Chemical Tools: Experimentation and Measurement - Vocabulary Flashcards

Vocabulary flashcards covering key terms from Chapter 1 and Module sections on macroscopic, microscopic, and symbolic perspectives, SI units, significant figures, and dimensional analysis.

Macroscopic

How we observe the world around us; every substance has a unique set of properties.

Microscopic

All matter is composed of atoms and molecules; study of structures too small to see.

Symbolic

What chemists use to represent atoms, molecules and reactions; elemental symbols and formulas.

Physical Change

Changes form (state) but not chemical make-up (composition).

Chemical Change

Change in chemical make-up (composition).

Solid

Fixed volume and fixed shape.

Liquid

Fixed volume, variable shape.

Gas

Variable volume, variable shape.

Atom

Small particle that cannot be made smaller and still act as a chemical system.

Molecule

Group of atoms held together to form a unit and behave as one unit.

Compound

Substance composed of two or more elements in a fixed, definite proportion.

Law of Conservation of Mass

In a chemical reaction, matter is neither created nor destroyed.

Pure Substance

Made up of only one component.

Mixture

Composed of two or more components in proportions that vary.

Heterogeneous Mixture

Not uniform in appearance and composition.

Homogeneous Mixture

Uniform in appearance and/or composition.

Element

The building blocks; substance that cannot be chemically broken down into simpler substances.

Elemental Symbols

1–2 letter abbreviation; first letter capitalized; based on English/Latin names; used to represent chemical formulas.

SI Base Units

Base units include mass (kg), time (s), distance/length (m), electric current (A), temperature (K), and amount of substance (mol).

Mass

Amount of matter; SI unit is the kilogram (kg).

Time

SI unit is the second (s).

Distance (Length)

SI unit is the meter (m).

Electric Current

SI unit is the ampere (A).

Temperature

SI unit is the Kelvin (K).

Mole

SI unit for amount of substance; number of particles.

Volume

Amount of space occupied; commonly measured in liters (L).

Energy

Capacity to do work; unit is the joule (J).

Kelvin

Absolute temperature scale with no negative values.

Celsius

Temperature scale; used with Kelvin in conversions.

Fahrenheit

Temperature scale; commonly used in the United States.

Metric Prefixes

Prefixes indicating powers of ten: giga (10^9), mega (10^6), kilo (10^3), deci (10^-1), centi (10^-2), milli (10^-3), micro (10^-6), nano (10^-9), pico (10^-12), femto (10^-15).

Density

Density = mass/volume; can be used as a conversion factor (e.g., ethanol ≈ 0.789 g/mL).

Dimensional Analysis

Solving problems by focusing on the units and using conversion factors to cancel units.

Conversion Factor

An equality relating two units used to convert from one unit to another (e.g., 1 in = 2.54 cm).

Exact Numbers

Numbers obtained by counting or defined conversion factors that do not limit the number of sig figs.

Inexact Numbers

Numbers obtained by measurement that contain uncertainty.

Significant Figures

Digits that carry meaning about precision; all certain digits plus the first uncertain digit.

Rounding

Rule: if the first digit removed is ≥ 5, round up; otherwise round down.

Addition/Subtraction Sig Fig Rule

Result has as many decimal places as the least precise measurement.

Multiplication/Division Sig Fig Rule

Result has as many sig figs as the measurement with the least sig figs.

Scientific Notation

Express numbers as mantissa × 10^n to manage large/small values and track sig figs.

Exact vs Inexact Numbers (Supplement)

Exact numbers do not limit sig figs; inexact numbers do.