Measurement and Calculations in Chemistry – VOCAB Flashcards

Vocabulary flashcards covering measurement concepts, base SI units, SI prefixes, significant figures rules, uncertainty, and dimensional analysis from the notes.

Measurement

A quantitative observation consisting of a number and a scale (unit).

Fundamental SI Units

Base units used in the SI system: kilogram (mass), meter (length), second (time), kelvin (temperature), ampere (electric current), mole (amount of substance).

Kilogram

SI unit of mass; symbol kg.

Meter

SI unit of length; symbol m.

Second

SI unit of time; symbol s.

Kelvin

SI unit of absolute temperature; symbol K.

Ampere

SI unit of electric current; symbol A.

Mole

SI unit of amount of substance; symbol mol.

Prefix

A group of letters added to a unit to denote a multiple or fraction of 10^n (e.g., kilo-, milli-, nano-).

Exa

Prefix meaning 10^18; symbol E.

Peta

Prefix meaning 10^15; symbol P.

Kilo

Prefix meaning 10^3; symbol k.

Deci

Prefix meaning 10^-1; symbol d.

Centi

Prefix meaning 10^-2; symbol c.

Milli

Prefix meaning 10^-3; symbol m.

Micro

Prefix meaning 10^-6; symbol μ.

Nano

Prefix meaning 10^-9; symbol n.

Leading zeros

Zeros that precede all nonzero digits; do not count as significant figures.

Captive zeros

Zeros between nonzero digits; always count as significant figures.

Trailing zeros

Zeros at the right end; significant only if the number contains a decimal point.

Significant figures

Digits that carry meaning in a measurement, including nonzero digits, captive zeros, and trailing zeros with a decimal point.

Exact numbers

Numbers with an infinite number of significant figures, such as defined conversion factors or counted items.

Uncertainty in measurement

The estimated digit in a measurement; measurements always have some uncertainty; record all certain digits and the first estimated digit.

Buret

Laboratory glass tube for measuring liquids; volume is read at the bottom of the liquid curve (meniscus).

Meniscus

The curved surface of a liquid in a tube; reading is taken at the bottom of the curve.

Accuracy

How close a measurement is to the true value.

Precision

How closely repeated measurements of the same quantity agree with each other.

Dimensional Analysis

A method for converting between unit systems using conversion factors to cancel unwanted units and obtain desired units.