Matter and Measurement: Foundations for General Biology and Chemistry

Matter and Measurement

1.1 Chemistry: The Science of Everyday Experience

Chemistry is the study of matter—its composition, properties, and transformations. Understanding chemistry is essential for biology, as biological processes depend on chemical principles.

• Matter: Anything that has mass and takes up space.

• Examples: Cotton, sand, and medications are naturally occurring substances studied in chemistry and biology.

1.2 State of Matter

Matter exists in three common states: solid, liquid, and gas. Each state has distinct physical properties.

• Solid: Fixed volume and shape; particles are tightly packed and vibrate in place.

• Liquid: Fixed volume but takes the shape of its container; particles are close but can move past each other.

• Gas: No fixed shape or volume; particles are far apart and move freely.

• Example: Water exists as ice (solid), liquid water, and steam (gas).

1.2A Physical and Chemical Properties

Matter is characterized by its physical properties (observable without changing composition) and chemical properties (describe how matter reacts or changes).

• Physical Properties: Color, melting point, density, boiling point.

• Chemical Properties: Flammability, reactivity, ability to rust.

• Physical Change: Change in state or appearance without changing composition.

• Chemical Change: Transformation into a new substance (chemical reaction).

1.3 Classification of Matter

All matter can be classified as either a pure substance or a mixture.

• Pure Substance: Composed of a single component with a constant composition. Examples: Oxygen (O2), Water (H2O).

• Mixture: Contains two or more substances physically combined. Examples: Salt water, Trail mix.

• Element: A pure substance that cannot be broken down into simpler substances. Example: Gold (Au).

• Compound: A pure substance formed by chemically combining elements. Example: Carbon dioxide (CO2).

Type	Examples
Element	Oxygen (O2), Gold (Au)
Compound	Water (H2O), Carbon dioxide (CO2)
Mixture	Salt water, Trail mix

1.4 Measurement

Measurement involves a number and a unit. The metric system is standard in science.

• Length: Meter (m)

• Mass: Gram (g)

• Volume: Liter (L)

1.4A The Metric System

• Base units: Meter (length), gram (mass), liter (volume)

• Prefixes: kilo- (1000x), centi- (1/100x), milli- (1/1000x)

1.4B Measuring Length and Mass

• Mass: Amount of matter in an object (measured in grams).

• Weight: Force that matter feels due to gravity (varies with location).

Property	Mass	Weight
Depends on location?	No	Yes
Unit	Gram (g)	Newton (N)

1.4D Measuring Volume

• Volume: The amount of space an object occupies (measured in liters).

1.5 Significant Figures

Significant figures are the digits in a measured number, including one estimated digit. They reflect the precision of a measurement.

• Rules:

  • All nonzero digits are significant.

  • Zeros between nonzero digits are significant.

  • Leading zeros are not significant.

  • Trailing zeros are significant only if there is a decimal point.

• Example: 21.70 cm has 4 significant figures.

1.5A Determining Significant Figures

• Count all digits except leading zeros and trailing zeros without a decimal.

1.5B Significant Figures in Calculations

• Multiplication/Division: Result has the same number of significant figures as the measurement with the fewest significant figures.

• Addition/Subtraction: Result has the same number of decimal places as the measurement with the fewest decimal places.

1.6 Scientific Notation

Scientific notation expresses numbers as a product of a coefficient and a power of ten.

• Format: $a \times 10^n$

• Example: 1,000 = $1 \times 10^3$

1.7 Problem Solving Using Conversion Factors

Conversion factors are used to convert a quantity in one unit to another unit.

• Example: 1 kg = 2.20 lb

• Set up conversion as a ratio and multiply to solve.

1.9 Temperature

Temperature measures how hot or cold an object is. Common scales: Celsius, Fahrenheit, Kelvin.

• Celsius: Water freezes at 0°C, boils at 100°C.

• Fahrenheit: Water freezes at 32°F, boils at 212°F.

• Kelvin: Absolute zero is 0 K.

1.10 Density and Specific Gravity

Density and specific gravity are used to characterize substances.

• Density: A physical property that relates mass and volume.

• Formula: $\text{Density} = \frac{\text{mass (g)}}{\text{volume (mL or cc)}}$

• Example: Water has a density of 1.0 g/mL at 4°C.

1.10B Specific Gravity

• Specific Gravity: Ratio of the density of a substance to the density of water at 4°C.

• Formula: $\text{Specific gravity} = \frac{\text{density of substance (g/mL)}}{\text{density of water (g/mL)}}$

• Example: Ice floats on water because its specific gravity is less than 1.