Gen Chem Module 1 Vocabulary Flashcards: Scientific Method, Measurements, and Dimensional Analysis

Vocabulary flashcards covering key terms from the lecture notes (Modules 1A–1D).

Scientific Method

A systematic, iterative process of asking questions, forming hypotheses, testing with experiments or problem solving, and drawing conclusions while evaluating potential sources of error.

Hypothesis

A testable, educated guess about a relationship between variables that can be tested by experiments.

Theory

A well-supported explanation of observations that explains phenomena and can integrate multiple hypotheses and laws.

Law

A concise description of a natural phenomenon, often expressed mathematically, that reliably describes observations.

Observation

A factual statement about the natural world obtained through senses or instruments.

Question

A query that drives investigation and the formulation of hypotheses.

Experiment

A controlled procedure designed to test a hypothesis or predict outcomes.

Element Symbol

A one- or two-letter abbreviation for a chemical element; first letter is capitalized.

Element Name

The name of a chemical element (e.g., Hydrogen, Iron).

Measurement

A quantitative observation consisting of a number and a unit, typically with an associated uncertainty.

Uncertainty

The doubt in a measurement, represented by the estimated final digit.

Significant Figures

Digits in a measurement that carry meaning about its precision; rules determine which digits are significant.

Exact Numbers

Numbers with infinite significant figures, such as counted values or defined quantities.

Accuracy

Closeness of a measured value to the true value.

Precision

Closeness of repeated measurements to each other.

Random Error

Unpredictable fluctuations that tend to average out with many measurements.

Systematic Error

Consistent bias in measurements due to instrument or method; directional (too high or too low).

Conversion Factor

A ratio equal to 1 used to express the equality of two different units and to convert between them.

Dimensional Analysis

A problem-solving technique using conversion factors to relate units and obtain the desired units.

SI Base Unit

The fundamental units in the SI system (e.g., meter, kilogram, second, kelvin).

Derived Unit

A unit obtained from base units, such as the joule (kg·m^2/s^2).

Mass

Quantity of matter in an object; SI unit is the kilogram (kg).

Length

Distance; SI unit is the meter (m).

Time

Duration; SI unit is the second (s).

Temperature

Thermal energy measure; SI unit is the Kelvin (K).

Volume

Amount of space occupied; SI unit for common use is the liter (L); 1 mL = 1 cm^3; 1 dm^3 = 1 L.

Kelvin

SI unit of temperature; 0 K = absolute zero; uses no degree symbol; relation to Celsius: K = C + 273.15.

Celsius

Temperature scale; relation to Kelvin: C = K − 273.15.

Fahrenheit

Temperature scale; relation to Celsius: F = (9/5)C + 32.

SI Prefixes

Multipliers used with units (tera to pico); prefixes are placed in front of the base unit (e.g., kilo = 10^3, milli = 10^-3).

1 mL = 1 cm^3

Volume equivalence: 1 milliliter equals 1 cubic centimeter; 1 L equals 1 dm^3.

Kinetic Energy

Energy of motion; KE = 1/2 m v^2.

Joule

SI unit of energy; derived unit: 1 J = 1 kg·m^2/s^2.

Dimensional Analysis Steps

Five steps: 1) State what you want, 2) State what you’re given, 3) Strategize, 4) Solve, 5) Double-check.

Percent by Mass

A way to express composition as a percent of total mass; used as a conversion factor (e.g., 92.5 g Ag per 100 g alloy).

Density

Mass per unit volume; units such as g/mL or kg/dm^3; used to relate mass and volume.

Nitrate

NO3−; a common polyatomic anion.

Cation

Positively charged ion.

Anion

Negatively charged ion.

Polyatomic Ion

An ion composed of two or more atoms covalently bonded, carrying a net charge.