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Chapter 1: Introduction to Chemistry

Chapter 1: Introduction to Chemistry. What is chemistry?. The study of the composition of matter and the changes it undergoes. What is matter? Anything that has mass and occupies space. What’s the Difference Between Mass and Weight?. Weight. Measure of the amount of matter in an object.

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Chapter 1: Introduction to Chemistry

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  1. Chapter 1: Introduction to Chemistry

  2. What is chemistry? • The study of the composition of matter and the changes it undergoes. • What is matter? • Anything that has mass and occupies space.

  3. What’s the Difference Between Mass and Weight? Weight Measure of the amount of matter in an object. Needs a balance. A force that measures the pull of gravity on an object. Needs a scale. Mass

  4. Five Areas of Chemistry • Organic Chemistry: studies all chemicals containing carbon • Inorganic Chemistry: studies chemicals NOT containing carbon • Biochemistry: study of processes in organisms • Analytical Chemistry: studies composition of matter • Physical Chemistry: studies mechanism, rate, and energy transfers in matter during changes

  5. Which area of study matches each of the following? • Developing processes for efficient steel production • Inorganic chemistry • Studying how lack of calcium affects bone growth • Biochemistry • Measuring amount of lead in drinking water • Analytical chemistry • Researching differences between C2H5OH and CH3OH • Organic chemistry • Comparing energy differences needed to walk up or run up steps • Physical chemistry

  6. Two Types of Chemical Research Applied Chemistry Pursuit of chemical knowledge for its own sake “I’ll experiment and see what I discover.” Research for a practical goal or application. “I’m looking for a cure for cancer.” Pure Chemistry

  7. Why Study Chemistry? • Explains the natural world • Energy, medicine, materials, biotechnology, agriculture, environment, universe • Helps prepare for a career • Many different jobs using chemistry • Helps create informed citizens

  8. Antoine Lavoisier • “Father of Modern Chemistry” • Changed chemistry from observations to measurements • Determined that oxygen is needed to burn • Found and named elements • Wrote textbooks • Law of Conservation of Matter • Made very precise balance, great lab • Collaborated scientifically with peers

  9. Scientific Method • Logical, systematic approach to a scientific problem • Observation: using senses to get information • Hypothesis: proposed explanation for an observation • Experiment: procedure to test a hypothesis

  10. Variables in an Experiment Responding (Dependent) Variable What the experimenter changes Often time or temperature Plotted on x-axis The variable observed in an experiment Plotted on y-axis Manipulated (Independent) Variable

  11. What’s the Difference Between a Theory and a Law? Scientific Law Well-tested explanation for a broad set of observations Cannot be proved Theory of Relativity, Big Bang Theory Concise statement summarizing results of many experiments and observations Laws of Gravity, Law of Conservation of Matter Scientific Theory

  12. Observations Hypothesis Theory Experiments May be revised May be modified Scientific Law Summarizes the results of many observations and experiments

  13. Graphing in Chemistry • Graphs display data in a concise form. • Graphs predict trends in data. • Graphs allow extrapolation to points beyond data limits. • Line graphs very common. • Five major parts: title, independent variable, dependent variable, scales for each axis, legend (if needed)

  14. Graph Title • ALWAYS y-axis name vs. x-axis name! • DO NOT use abbreviations in title except for vs. Velocity vs. Time

  15. Independent (Manipulated) Variable • Controlled by experimenter • Includes time, depth, temperature • Placed on x-axis (horizontal axis)

  16. Dependent (Responding) Variable • Directly affected by the independent variable • Changes in response to changes in independent variable • Placed on y-axis

  17. Scales for Each Axis • Must include all data points. • Scale for each axis is dictated by data values. • Axis scales are independent of each other (both do not have to start on same number). • Scales DO NOT have to start at zero! • Scale MUST be consistent on the axis (same interval throughout). • DO NOT USE A BREAK ON THE SCALE!

  18. Example of Scales

  19. Breaks on Axis DO NOT USE A BREAK ON YOUR GRAPH!

  20. Axes Titles and Units • Each axis needs a title and a unit. • Do not abbreviate titles. • Put the unit in parenthesis after the title. Voltage vs. Frequency Voltage vs. Frequency

  21. Legend • Only used when needed for clarity. • Short and concise.

  22. Line of Best Fit Graphs • Frequently used in chemistry. • If data points do not form a straight line, line is drawn as an average through the points. • Draw one thin line using a ruler.

  23. Extrapolation • To infer or estimate by extending or projecting from known information. • Can get information on points not tested in lab. • Make dotted line with a ruler to extend graph.

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