Unit 1 and Unit glossaries
accuracy
how close a measurement is to an accepted, true value.
controlled variable
a factor in an experiment that is being held constant or the same for all trials
conversion factor
an equivalency statement that allows you to convert between two different units of measure
dependent variable
what you measure in the experiment and what is affected during the experiment (responds to the independent variable)
hazard/warning symbol
recognizable symbols designed to warn about dangerous materials, locations, or objects
hypothesis
a proposed explanation made on the basis of limited evidence as a starting point for further investigation (if/then statement)
independent variable
a variable whose variation does not depend on that of another
Material Safety Data Sheet (MSDS)
a document that contains information on the potential health effects of exposure to chemicals, or other potentially dangerous substances, and on safe working procedures when handling chemical products
precision
how close repeated measurements are to each other
scientific notation
the way that scientists easily handle very large numbers or very small numbers
significant figure
all the nonzero digits of a number and the zeros that are included between them or that are final zeros and signify accuracy
SI units
a standard international system of units
theory
a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation
chemical change
a change that happens when a substance creates something new after going through a chemical reaction
chemical property
a property that must go through a chemical change in order to be tested
chromatography
physical separation of a mixture using the ability for a compound to dissolve
compound
multiple elements chemically combined in specific predictable ratios
compressable
can be compressed into a smaller volume
definite
is defined, or cannot change
element
a single atom located on the Periodic Table
extensive property
a property that is dependent upon amount of substance
heterogeneous mixture
a mixture where the various components are not uniformly mixed throughout the substance
homogeneous mixture
a mixture where the various components are uniformly mixed throughout the substance
incompressible
cannot be compressed
indefinite
is not defined, or can change
intensive property
a property that is not dependent upon the amount of substance
matter
anything that has both mass and takes up space
physical change
a change that happens to a substance that does not change the molecular composition
physical property
a property that can be tested through the use of a physical change
pure substance
uniform in molecular composition throughout a substance
solution
a homogenous mixture