Chapter 1: Particles of Matter and Measurement Flashcards

Vocabulary flashcards covering introductory chemistry concepts, scientific method, units of measurement, dimensional analysis, significant figures, measurement errors, and temperature scales.

Observation

The careful noting and recording of natural phenomena.

Hypothesis

A tentative explanation of a single or small number of natural phenomena.

Law

A generally observed natural phenomenon.

Experiment

A test of a hypothesis or theory.

Theory

A general explanation of natural phenomena.

SI Base Units

The fundamental units of measurement in the SI system, including meter ($\text{m}$) for length, kelvin ($\text{K}$) for temperature, second ($\text{s}$) for time, mole ($\text{mol}$) for amount of a substance, and kilogram ($\text{kg}$) for mass.

Derived Units

Combinations of base quantities such as length, mass, time, and temperature (for example, velocity, volume, and density).

Water Displacement Method

A technique used to determine the volume of an irregularly shaped object by placing it in water and measuring the resulting change in water volume ($\Delta V$).

Dimensional Analysis

The conversion of measurements and quantities from one unit to another using conversion factors.

Exact Numbers

Numbers that have no uncertainty and possess an infinite number of significant figures, including counted discrete objects, defined quantities, and integral parts of equations.

Systematic Error

An inherent error, such as poor instrument calibration, that can be identified and eliminated.

Random Error

An error in measurement resulting from limitations in the skill of the experimenter.

Accuracy

Refers to how close experimental measurements are to the correct or accepted answer.

Precision

Refers to the degree of reproducibility of a measured quantity.

Mean

An average calculated by summing a set of related values ($\sum_i x_i$) and dividing the sum by the total number of values ($n$).

Standard Deviation

A measure of the amount of variation or dispersion in a set of related values, calculated as $s = \sqrt{\frac{\sum_i (x_i - \bar{x})^2}{n - 1}}$.

Temperature

A measure of the average amount of kinetic energy of particles in a substance, where a higher temperature indicates greater average kinetic energy.

Celsius Scale

A temperature scale ($^\circ\text{C}$) used in most countries where water freezes at $0^\circ\text{C}$ and boils at $100^\circ\text{C}$.

Kelvin Scale

An absolute temperature scale ($\text{K}$) with no negative values, where $0\,\text{K}$ represents absolute zero.

Absolute Zero

The temperature ($0\,\text{K}$ or $-273.15^\circ\text{C}$) at which molecular motion theoretically stops.

Collect and Organize

The initial step in solving chemical problems where information is sorted by identifying given quantities and units, desired quantities and units, and implied relationships.

Analyze

The problem-solving step where a plan is designed using conversion factors or equations, often by working backwards from the desired outcome.

Solve

The problem-solving step where concept plan operations are executed, ensuring units cancel properly by multiplying numerator terms and dividing by denominator terms.

Think About It

The final problem-solving step where the calculation setup is reviewed to verify that units cancel to the target unit and that the final magnitude is reasonable.