Video Lecture: Measurements, Uncertainty, and Atomic Theory - VOCABULARY Flashcards

Vocabulary flashcards covering units, accuracy/precision, uncertainty, measurement tools, significant figures, unit conversions, and atomic theory.

Meter (m)

SI base unit of length.

Kilogram (kg)

SI base unit of mass.

Second (s)

SI base unit of time.

Kelvin (K)

SI base unit of temperature.

Ampere (A)

SI base unit of electric current.

Mole (mol)

SI base unit of amount of substance.

Candela (cd)

SI base unit of luminous intensity.

Newton (N)

SI unit of force.

Pascal (Pa)

SI unit of pressure (1 Pa = 1 N/m^2).

Joule (J)

SI unit of energy (work).

Accuracy

Closeness of a measurement to the true value.

Precision

Closeness of measurements to each other (reproducibility).

Calibration

Process of configuring an instrument so measurements are accurate and consistent.

Absolute error

Measured value minus true value.

Relative error

Absolute error divided by the true value, often shown as a percentage.

Systematic error

A bias that consistently shifts measurements in one direction due to instrument or method.

Random error

Unpredictable variations due to human factors or instrument limitations.

Uncertainty

Range or interval indicating where the true value is estimated to lie.

Miniscus

The curved surface of a liquid in a graduated cylinder read at eye level.

Graduated cylinder

Glassware used to measure liquid volumes with marked intervals.

Graduated pipette

Pipette with marks for delivering variable volumes.

Volumetric pipette

Pipette designed to deliver a single, precise volume.

Significant figures

Digits that carry meaning about the precision of a measurement.

Leading zeros

Zeros to the left of the first nonzero digit; not significant.

Trailing zeros with decimal

Zeros after the last nonzero digit are significant when a decimal point is present.

Trailing zeros without decimal

Significance depends on context; not automatically significant.

Exact numbers

Numbers with unlimited significant figures (defined or counted values).

Atom

Basic unit of matter; fundamental building block of elements.

Democritus

Ancient philosopher who proposed the idea of indivisible atoms.

Dalton

Chemist who proposed atomic theory and laws of definite/multiple proportions.

Law of Conservation of Mass

Mass is neither created nor destroyed in chemical reactions.

Law of Definite Proportions

A compound contains the same proportion by mass of elements each time.

Law of Multiple Proportions

If two elements form more than one compound, the ratios of the masses are small whole numbers.

Dalton's Atomic Theory (postulates)

Matter is made of atoms; atoms combine in fixed ratios to form compounds; atoms are rearranged but not created/destroyed in reactions.

Thomson's Plum Pudding Model

Early model where atoms are a diffuse positive charge with embedded electrons.

Rutherford's Nuclear Model

Atom with a tiny, dense nucleus containing protons and neutrons; electrons orbit outside.

Proton

Positively charged subatomic particle in the nucleus.

Neutron

Uncharged subatomic particle in the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus.

Mass number (A)

Total number of protons and neutrons in the nucleus.

Atomic number (Z)

Number of protons in the nucleus.

Isotope

Atoms of the same element with different numbers of neutrons.

Isotopic notation

Notation showing mass number and atomic number (e.g., Sodium-23: 23 Na).

Average atomic mass

Weighted average of isotope masses based on their natural abundances.

Relative atomic mass

Another term for the average atomic mass, relative to carbon-12.

NMR/MRI/CT

Imaging techniques using atomic/nuclear properties (NMR, MRI, CT scans).