General Chemistry: Units, Matter, and Separation Techniques Flashcards

Vocabulary practice flashcards covering measurements, significant figure rules, phase changes, separation techniques, and periodic table group characteristics based on lecture notes.

SI Base Units

Standard units of measurement including mass in kilograms ($\text{kg}$), length in meters ($\text{m}$), time in seconds ($\text{s}$), and temperature in Kelvin ($\text{K}$).

Meniscus

The curved upper surface of a liquid in a tube, which should be read at the bottom when measuring volume in a graduated cylinder.

Beaker

A common piece of laboratory glassware that is considered the least precise tool for measuring volume.

Burette

A laboratory instrument used to dispense liquids where volume is read downwards.

Volumetric Flask

Laboratory glassware designed specifically for making exact chemical solutions.

Significant Figures: Logarithms

A rule stating that for logarithmic values such as $\text{pH}$ or $\text{pOH}$, the significant figures are counted only after the decimal point.

Significant Figures: Multiplication and Division

A rule stating that when multiplying or dividing measurements, the final answer must match the lowest number of significant figures in the calculation.

Significant Figures: Addition and Subtraction

A rule stating that when adding or subtracting measurements, the final answer must match the lowest decimal place of the given values.

Fahrenheit to Celsius Conversion

The temperature conversion formula defined as $T_{^\text{o}\text{F}} = 1.80(T_{^\text{o}\text{C}}) + 32$.

Kelvin Conversion

The temperature conversion formula defined as $T_{\text{K}} = T_{^\text{o}\text{C}} + 273$.

Density

An intrinsic physical property that helps identify a substance, defined as mass per unit volume ($D = \frac{m}{V}$) with units in $\text{g/mL}$ or $\text{g/cm}^3$.

Matter

Anything that takes up space and exists as a solid, liquid, or gas.

Homogeneous Mixture

A mixture that is mixed evenly throughout, also known as a solution.

Heterogeneous Mixture

A mixture that is mixed imperfectly or unevenly.

Element

A pure substance made of only one type of atom.

Compound

A molecule made up of two or more different elements chemically bonded together.

Molecule

A chemical structure composed of two or more atoms joined together; all compounds are molecules, but not all molecules are compounds.

Physical Property

A physical characteristic or measurement of a substance.

Chemical Property

The capability of a substance to undergo chemical reactions.

Physical Change

A change in a physical property without changing the composition of the substance, such as phase changes.

Chemical Change

An irreversible change that forms a new substance through a chemical reaction, such as rusting or burning.

Distillation

A separation method for liquid mixtures with different boiling points based on volatility, where the more volatile liquid with the lower boiling point evaporates first.

Volatility

The tendency of a substance to become a gas.

Filtration

A separation technique used to separate an insoluble solid from a liquid.

Decantation

An inaccurate separation technique used to separate substances based on density.

Evaporation (Separation Method)

A process used to separate a solid dissolved in a liquid.

Chromatography

A separation technique involving two phases: a stationary solid phase (paper or beads) and a mobile liquid phase.

Paper Chromatography

A technique where a dotted liquid mixture on a solid paper phase separates as the mobile liquid solution moves up the paper via capillary action.

Column Chromatography

A technique where a solid stationary phase of beads is packed into a column and a mobile liquid phase soaks down through it to move separated substances downwards.

Alkali Metals

Group 1 elements that are highly reactive, malleable, and good conductors of electricity and heat.

Alkaline Earth Metals

Group 2 reactive metals with chemical properties similar to alkali metals.

Halogens

Nonmetal elements that naturally exist as paired diatomic molecules.

Noble Gases

Nonmetal elements that are nonreactive.

Nonmetal Characteristics

Properties typical of nonmetals, including being brittle, dull, poor conductors of electricity and heat, and having lower melting points.

Metalloids

Elements that are shiny or brittle and act as semiconductors, such as Silicon used in technology.

photoelectric effect

Specific frequency of light is needed to cause emission of electrons

emission

released electrons (specific frequency of light is needed)

absorption

atoms of a solid liquid or gas enter the bulk phase of another substance

wavelength

distance between two peaks

frequency

Number of waves per second

pure substances

these have fixed compositions, one set of intristic, physical properties (density, MP, BP) and can be separated only by chemical means

chemistry measurements

mass: grams

volume: liters

length: cm

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