Introduction to Chemistry and Matter: Foundations for Biology

Study Guide - Smart Notes

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Density is the ratio of the mass of an oDefining Chemistry

What is Chemistry?

Chemistry is the scientific study of the composition, structure, properties, and changes of matter. It emerged from the experimentation of alchemists and forms the basis for understanding biological and physical processes.

Chemistry: The study of the composition of matter and the changes it undergoes.
Originated from alchemy, which involved early experimentation with substances.

Major Areas of Chemistry

Chemistry is divided into several specialized fields, each focusing on different aspects of matter and its interactions.

Organic chemistry: Study of all chemicals containing carbon.
Inorganic chemistry: Study of chemicals that do not contain carbon.
Biochemistry: Study of the chemistry of living things.
Analytical chemistry: Study of the composition of matter.
Physical chemistry: Study of the mechanisms, rates, and energy transfers that occur when matter changes.

Why Study Chemistry?

To explain natural phenomena and what goes on around us.
To prepare for careers in science, medicine, engineering, and related fields.
To make informed decisions in everyday life.

Historical Roots: Alchemy

Origins and Contributions of Alchemy

Alchemy was practiced in many ancient cultures, including Arabia, China, and Greece. Alchemists sought to transform substances, create gold, and discover potions for eternal life, but also contributed to the understanding of matter.

Developed practical laboratory procedures such as distillation, sublimation, oxidation, and extraction.
Learned and documented the properties of many substances.
Developed tools and techniques still used today, though they lacked logical scientific explanations for changes in matter.

The Scientific Method

Systematic Approach to Scientific Inquiry

Scientists use a systematic approach, known as the scientific method, to solve problems and answer questions about the natural world.

Make observations: Gather information using the senses or instruments.
Formulate hypotheses: Propose explanations based on observations.
Experimenting: Test hypotheses by manipulating variables and collecting data.
- Manipulated variable (independent variable): The variable that is changed.
- Responding variable (dependent variable): The variable that is observed or measured.
- Data can be qualitative (descriptive) or quantitative (numerical).
Draw conclusions: Analyze data to support or refute the hypothesis.

Matter and Its Properties

Definition of Matter

Matter is anything that has mass and takes up space. It is the fundamental substance of the universe, making up all physical objects.

Mass: A measure of the amount of matter an object contains (measured in grams or kilograms).
Volume: A measure of the space occupied by an object (measured in liters, milliliters, or cubic centimeters).

Describing Matter: Physical Properties

Physical properties are qualities or conditions of a substance that can be observed or measured without changing the substance's composition.

Examples: color, boiling point, melting point.

States of Matter

Matter exists in different physical forms called states. The most common states are solid, liquid, and gas.

Solid: Has a definite shape and volume; shape does not depend on the container; particles are tightly packed; almost incompressible; expands slightly when heated.
Liquid: (Additional info: Has a definite volume but takes the shape of its container; particles are less tightly packed than in a solid and can move past each other.)
Gas: (Additional info: Has neither a definite shape nor a definite volume; particles are far apart and move freely.)

Measurement in Science

Measurement and Units

Measurement is fundamental to experimental science. It involves quantifying observations using numbers and units, typically in the SI/Metric System.

Examples: 51 km, 7.62 cm, 451 mL.
Measurements should be both correct (accurate) and reproducible (precise).

Accuracy and Accepted Value

Accuracy refers to how close a measurement is to the actual or true value. The Accepted Value (AV) is the correct value based on reliable references.

Significant Figures

Definition and Importance

Significant figures (sig figs) are all the digits in a measurement that are known with certainty, plus one last digit that is estimated. They are important for expressing the precision of measurements and calculations.

Nonzero digits always count as significant.
Zeros may or may not be significant, depending on their position.
Exact numbers (such as counting numbers or defined conversions) have an infinite number of significant figures and do not limit the precision of calculations.

Rules for Calculations:

When performing calculations, the number of significant figures in the result should reflect the precision of the least precise measurement.

Scientific Notation

Purpose and Format

Scientific notation is used to express very large or very small numbers in a compact form. It consists of a coefficient and a power of ten.

Numbers greater than 1 have a positive exponent.
Numbers less than 1 have a negative exponent.
Example:

Scientific notation helps maintain significant digits in calculations.

Density

Definition and Calculationbject to its volume. It is an intensive property, meaning it does not depend on the amount of substance present.

Formula:
Units: Commonly expressed in or

Density and Temperature

The density of a substance generally decreases as its temperature increases, because volume increases while mass remains the same.

Density and Pressure

The density of a substance generally increases as its pressure increases, because volume decreases while mass remains the same.

Summary Table: Key Properties and Definitions

Term	Definition	Example/Unit
Matter	Anything that has mass and takes up space	Any physical object
Mass	Amount of matter in an object	g, kg
Volume	Space occupied by an object	mL, L, cm3
Density	Mass per unit volume	g/cm3, kg/L
Accuracy	Closeness to true value	Measured vs. accepted value
Significant Figures	Digits that reflect measurement precision	All known digits plus one estimated
Scientific Notation	Compact way to write large/small numbers