Introductory Chemistry – Key Vocabulary

Vocabulary flashcards covering fundamental concepts from the introductory chemistry lecture, including the scientific method, SI units, metric prefixes, scientific notation, and measurement terminology.

Chemistry

The study of matter—its composition, structure, properties, and the changes it undergoes.

Scientific Method

A systematic protocol for developing accepted scientific knowledge; steps include observation, hypothesis, experimentation, and conclusion.

Observation (Scientific Method)

Careful noting and recording of natural phenomena; the first step that sparks a scientific investigation.

Hypothesis

A tentative, testable explanation for an observation, awaiting experimental verification.

Experimentation

Controlled testing designed to support or refute a hypothesis.

Conclusion

The final step of the scientific method summarizing results; may take the form of a theory or scientific law.

Theory (Scientific)

A well-supported explanation of a natural phenomenon; may have competing versions until broadly confirmed.

Scientific Law

A concise, universal statement of a natural relationship (e.g., pressure ∝ 1/volume) accepted as fact by the scientific community.

International System of Units (SI)

Globally agreed-upon set of base units used for scientific measurement and publication.

Meter (m)

SI base unit for length.

Kilogram (kg)

SI base unit for mass.

Second (s)

SI base unit for time.

Kelvin (K)

SI base unit for temperature.

Metric Prefix: kilo- (k)

Represents 10³ (1,000) times the base unit; e.g., 1 kilogram = 1,000 grams.

Metric Prefix: mega- (M)

Represents 10⁶ (1,000,000) times the base unit.

Metric Prefix: centi- (c)

Represents 10⁻² (1/100) of the base unit; e.g., 1 centimeter = 0.01 meter.

Metric Prefix: milli- (m)

Represents 10⁻³ (1/1,000) of the base unit.

Metric Prefix: micro- (µ)

Represents 10⁻⁶ (1/1,000,000) of the base unit.

Metric Prefix: nano- (n)

Represents 10⁻⁹ (1/1,000,000,000) of the base unit.

Scientific Notation

A method for expressing very large or very small numbers as a coefficient (1–10) multiplied by 10 raised to an exponent.

Coefficient (Scientific Notation)

The numeric factor between 1 and 10 in scientific notation (e.g., 2.2 in 2.2 × 10⁴).

Exponent (Scientific Notation)

The power of 10 indicating how many places the decimal moves; positive for large numbers, negative for small numbers.

Positive Exponent

Indicates the decimal moves to the right; the number is larger than one.

Negative Exponent

Indicates the decimal moves to the left; the number is smaller than one.

Multiplying Exponents (Rule)

When multiplying powers of 10, add the exponents: 10ᵃ × 10ᵇ = 10ᵃ⁺ᵇ.

Dividing Exponents (Rule)

When dividing powers of 10, subtract the exponents: 10ᵃ / 10ᵇ = 10ᵃ⁻ᵇ.

Power of a Power

(10ᵃ)ᵇ = 10ᵃᵇ; multiply exponents when raising a power to another power.

Matter

Anything that occupies space (volume) and has mass.

Mass

A measure of the amount of matter in an object; independent of gravity.

Weight

The gravitational force acting on an object’s mass; varies with location (e.g., Earth vs. Moon).

Precision

How closely repeated measurements agree with each other.

Accuracy

How close a measurement is to the true or accepted value.

Estimated Digit

The final, uncertain digit recorded in a measurement; one-tenth of the smallest marked division.