Chapter 1 - Laboratory Study (Lab Equipment, Measurements, Titration, and Safety)

A comprehensive set of vocabulary-style flashcards covering lab equipment, measurement accuracy and precision, significant figures, titration concepts, centrifugation, calorimetry, safety, and waste disposal.

Beaker

Glassware that is not very accurate for measuring volumes; primarily used for heating, mixing, or stirring liquids.

Graduated cylinder

Glassware used to measure a variety of liquid volumes with moderate precision.

Meniscus

The curved surface of a liquid in a cylinder; read at the bottom of the curve.

Erlenmeyer flask

Flask used for mixing, heating, and stirring; not as accurate for volume measurements.

Boiling flask

Flask primarily used for swirling and heating liquids.

Pipette

Most precise glassware for measuring liquid volumes.

Buret

Glassware commonly used in titrations to deliver measured volumes of liquid.

Stopcock

Valve on a buret that controls the release of liquid.

Test tube

Glass tube used for holding, mixing, and heating small samples; not suitable for precise volume measurements.

Bunsen burner gas flow

The amount of gas supplied controls the flame size.

pH meter calibration

Should be calibrated prior to use.

Digital balance

Instrument used to accurately measure the mass of a solid sample.

Graduated glassware

Glassware with multiple markings indicating different volume levels.

Volumetric glassware

Glassware with a single marking indicating a specific volume.

Volumetric vs graduated accuracy

Volumetric glassware is more accurate than graduated glassware for a single precise volume.

Order of precision

Pipettes > Burets/Volumetric Flasks > Graduated Cylinders > Beakers/Erlenmeyer Flasks.

Weighing directly on digital balance

Never place the sample directly on the balance; use weighing paper or a container.

Digital balance mass-measurement procedure

Turn on the balance, tare with weighing paper or glassware, then place the sample.

Titration

Technique to measure the volume of titrant needed to react completely with another reagent.

Titration error

Deviation of the endpoint from the equivalence point.

Equivalence point

The point at which the added titrant has completely reacted with the reagent.

Endpoint

The point at which the titration is considered complete and is often associated with the equivalence point.

Endpoint color change

Color change observed at the endpoint of a titration.

Centrifugation

Mixture is spun at high speeds; heavier components form a pellet at the bottom.

Supernatant

The liquid on top after centrifugation, above the solid pellet.

Pellet

The solid collected at the bottom after centrifugation.

Calorimetry

Measurement of heat energy released or absorbed during a chemical reaction.

Calorimetry setup

Basic setup: Styrofoam cup with a lid and a thermometer passing through the lid.

Precision

Consistency of repeated measurements; values are close to each other.

Accuracy

Closeness of a measurement to the true value from literature.

Precise but not accurate

Measurements are consistent but biased away from the true value.

Accurate but not precise

Measurements cluster around the true value but are not consistently reproduced.

Both precise and accurate

Measurements are both consistent and close to the true value.

Significant figures

Notation used to describe the uncertainty in a measurement.

Rule 1 of significant figures

Non-zero digits are always significant.

Rule 2 of significant figures

Zeros between non-zero digits are significant.

Rule 3 of significant figures

Trailing zeros in the decimal portion are significant.

Multiplication/Division rule (sig figs)

The result has as many significant figures as the factor with the fewest sig figs.

Addition/Subtraction rule (sig figs)

The result is rounded to the decimal place of the least precise measurement.

Random error

Unpredictable error that can vary in either direction; often due to human factors.

Systematic error

Consistent bias in one direction, often from faulty equipment or procedure.

Safety shower

Used for extensive body exposure to toxic/corrosive chemicals or clothing fires.

Eye wash station

Used to wash chemical splashes in the eyes; rinse for at least 15 minutes.

Disposal of acids/alkalis/water-miscible solutions

Flush down the drain with adequate amounts of water.

Disposal of organic and water-immiscible solutions

Do not drain; dispose in the appropriate laboratory waste bin.

Eating in the lab

Not allowed due to presence of potentially hazardous chemicals.