substances rates and mechanisms of reactions energy transfers

Applied Chemistry Material Design Plastics Paints Nanotechnology Scale Macroscopic- Big enough to see Microscopic- Too small to see unaided Nanotechnology- manipulating individual atoms and molecules

Applied Chemistry Agriculture Production- fertilizers, soil tests Protection – pesticide, herbicide Medicine Drugs Materials- hips, artificial skin Biotechnology- using organisms as a means of production

Scientific Method A way of solving problems or answering questions. Step 1:Observation- the act of gathering information. Observations can be: Qualitative data- Anything that relates to the five senses. (look, feel, sound, taste, smell) Quantitative data- Numerical information that tells you how much, how little, etc.

Scientific Method (cont.) Step 2:Hypothesis- a testable statement or prediction that explains the cause of the observation, based on research and previous knowledge Step 3: Experiment- a process designed to test the hypothesis. only two possible answers, hypothesis is right or wrong Generates data -observations from experiments.

Scientific Method (cont.) Step 4 Conclusion: A judgment based on the information obtained. Can lead to a theory. Theory - Hypothesis supported by many experiments. Scientific Law- Summary of accepted facts of nature. Step 5 Modify hypothesis - repeat the cycle.

Cycle repeats many times. By you and by others The hypothesis gets more and more certain. Becomes a theory A thoroughly tested model that explains why things behave a certain way. Observations Hypothesis Experiment

Theory can never be proven. It is the best explanation Useful because they predict behavior Help us form mental pictures of processes (models) Observations Hypothesis Experiment

Another outcome is that certain behavior is repeated many times Scientific Law is developed Description of how things behave Usually an equation Law - how Theory- why Observations Hypothesis Experiment

Law Modify Observations Theory (Model) Hypothesis Experiment Prediction Modify Experiment Law Experiment

Variables Controlled experiment- Only want one thing to change at a time in a laboratory. Independent variable- What you change or control directly. Dependent variable – What changes as a result of changing the independent variable. No direct control.

References Dingranso, L, Gregg, K, Hainen, N, & Wistrom, C (2002). Chemistry: matter and change. Columbus, OH: Glencoe/McGraw-Hill. Green, N.D., Mr. Green’s Home Page. Retrieved October 17, 2008 from http://www.tvgreen.com/index.htm