Size and Scale: Scientific Notation and Significant Figures

Vocabulary flashcards covering measurements, scientific notation, significant figures, and types of experimental errors based on the Senior High School Chemistry lecture.

Accuracy

Indicates on how close a measurement is to the true or accepted value.

Precision

Refers to the closeness of measurements within a set of data and the consistent results of repeated measurements.

Scientific Notation

A simple way to write and keep track of very large or very small numbers without having to deal with a lot of zeroes, following specific rules for base, exponent, and coefficient.

Mantissa

The part of a scientific notation expression that carries the rest of the significant digits of the number.

Significant Figures

The number of digits in a given value or a measurement, necessary to decide the accuracy and precision of measurement, calculated as all certain digits plus one uncertain digit.

Counted Numbers

One of three kinds of numbers in chemistry, these are expressed as exact whole numbers, such as $5$ test tubes or $12$ books.

Defined Numbers

Exact numbers that are not always whole numbers, such as $12\,\text{inches per foot}$ or $2.54\,cm$ in one inch.

Measured Numbers

Numbers obtained from reading measuring devices that are never exact.

Mass

The amount of matter in an object; it is a fixed quantity that is independent of the object’s location.

Weight

The pull of gravity on an object that depends on the object’s location.

Volume

The amount of space occupied by an object, calculated for regular solids as $V = lwh$.

Water Displacement Method

A method used to measure the volume of irregular shaped solids or solids with hollow interiors.

Density ($\rho$)

An intrinsic property of matter defined as mass ($m$) per unit of volume ($V$) it occupies, expressed as $\rho = \frac{m}{V}$.

Random Errors

Unpredictable variations in measurement due to uncontrollable factors such as environmental or instrument conditions, which affect precision but can be reduced by averaging multiple trials.

Systematic Errors

Consistent and repeatable errors that affect accuracy by shifting measurements in one direction, and can be corrected if the cause is identified.

Instrumental Error

A type of systematic error caused by failure or imperfection of measuring devices.

Method Error

A type of systematic error caused by non-ideal chemical or physical behaviour of the reaction system.

Personal Error

A type of systematic error caused by the incompetence of the experimenter.

Gross Errors

Mistakes made by the experimenter due to carelessness and misunderstanding, which can severely distort results and lead to outliers.