a technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of a fixed substrate
chromatography
substance
matter that has a definite composition; also known as a chemical
the SI base unit for mass
kilogram
experiment
a set of controlled observations that test the hypothesis
Lead
Element
the physical forms in which all matter naturally exists on Earth--most commonly as a solid, a liquid, or a gas
states of matter
a chart that organizes all known elements into a grid of horizontal rows (periods) and vertical columns (groups or families) arranged by increasing atomic number
periodic table
crystallization
a separation technique that produces pure solid particles of a substance from a solution that contains the dissolved substance
When one substance changes identity, it exhibits a(n) __________.
intensive property
physical property
chemical property
extensive property
distillation
a technique that can be used to physically separate most homogeneous mixtures based on the differences in the boiling points of the substances involved
refers to how close a measured value is to an accepted value
accuracy
technology
the practical use of scientific information
refers to how close a series of measurements are to one another; precise measurements show little variation over a series of trials but might not be accurate
precision
the SI base unit of temperature
Kelvin
one that does not have a uniform composition and in which the individual substances remain distinct
heterogeneous mixture
the ability or inability of a substance to combine with or change into one or more new substances
chemical property
physical change
a type of change that alters the physical properties of a substance but does not change its composition
the SI base unit for length
meter
the metric unit for volume equal to one cubic decimeter
liter
Chlorine Bleach
Compound
mass
a measure that reflects the amount of matter
Water
Compound
a form of matter that flows, has constant volume, and takes the shape of its container
liquid
a technique that uses a porous barrier to separate a solid from a liquid
filtration
a process involving one or more substances changing into new substances; also called a chemical reaction
chemical change
a physical blend of two or more pure substances in any proportion in which each substance retains its individual properties; can be separated by physical means
mixture
a measure of an amount of matter and also the effect of Earth's gravitational pull on that matter
weight
the ratio of an error to an accepted value
percent error
Hydrogen
Element
a pure substance that cannot be broken down into simpler substances by physical or chemical means
element
a unit defined by a combination of base units
derived unit
In the figure, the volume of hydrogen gas is twice the volume of oxygen gas. What is the mass relationship between hydrogen and oxygen gas?
More information is required.
The hydrogen gas is half as massive as the oxygen gas.
There is no relationship because gasses have no mass.
The hydrogen gas is twice as massive as the oxygen gas
the energy-requiring process by which a solid changes directly to a gas without first becoming a liquid
sublimation
law of multiple proportions
states that when different compounds are formed by the combination of the same elements, different masses of one element combine with the same mass of the other
the amount of mass per unit volume
density
a chemical combination of two or more different elements; can be broken down into simpler substances by chemical means and has properties different from those of its component elements
compound
Which is not a scientific law?
acid ionization constant
Newton's F = m × a
Kepler's law of area
Einstein's E = mc²
the number of all known digits reported in measurements plus one estimated digit
significant figure
List three examples of physical properties.
example: density, color, taste, hardness, and melting point
A characteristic that can be observed or measured without changing the sample's composition is ________________.
a chemical property
a gaseous property
a physical property
a crystalline property
one that has a uniform composition throughout and always has a single phase; also called a solution
homogeneous mixture
Copper
Element
independent variable
in an experiment, the variable that the experimenter plans to change
scientific notation
expresses any number as a number between 1 and 10 (known as a coefficient multiplied by 10 raised to a power (known as an exponent)
quantitative data
numerical information describing how much, how little, how big, how tall, or how fast
Which of the following is a compound?
neon
steel
water
crude oil
an explanation supported by many experiments; is still subject to new experimental data, can be modified, and is considered valid it if can be used to make predictions that are proven true
theory
a defined unit in a system of measurement that is based on an object or event in the physical world and is independent of other units
base unit
law of definite proportions
states that, regardless of the amount, a compound is always composed of the same elements in the same proportion by mass
the SI base unit for time
second
chemistry
the study of matter and the changes that it undergoes
a characteristic of matter that can be observed or measured without changing the sample's composition--for example, density, color, taste, hardness, and melting point
physical property
a uniform mixture that can contain solids, liquids, or gases; also called a homogeneous mixture
solution
graph
a visual display of data, such as a circle graph, line graph, or bar graph
scientific method
a systematic approach used in scientific study; an organized process used by scientists to do research and to verify the work of others
applied research
a type of scientific investigation that is undertaken to solve a specific problem
Neon
Element
qualitative data
information describing color, odor, shape, or some other physical characteristic
a form of matter that has its own definite shape and volume, is incompressible, and expands only slightly when heated
solid
control
in an experiment, the standard that is used for comparison
hypothesis
a tentative, testable statement or prediction about what has been observed
model
a visual, verbal, and/or mathematical explanation of data collected from many experiments
Which of the following is a vapor?
oxygen
hydrogen
helium
steam
gaseous state of a substance that is a liquid or a solid at room temperature
vapor
Periods are ___________ on the periodic table.
right to left diagonals
vertical columns
left to right diagonals
horizontal rows
law of conservation of mass
states that mass is neither created nor destroyed during a chemical reaction but is conserved
a percentage determined by the ratio of the mass of each element to the total mass of the compound
percent by mass
dependent variable
in an experiment, the variable whose value depends on the independent variable
a form of matter that flows to conform to the shape of its container, fills the container's entire volume, and is easily compressed
gas
conclusion
a judgment based on the information obtained
a transition of matter from one state to another
phase change
matter
anything that has mass and takes up space
Which of the following is not a state of matter?
gas
solid
liquid
density
pure research
a type of scientific investigation that seeks to gain knowledge for the sake of knowledge itself