________ have the same composition and properties regardless of their origin.
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OLEDs
________ (organic light- emitting diodes) are used in high- end cell phone, tablet, and television displays.
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Solar panels
________ are composed of specially treated silicon.
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Chemistry
________ also helps explain matter's qualities in terms of atoms, it's practically infinitesimally small building units.
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pure matter
All ________ is classified ultimately as either an element or a compound.
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Accuracy
________ refers to how closely individual measurements agree with the correct, or "true, "value.
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physical property
A measure of the hotness or coldness of an object, is a(n) ________ that determines the direction of heat flow.
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viscous liquid
Is a(n) ________ used as automobile antifreeze.
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physical appearance
A substance changes its ________ but not its composition.
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distinct properties
(Usually referred to simply as a substance) is matter that has ________ and a composition that does not vary from sample to sample.
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Mixture
________ to be separated is dissolved in the solvent.
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liter
The ________ (L) is larger than a quart and equals a cubic decimeter (dm^3) in chemistry.
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Solid
________ has both a definite shape and a definite volume and is not compressible to any appreciable extent.
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Chemists
________ must manage the composition or structure of molecules to create new substances with various qualities.
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dimensional analysis
In ________, units are multiplied together or divided into each other along with the numerical values.
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physical material
Is the ________ of the universe; it is anything that has mass and occupies space.
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Celsius
The ________ and Kelvin scales have equal- sized units- that is, a kelvin is the same size as a degree ________.
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Kilojoules
________ (kJ) are used to discuss chemical reaction energies because joules are small amounts of energy.
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evaporation of water
The ________ is a physical change.
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Hydrogen
________ and oxygen react to generate 1 g of water, releasing 16 kJ of heat.
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Energy
________ is defined as the capacity to do work or transfer heat.
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meters
Thus, ________ are written in the denominator and centimeters in the numerator.
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National Institutes
Chemists work in universities and government agencies like the ________ of Health, Department of Energy, and Environmental Protection Agency.
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Density
________ is defined as the amount of mass in a unit volume of a substance:
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molecular level
On the ________, each element is composed of only one kind of atom.
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late eighteenth century
The metric system, developed in France during the ________, is used as the system of measurement in most countries.
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sodium chloride
Water and table salt (________) are examples of pure substances.
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Compounds
________ are substances composed of two or more elements; they contain two or more kinds of atoms.
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Precision
________ is a measure of how closely individual measurements agree with one another.
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Liquid
________ has a distinct volume independent of its container, assumes the shape of the portion of the container it occupies, and is not compressible to any appreciable extent.
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SI unit
The ________ for energy is the joule (pronounced "jool), "J, in honor of James Joule (1818−1889), a British scientist who investigated work and heat.
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Mass
________ is a measure of the amount of material in an object.
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terms precision
The ________ and accuracy are often used in discussing the uncertainties of measured values.
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cube
A(n) ________ with an edge length of one meter has a volume of one cubic meter or m3.
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Zero
________ on the Kelvin scale is the temperature at which all thermal motion ceases, a temperature referred to as absolute zero.
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SI base unit of length
The ________ is the meter, a distance slightly longer than a yard.
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ratio of distance
For example, speed is defined as the ________ traveled to elapsed time.
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chemical reaction
(Also called a(n) ________), a substance is transformed into a chemically different substance.
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kinetic energy
For a given velocity, the ________ increases with increasing mass.
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particular type of matter
Is any characteristic that allows us to recognize a(n) ________ and to distinguish it from other types.
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scientific measurements
The units used for ________ are those of the metric system.
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Chemistry
________ is central to our understanding of the world around us.
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Chemists
________ and nature employ the same components and follow the same laws.
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dimensional analysis
Using ________ helps ensure that solutions to problems yield the proper units.
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As we proceed with our study of chemistry, we will find ourselves thinking in two realms
the macroscopic realm of ordinary-sized objects 1macro = large2 and the submicroscopic realm of atoms and molecules
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They make new types of matter
materials, substances, or combinations of substances with desired properties
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Water, for example, is a compound composed of two elements
hydrogen and oxygen
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We can also use a significant chemical difference between these metals
Gold resists most acids
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We define work, w, as the product of the force exerted on the object, F,is defined as any push or pull exerted on the object and the distance, d, that it moves
w = Fxd
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The magnitude of kinetic energy, Ek, of an object depends on its mass, m, and velocity, v
Ek = 1/2 mv^2
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It has since been defined in terms of a joule
1 cal = 4.184 J (exactly)
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A related energy unit that is familiar to anyone who has read a food label is the nutritional Calorie (note the capital C), which is 1000 times larger than calorie with a lowercase c
1 Cal = 1000 cal = 1 kcal
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Two kinds of numbers are encountered in scientific work
exact numbers (those whose values are known exactly) and inexact numbers (those whose values have some uncertainty)
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