General Chemistry I Chapter 1 Keys Studying Chemistry

Vocabulary flashcards covering key terms and concepts from Chapter 1 notes on studying chemistry, matter, energy, measurement, SI units, and significant figures.

Chemistry

The study of matter, its properties, the changes matter undergoes, and the energy associated with these changes.

Matter

Anything that has both mass and volume—the “stuff” of the universe.

Composition

The types and amounts of simpler substances that make up a sample of matter.

Properties

Characteristics that give each substance its unique identity.

Solid

A state of matter with fixed shape and fixed volume; can be hard or soft, rigid or flexible.

Liquid

A state of matter with a shape that conforms to the container and a fixed volume; has an upper surface.

Gas

A state of matter with no fixed shape or volume and no surface.

Physical property

A property a substance shows by itself without interacting with another substance (e.g., color, melting point, density).

Chemical property

A property a substance shows as it interacts with or transforms into other substances (e.g., flammability, corrosiveness).

Physical change

A change in which the composition remains the same; physical state changes are typical examples.

Chemical change

A change in which the composition changes and new substances are formed.

Observation

A natural phenomenon or measured event.

Hypothesis

A tentative proposal that explains observations.

Experiment

A procedure to test a hypothesis; measures one variable at a time.

Model (Theory)

A set of conceptual assumptions that explains data from experiments and predicts related phenomena.

Natural law

An observation that is universally consistent and can be stated as a law.

Energy

The ability to do work; it is conserved and can be converted from one form to another.

Potential energy

Energy due to position or composition of an object.

Kinetic energy

Energy due to the movement of an object.

Total energy

The sum of potential energy and kinetic energy.

Gravitational potential energy

Potential energy associated with height in a gravitational system.

Chemical potential energy

Potential energy stored in chemical bonds; energy difference between fuels and products.

The Scientific Approach: Developing a Model

A process where hypotheses are revised and models are altered based on experimental results.

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A tentative proposal that explains observations.

Experiment

A procedure to test a hypothesis; measures one variable at a time.

Model (theory)

Set of conceptual assumptions that explains data and predicts related phenomena.

Observation

A natural phenomenon or measured event used to test hypotheses.

SI base units

Seven fundamental units: kilogram (mass), meter (length), second (time), kelvin (temperature), mole (amount of substance), ampere (electric current), candela (luminous intensity).

Mass

SI base unit: kilogram (kg).

Length

SI base unit: meter (m).

Time

SI base unit: second (s).

Temperature

SI base unit: kelvin (K).

Amount of substance

SI base unit: mole (mol).

Electric current

SI base unit: ampere (A).

Luminous intensity

SI base unit: candela (cd).

Common decimal prefixes (SI)

Prefixes used to scale units (e.g., kilo-, centi-, milli-, micro-, nano-).

cm³ and mL

A cubic centimeter (cm³) is the same volume as 1 mL; 1 L = 1000 mL.

1 cm³ = 1 mL

Equivalent volume units for a cube 1 cm on each side.

1 L

Equals 1000 mL or 1000 cm³.

1 inch = 2.54 cm (exact)

Exact conversion between inches and centimeters.

1 mile = 1.609 km

Conversion between miles and kilometers.

Density

Mass per unit volume; a characteristic physical property.

Extensive property

Property that depends on the amount of substance (e.g., mass, volume).

Intensive property

Property that does not depend on amount (e.g., density).

Water density (approx.)

0.998 g/cm³ at room temperature (example from table).

Exact numbers

Numbers with no uncertainty (e.g., 1000 mg = 1 g; 60 min = 1 hr; 2.54 cm = 1 in).

Temperature scales

Celsius (°C), Kelvin (K), Fahrenheit (°F); Kelvin is the absolute scale (0 K).

K to °C relation

K = °C + 273.15.

°C to °F relation

°F = (9/5)×°C + 32.

Significant figures

Digits that carry meaning; the rightmost digit is an estimate.

Rules for significant figures (nonzero digits)

Nonzero digits are always significant.

Zeros between nonzero digits

Zeros between nonzero digits are significant.

Trailing zeros with decimal point

Trailing zeros to the right of a decimal point are significant.

Leading zeros

Leading zeros to the left of the first nonzero digit are not significant.

Significant figures in calculations (multiplication/division)

Result should have as many SFs as the factor with the fewest SFs.

Significant figures in calculations (addition/subtraction)

Result should have same number of decimal places as the measurement with the fewest decimal places.

Exact numbers and SFs

Exact numbers do not affect the number of significant figures in calculations.

Precision

How close a set of measurements is to each other.

Accuracy

How close measurements are to the true value.

Systematic error

Bias that shifts all measurements in one direction.

Random error

Unpredictable fluctuations that occur in measurements.