Chapter 1 Chem

Chapter 1: Chemistry in Our Lives

Objectives

  1. Define the term chemistry

    • Chemistry is defined as the science that seeks to understand what matter does by studying the actions of atoms and molecules.

  2. Recognize that all things are made of atoms and molecules.

  3. Describe the activities that are part of the scientific method.

  4. Review math concepts used in chemistry:

    • Place values

    • Positive and negative numbers

    • Solving equations

    • Interpreting graphs

  5. Develop a study plan for learning chemistry and understand how to be a successful beginning chemist.

Chemistry and Matter

Chemistry

  • Chemistry is:

    • The study of composition, structure, properties, and reactions of matter.

Matter

  • Matter is defined as:

    • Anything that has mass and volume.

    • All substances that comprise our world, including:

    • Antacid tablets

    • Water

    • Glass

    • Air

  • Important Note: Matter is composed of atoms and molecules.

Atoms

  • Atoms are:

    • The fundamental building blocks of all matter.

    • The smallest unit of elements.

Molecules

  • Molecules are:

    • Composed of two or more atoms attached via chemical bonds.

    • Example: Isopropyl alcohol.

Properties of Matter

  • The properties of matter are determined by the atoms and molecules that compose it.

Examples of Atoms and Molecules

  1. Carbon dioxide (CO₂)

    • Composed of 1 carbon atom and 2 oxygen atoms.

    • Characteristics make CO₂ a gas at room temperature.

  2. Water (H₂O)

    • Composed of 2 hydrogen atoms and 1 oxygen atom.

    • Characteristics make H₂O a liquid at room temperature.

Chemicals Compose Ordinary Things

  • Chemicals are substances that have the same composition and properties wherever they are found.

    • Everything you can hold or touch is made of chemicals.

    • Examples of everyday items made from chemicals include:

    • Silicon dioxide (glass)

    • Chemically treated water

    • Metal alloy

    • Natural polymers

    • Natural gas

    • Products like Tylenol, toilet paper, and toothpaste.

Detailed Example: Toothpaste Composition

  • Chemical Components:

    1. Calcium carbonate - Used as an abrasive to remove plaque

    2. Sorbitol - Prevents loss of water and hardening of toothpaste

    3. Sodium lauryl sulfate - Used to loosen plaque

    4. Titanium dioxide - Makes toothpaste white and opaque

    5. Triclosan - Inhibits bacteria causing plaque and gum disease

    6. Sodium fluorophosphate - Strengthens tooth enamel against cavities

    7. Methyl salicylate - Provides a pleasant wintergreen flavor.

Concept Check

  • Question: Which of the following does not contain chemicals?

    • A. Fruits.

    • B. Milk.

    • C. Breakfast cereal.

    • D. Sunlight.

The Scientific Method

Definition

  • The scientific method is a way of learning that emphasizes using the senses to produce knowledge through observations and experimentation.

  • It encompasses general principles describing how scientists think.

Overview of the Scientific Method

  1. Make Observations: Involves measuring or observing nature.

  2. Formulate Hypothesis: A tentative explanation of the observations.

  3. Testing through Experiments: Controlled procedures to validate or invalidate hypotheses.

  4. Confirmation and Revision of Theory: If experiments support hypotheses, they may evolve into theories, and if not, they are revised.

  5. Validating Laws: Broad applications of verified theories become laws.

Example of Scientific Thinking

  1. Observation: You visit a friend and experience eye itching and sneezing, noting they have a new cat.

  2. Hypothesis: You might be allergic to cats.

  3. Experiment: Leave the friend's home—if symptoms cease, the hypothesis gains support.

  4. Further Testing: Visit another friend with a cat; if symptoms recur, your hypothesis is reinforced.

  5. Conclusion/Theory: You conclude that you are allergic to cats based on consistent observations.

Concept Check

  • Task: Identify the step of the scientific method:

    • A. A blender doesn't work when plugged in. - Observation

    • B. The blender motor is broken. - Hypothesis

    • C. The plug has malfunctioned. - Hypothesis

    • D. The blender does not work when plugged into a different outlet. - Experiment

    • E. The blender needs repair. - Theory/Conclusion

    • F. Trainer records running 25 min on treadmill. - Observation

    • G. Weight loss attributed to increased exercise. - Hypothesis.

Key Math Skills for Chemistry

Concepts Reviewed

  • Identifying Place Values:

    1. For the number 2518 g:

    • 2518 is comprised of:

      • 2518 = 2 Thousands, 5 Hundreds, 1 Ten, 8 Ones.

    1. For the number 6.407 g:

    • 6.407 is comprised of:

      • 6 = 6 Ones, 4 = 4 Tenths, 0 = 0 Hundredths, 7 = 7 Thousandths.

Positive and Negative Numbers

  • Positive Numbers: > 0

  • Negative Numbers: < 0

  • Multiplication:

    • (+) x (+) = (+)

    • (-) x (-) = (+)

    • (+) x (-) = (-)

  • Division:

    • (+) ÷ (+) = (+)

    • (-) ÷ (-) = (+)

    • (+) ÷ (-) = (-)

Solving Equations Examples

  • Solve for x in the equation: 2x+6=42x + 6 = 4

    • Results in x=−1x = -1.

  • Solve for P in the equation: Pir2=PPi r^2 = P.

Analyzing and Interpretation of Data

  • Key Skill: Identifying patterns in data

  • Example:

    • Mass of Water Sample: 20.0 g

    • Mass of Hydrogen Formed: 2.2 g

    • Mass of Oxygen Formed: 17.8 g

    • Observation: The sum of the masses of oxygen and hydrogen equals the mass of water.

Graph Interpretation

  • A graph illustrates the relationship between two variables.

  • Example: Atmospheric CO₂ levels over years.

    • CO₂ concentration (parts per million) across selected years:

      • In 1960: 318 ppm

      • In 2000: 370 ppm

Beginning Chemist: How to Succeed

  • Key to Learning Chemistry: A commitment to success and a desire to learn.

  • Active learning steps:

    1. Read each Learning Goal for material overview.

    2. Formulate questions based on section titles.

    3. Read to find answers to questions.

    4. Work through sample problems, checking your answers.

  • Study Plan Recommendations:

    • Read chapters prior to lectures.

    • Actively engage in lectures.

    • Review learning objectives

    • Form study groups, and seek help from professors during office hours.

    • Organize self-review sessions and practice problems regularly.

Concept Check

  • Question: Which activity should NOT be part of your chemistry study plan?

    • A: Forming a study group.

    • B: Keeping a problem notebook.

    • C: Completing homework.

    • D: Skipping lectures. - Correct Answer

Wrapping Up!

  • Important:

    • Curiosity and imagination are crucial.

    • Willingness to perform calculations is necessary.

    • A commitment to mastering material is essential.

    • Completing all assignments (homework, quizzes, lab reports) is vital.

    • The mindset of perseverance is key.