Ch.1 Chemistry in Our Lives: Foundations, Scientific Method, and Scientific Notation

Ch.1 Chemistry in Our Lives

What is Chemistry?

Chemistry is the study of matter, including its properties, composition, and the changes it undergoes. Matter is defined as anything that occupies space due to its volume and has mass. Chemistry is often referred to as "the central science" because it connects and underpins other scientific disciplines such as biology, physics, environmental science, and health sciences.

• Chemistry: The study of matter—its composition, structure, and the changes it undergoes.

• Matter: Anything that occupies space and has mass.

• Interdisciplinary Connections: Chemistry links to molecular biology, pharmacology, radiochemistry, anatomy, physiology, quantum mechanics, ecology, botany, and more.

• Example: The science that studies the physics of rocks and the earth is Geology.

• Example: The science that studies the motor functions and responses of the Venus Fly Trap is Plant Sciences.

The Scientific Method

The scientific method is a systematic procedure used to answer questions, test ideas, and advance scientific knowledge. It involves collecting information, forming hypotheses, conducting experiments, and analyzing data to draw conclusions. The process is iterative and relies on peer review and publication to validate findings.

• Observation: Collecting information from a primary source, either quantitatively (e.g., body temperature) or qualitatively (e.g., patient looks flushed).

• Hypothesis: A proposed and testable explanation for an observation. Answers "What will happen?" and "Why will it happen?"

• Theory: A testable and broad hypothesis supported by a large body of evidence.

• Law: A testable phenomenon that is provably true within the scientific community.

• Falsifiability: Hypotheses and theories can never be proven correct, but they can be disproven.

Steps of the Scientific Method:

1. Make an Observation

2. Ask a Question

3. Formulate Hypothesis & Make Prediction

4. Design & Conduct Experiment

5. Collect & Interpret Data

6. Draw Conclusions

7. Peer Review & Publish

• Example: A scientist observes a new phenomenon and wonders how it happens. The next step is to hypothesize.

• Example: "Gravity is the reason that an object tossed into the air comes back down" is a theory.

• Practice: The best order of steps is: Observation → Hypothesis → Experiment → Data Analysis → Conclusion → Peer Review & Publish.

• Observation Example: Nurse records patient's resting pulse as 32 beats per minute.

• Hypothesis Example: Drinking coffee at night keeps me awake.

Scientific Notation

Scientific notation is used to express very large or very small numbers in a manageable form. It consists of a coefficient, a base (always 10), and an exponent indicating the number of decimal places moved.

• Coefficient: The beginning part of the value, which must be greater than or equal to 1 but less than 10.

• Base: Always 10.

• Exponent: Indicates how many places the decimal was moved; must be a whole number integer.

Converting Scientific Notation to Standard Notation:

• A positive exponent makes the coefficient value larger (moves decimal to the right).

• A negative exponent makes the coefficient value smaller (moves decimal to the left).

• Example: $7.17 \times 10^5 = 717,000$

• Example: $3.25 \times 10^{-7} = 0.000000325$

Converting Standard Notation to Scientific Notation:

• Ensure the coefficient is ≥ 1 and < 10.

• Increasing the coefficient decreases the exponent; decreasing the coefficient increases the exponent.

• Example: $377,000 = 3.77 \times 10^5$

• Example: $0.000101 = 1.01 \times 10^{-4}$

• Example: $707.82 = 7.0782 \times 10^2$

Correct Scientific Notation Format:

• Coefficient must be between 1 and 10.

• Exponent must be a whole number.

• Example: $5.220 \times 10^3$ is correct.