Chapter 1: Introduction – Matter & Measurement (General Chemistry Study Notes)

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Classification of Matter

Concept: Classification of Matter

Matter is anything that occupies space and has mass. In chemistry, matter is classified based on its composition and properties.

Pure Substances: Matter with a fixed composition. Includes elements and compounds.
Mixtures: Matter composed of two or more substances physically combined. Can be homogeneous (uniform composition) or heterogeneous (non-uniform composition).

Type	Definition	Example
Element	Pure substance of one kind of atom	Gold (Au)
Compound	Pure substance of two or more elements chemically bonded	Water (H2O)
Homogeneous Mixture	Uniform composition throughout	Salt water
Heterogeneous Mixture	Non-uniform composition	Sand and iron filings

Example: Air is a homogeneous mixture; granite is a heterogeneous mixture.

Physical and Chemical Changes

Concept: Physical Changes

Physical changes alter the state or appearance of matter without changing its composition.

Examples: Melting ice, dissolving sugar in water, boiling water.

Concept: Chemical Changes

Chemical changes result in the formation of new substances with different compositions.

Examples: Burning wood, rusting iron, cooking an egg.

Reversible and Irreversible Changes

Concept: Phase Changes

Phase changes (e.g., melting, freezing, boiling) are typically reversible physical changes.

Reversible Change: Can be undone (e.g., freezing and melting water).
Irreversible Change: Cannot be undone (e.g., burning paper).

Change Type	Example
Reversible	Melting ice
Irreversible	Cooking an egg

Chemical and Physical Properties

Concept: Chemical Properties

Chemical properties describe a substance's ability to undergo chemical changes.

Examples: Reactivity with acids, flammability, oxidation.

Concept: Physical Properties

Physical properties can be observed without changing the chemical identity of a substance.

Examples: Color, density, melting point, boiling point.

Intensive vs. Extensive Properties

Concept: Intensive Properties

Intensive properties do not depend on the amount of substance present.

Examples: Density, melting point, boiling point, color.

Concept: Extensive Properties

Extensive properties depend on the amount of substance present.

Examples: Mass, volume, length.

Property Type	Depends on Amount?	Examples
Intensive	No	Density, temperature
Extensive	Yes	Mass, volume

SI Units and Measurements

Concept: SI Base Units

The International System of Units (SI) is the standard for scientific measurements.

Physical Quantity	Name	Symbol
Length	meter	m
Mass	kilogram	kg
Time	second	s
Temperature	kelvin	K
Amount of substance	mole	mol
Electric current	ampere	A
Luminous intensity	candela	cd

Concept: Perimeter, Area & Volume

Measurements of length, area, and volume are fundamental in chemistry.

Area:
Volume (rectangular):
Volume (cylinder):

Metric Prefixes

Concept: Metric Prefixes

Metric prefixes are used to express multiples or fractions of base units.

Prefix	Symbol	Multiplier
kilo	k
centi	c
milli	m
micro	\mu
nano	n

Example: 1 kilometer (km) = meters (m).

Temperature and Temperature Conversion

Concept: Temperature

Temperature measures the average kinetic energy of particles in a substance.

Kelvin (K): SI unit for temperature.
Celsius (°C): Commonly used in chemistry.
Fahrenheit (°F): Used in the United States.

Temperature Conversion Formulas

Scientific Notation

Concept: Scientific Notation

Scientific notation expresses very large or small numbers in the form .

Coefficient: Number between 1 and 10.
Exponent: Power of 10.

Example:

Significant Figures

Concept: Significant Figures

Significant figures are the digits in a measurement that are known with certainty plus one estimated digit.

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: 0.00340 has 3 significant figures.

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.

Conversion Factors and Dimensional Analysis

Concept: Conversion Factors

Conversion factors are ratios used to express a quantity in different units.

Example: 1 inch = 2.54 cm

Concept: Dimensional Analysis

Dimensional analysis is a method for converting between units using conversion factors.

Set up the calculation so that units cancel appropriately.
Multiply by conversion factors until the desired unit is obtained.

Example: To convert 115 min to hours:

Density

Concept: Density

Density is the amount of mass per unit volume of a substance.

Formula:
Units: g/cm3 for solids and liquids; g/L for gases.

Example: If a metal has a mass of 21.4 g and a volume of 10.0 cm3, its density is .

Density of Geometric Objects

For regular shapes, calculate volume using geometric formulas.
Cube:
Sphere:

Density of Non-Geometric Objects: Water Displacement

Volume of irregular objects can be found by water displacement.
Volume displaced = Final water level - Initial water level

Example: If water rises from 200 mL to 265 mL when an object is submerged, the object's volume is 65 mL.

Additional info: These notes cover all major introductory concepts in Chapter 1 of General Chemistry, including matter classification, properties, measurement, and calculation techniques essential for laboratory and theoretical work.