Unit-1 Chemistry Study Guide: Lab Safety, Equipment, Scientific Measurement, and Experimental Design

Vocabulary practice flashcards covering laboratory safety, common equipment, scientific notation, mass and density, experimental variables, significant figures, and dimensional analysis.

Wafting technique

The safe method of smelling a chemical by waving vapors toward the nose rather than sniffing directly.

Beaker

Laboratory glassware used for holding, mixing, and heating liquids, providing approximate volume measurements.

Erlenmeyer flask

A laboratory flask used for mixing and holding liquids that can be swirled with less spilling.

Graduated cylinder

A piece of laboratory equipment used for measuring liquid volume accurately.

Meniscus

The curved surface of a liquid in a container; for most aqueous liquids, the measurement is read at the bottom of this curve.

Crucible

A small container used for strongly heating small amounts of solid material.

Watch glass

A shallow concave glass dish used for holding small amounts of substances or evaporating liquids.

Evaporating dish

A piece of laboratory equipment used for evaporating a solvent.

Mortar and pestle

A pair of laboratory tools used for grinding solids into powder.

Scientific notation

A method used to represent very large or very small numbers in the general form $\text{coefficient} \times 10^n$, where the coefficient must be at least $1$ but less than $10$.

Mass

The amount of matter in an object, measured using a balance in units such as grams ($\text{g}$), kilograms ($\text{kg}$), and milligrams ($\text{mg}$).

Volume

The amount of space occupied by an object, commonly measured in liters ($\text{L}$), milliliters ($\text{mL}$), or cubic centimeters ($\text{cm}^3$), where $1\,\text{mL} = 1\,\text{cm}^3$.

Density

A measurement describing how much mass is contained in a certain volume, calculated using the formula $D = \frac{m}{V}$.

Observation

Information obtained using your senses or measuring instruments.

Hypothesis

A testable prediction, commonly written in the format: If __________, then __________, because __________.

Independent Variable

The factor or condition in an experiment that you change on purpose.

Dependent Variable

The factor or condition in an experiment that you measure or observe.

Controlled Variables

Factors in an experiment that are kept the same across trials.

Control Group

A comparison group that does not receive the experimental treatment or independent-variable condition being tested.

Accuracy

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

Precision

How close repeated measurements are to one another.

Significant figures

The digits in a measurement that indicate its precision, consisting of all certain digits plus one estimated digit.

Captive zeros

Zeros trapped between non-zero digits; they are always significant.

Leading zeros

Zeros that appear before the first non-zero digit; they only indicate the position of the decimal point and are not significant.

Trailing zeros

Zeros at the end of a number that are significant if a decimal point is present, but ambiguous in whole numbers without a decimal.

Exact numbers

Counted quantities or defined conversion values that possess an unlimited number of significant figures and do not limit calculation precision.

Dimensional analysis

A mathematical method used to convert from one unit to another by applying conversion factors so that unwanted units cancel out.