Chemistry: matter and change – Flashcards
Unlock all answers in this set
Unlock answersquestion
Applied Research
answer
research that is directed toward a practical goal or application, research undertaken to solve a specific problem
question
Chemistry
answer
The scientific study of matter and the changes it undergoes
question
Conclusion
answer
a judgment based on the information obtained
question
Control
answer
In an experiment, the standard used for comparison.
question
Dependent Variable
answer
in an experiment, the variable whose value depends on the independent variable
question
Experiment
answer
a set of controlled observations that test the hypothesis
question
Hypothesis
answer
a tentative, testable statement or prediction about what has been observed
question
Independent Variable
answer
in an experiment, the variable that the experimenter plans to change
question
Mass
answer
a measure of the amount of matter
question
Matter
answer
anything that has mass and takes up space
question
Model
answer
a visual, verbal, and/or mathematical explanation of data collected from many experiments
question
Pure Research
answer
a type of scientific investigation that seeks to gain knowledge for the sake of knowledge itself
question
Qualitative Data
answer
information describing color, odor, shape, or some other physical characteristic
question
Quantitative Data
answer
numerical information describing how much, how little, how big, how tall, how fast, etc.
question
Scientific Law
answer
describes a relationship in nature that is supported by many experiments
question
Scientific Method
answer
a systematic approach used in scientific study that typically includes observation, a hypothesis, experiments, data analysis, and a conclusion
question
Technology
answer
the practical use of scientific information
question
Theory
answer
an explanation supported by many experiments; still subject to new data and can be modified
question
Weight
answer
a measure of the amount of matter and also the effect of Earth's gravitational pull on the matter
question
accuracy
answer
refers to how close a measured value is to an accepted value
question
base unit
answer
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
question
conversion factor
answer
a ratio of equivalent values used to express the same quantity in different units
question
density
answer
a ratio that compares the mass of an object to its volume
question
derived unit
answer
a unit defined by a combination of base unit
question
dimensional analysis
answer
a problem solving method that focuses on the units that are used to describe matter
question
graph
answer
a visual representation of information that can reveal patterns in data
question
kelvin
answer
the SI base unit of temperature
question
kilogram
answer
the SI base unit for mass
question
liter
answer
the metric unit for volume equal to one cubic decimeter
question
meter
answer
the SI base unit for length
question
percent error
answer
the ratio of an error to an accepted value
question
precision
answer
refers to how close a series of measurements are to one another
question
scientific notation
answer
expresses numbers as a multiple of two factors - a number between 1 and 10, and 10 raised to a power or exponent
question
second
answer
the SI base unit for time
question
significant figure
answer
the number of all known digits reported in measurements plus one estimated digit
question
chemical change
answer
a process involving one or more substances changing into new substances
question
chemical property
answer
the ability or inability of a substance to combine with or change into one or more new substances
question
compound
answer
a chemical combination of two or more different elements
question
element
answer
a pure substance that cannot be broken down into simpler substances
question
gas
answer
a form of matter that flows to conform to the shape of its container, fills the container's volume, and is easily compressed
question
heterogeneous mixture
answer
one that does not have a uniform composition and in which the individual substances remain distinct
question
homogeneous mixture
answer
one that has a uniform composition throughout and always has a single phase
question
law of conservation of mass
answer
states that mass is neither created nor destroyed during a chemical reaction but is conserved
question
law of definite proportions
answer
states that, regardless of the amount, a compound is always composed of the same elements in the same proportion by mass
question
liquid
answer
a form of matter that flows, has constant volume, and takes the shape of its container
question
mixture
answer
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
question
percent by mass
answer
a percentage determined by the ratio of the mass of each element to the total mass of the compound
question
periodic table
answer
a chart that organizes all known elements into a grid of horizontal rows (periods) and vertical columns (groups) arranged by increasing atomic number
question
physical change
answer
a type of change that alters the physical properties of a substance but does not change its composition
question
physical property
answer
a characteristic of matter that can be observed or measured without changing the sample's composition
question
solid
answer
a form of matter that has its own definite shape and volume, is incompressible, and expands only slightly when heated
question
solution
answer
a uniform mixture that may contain solids, liquids, or gases
question
states of matter
answer
the physical forms in which all matter naturally exists on Earth - most commonly solid, liquid, and gas
question
substance
answer
a form of matter that has a uniform and unchanging composition
question
vapor
answer
gaseous state of a substance that is a liquid or a solid at room temperature
question
amplitude
answer
the height of a wave from the origin to a crest
question
atomic emission spectrum
answer
the frequencies of light emitted by an element separated into discrete lines
question
atomic orbital
answer
a 3D region around the nucleus of an atom that describes an electron's probable location
question
aufbau principal
answer
states that each electron occupies the lowest energy orbital available
question
electromagnetic radiation
answer
a form of energy that exhibits wavelike behavior as it travels through space
question
electromagnetic spectrum
answer
includes all forms of electromagnetic radiation, with the only differences in the types of radiation being their frequencies and wavelengths
question
electron configuration
answer
the arrangement of electrons in an atom
question
electron-dot structure
answer
consists of an element's symbol (representing the nucleus & inner electrons) that is surrounded by dots representing the atom's valence electrons
question
energy sublevel
answer
the energy levels contained within a principle energy level.
question
frequency
answer
the number of waves that pass a given point per second
question
ground state
answer
the lowest allowable energy state of an atom
question
Heisenberg uncertainty principle
answer
states that it is not possible to know precisely both the velocity and the position of a particle at the same time
question
Hund's rule
answer
single electrons with the same spin must occupy each orbital before additional electrons with opposite spins can occupy the same orbital
question
Pauli exclusion principle
answer
states that a maximum of two electrons may occupy the same orbital, but only if the electrons have opposite spins
question
photoelectric effect
answer
the emission of electrons from a metal when light shines on the metal
question
photon
answer
a particle of electromagnetic radiation with no mass that carries a quantum of energy
question
Planck's constant
answer
h, which has a value of 6.6261x10^-34 Js, where J is the symbol for Joules
question
principal energy levels
answer
the major energy levels of an atom
question
principal quantum number
answer
n, which in the quantum mechanical model indicates the relative sizes and energies of atomic orbitals
question
quantum
answer
the minimum amount of energy that can be gained or lost by an atom
question
quantum mechanical model of the atom
answer
an atomic model in which electrons are treated as waves
question
valence electron
answer
the electrons in an atom's outermost orbitals
question
wavelength
answer
the shortest distance between equivalent points on a continuous wave
question
alkali metal
answer
group 1A elements, except hydrogen, that are on the left side of the modern periodic table
question
alkaline earth metal
answer
group 2A elements in the modern periodic table
question
electronegativity
answer
ability of an atom to attract electrons when the atom is in a compound
question
group
answer
a vertical column of elements in the periodic table; also called a family
question
halogen
answer
a highly reactive group 7A element
question
inner transition metal
answer
a type of group B element that is contained in the f-block of the periodic table
question
ion
answer
an atom or bonded group of atoms with a positive or negative charge
question
ionization energy
answer
energy required to remove an electron from an atom
question
metal
answer
an element that is a solid at room temperature, a good conductor of heat and electricity, and generally shiny
question
metalloid
answer
an element, such as silicon or germanium, that has physical and chemical properties of both metals and nonmetals
question
noble gas
answer
an extremely unreactive group 8A element
question
nonmetal
answer
elements that are generally gases or dull, brittle solids that are poor conductors of heat and electricity
question
period
answer
a horizontal row of elements in the modern periodic table
question
periodic law
answer
states that when the elements are arranged by increasing atomic number, there is periodic repetition of their chemical and physical properties
question
representative elements
answer
groups of elements in the modern periodic table that are designated with an A (1A through 8A) and possess a wide range of chemical and physical properties
question
transition metal
answer
a type of group B element that is contained in the d-block of the periodic table
question
transition elements
answer
groups of elements in the modern periodic table that are designated with a B(1B through 8B) and are further divided into transition metals and inner transition metals
question
cation
answer
positive ion; formed by metallic elements
question
anion
answer
negative ion; mostly formed by nonmetal elements
question
covalent bond
answer
a bond that results from the sharing of valence electrons
question
endothermic
answer
chemical reaction in which a greater amount of energy is required to break the existing bonds in reactants than is released when the new bonds form in product molecules
question
exothermic
answer
a chemical reaction in which more energy is released that is required to break bonds in the initial reaction
question
Lewis structure
answer
a model that uses electron-dot structures to show how electrons are arranged in molecules
question
molecule
answer
forms when two or more atoms covalently bond; usually includes two or more nonmetals
question
polar covalent
answer
a type of bond that forms when electrons are not shared equally
question
structural formula
answer
a molecular model that uses symbols and bonds to show relative positions of atoms
question
VSEPR model
answer
model based on an arrangement that minimizes the repulsion of shared and unshared pairs of electrons around the central atom
question
alloy
answer
a mixture of elements that has metallic properties
question
chemical bond
answer
the force that holds two atoms together
question
delocalized electrons
answer
the electrons involved in metallic bonding that are free to move easily from one atom to the next throughout the metal and are not attached to a particular atom
question
formula unit
answer
the simplest ratio of ions represented in an ionic compound
question
ionic bond
answer
the electrostatic force that holds oppositely charged particles together; usually a nonmetal paired with a metal
question
metallic bond
answer
the attraction of a metallic cation for delocalized electrons
question
monatomic ion
answer
ion formed from only one atom
question
oxidation number
answer
the positive or negative charge of a monatomic ion
question
polyatomic ion
answer
an ion made up of two or more atoms bonded together that acts as a single unit with a net charge
question
aqueous solution
answer
a solution in which the solvent is water
question
chemical equation
answer
a statement using chemical formulas to describe the identities and relative amounts of the reactants and products involved in the chemical reaction
question
chemical reaction
answer
the process by which the atoms of one or more substances are rearranged to form different substances
question
coefficient
answer
the number written in front of a reactant or product in a chemical equation
question
combustion reaction
answer
a chemical reaction that occurs when a substance reacts with oxygen, releasing energy in the form of heat and light
question
decomposition reaction
answer
a chemical reaction that occurs when a single compound breaks down into two or more elements
question
double replacement reaction
answer
a chemical reaction that involves the exchange of positive ions between two compounds and produces either a precipitate, a gas, or water
question
precipitate
answer
a solid produced during a chemical reaction in a solution
question
product
answer
a substance formed during a chemical reaction
question
reactant
answer
the starting substance in a chemical reaction
question
single replacement reaction
answer
a chemical reaction that occurs when the atoms of one element replace the atoms of another element in a compound
question
solute
answer
a substance dissolved in a solution
question
solvent
answer
the substance that dissolves a solute to form a solution
question
synthesis reaction
answer
a chemical reaction in which two or more substances react to yield a single product
question
Avagadro's number
answer
6.02 x 10^23, which represents the number of particles in a mole
question
empirical formula
answer
a formula that shows the smallest whole number mole ratio of the elements of a compound and may/may not be the same as the actual molecular formula
question
hydrate
answer
a compound that has a specific number of water molecules bound to its atoms
question
molar mass
answer
the mass in grams of one mole of any pure substance
question
mole
answer
the SI unit used to measure the amount of a substance
question
molecular formula
answer
a formula that specifies the actual number of atoms of each element in one molecule or formula unit of a substance
question
percent composition
answer
the percent by mass of each element in a compound
question
Avogadro's principle
answer
if temperature and pressure are constant, gases with the same volume will then have the same number of particles
question
Boyle's law
answer
if temperature is constant, volume and pressure are inversely proportional
question
Charles's law
answer
if pressure is constant, volume and temperature are directly proportional
question
combined gas law
answer
combines Boyle's, Charles's, and Gay-Lussac's law to show the relationship between pressure, volume, and temperature for a fixed amount of gas
question
Gay-Lussac's law
answer
if volume is constant, pressure and temperature are directly proportional
question
ideal gas constant
answer
an experimentally determined constant whose value in the ideal gas equation depends on the units that are used for pressure
question
ideal gas law
answer
describes the behavior of an ideal gas in terms of temperature, volume, and pressure, and number of moles of gas present
question
molar volume
answer
the volume that gas occupies at zero degrees Celsius and 1.0 atmospheres (STP); 22.4L
question
calorie
answer
the amount of heat required to raise the temperature of one gram of pure water by one degree Celsius
question
calorimeter
answer
an insulated device that is used to measure the amount of heat released or absorbed during a physical or chemical process
question
chemical potential energy
answer
energy stored in a substance because of its composition
question
energy
answer
the capacity to do work or produce heat
question
enthalpy
answer
the heat content of a system at constant pressure
question
entropy
answer
a measure of disorder or randomness of the particles of a system
question
free energy
answer
energy available to do work
question
heat
answer
a form of energy that flows from a warmer object to a cooler object
question
Hess's law
answer
two or more thermochemical equations can be added to produce a final equation for a reaction
question
joule
answer
the SI unit for heat
question
law of conservation of energy
answer
energy may change from one form or another, but is neither created nor destroyed
question
law of disorder
answer
entropy of the universe must increase as a result of a spontaneous reaction
question
heat of fusion
answer
the amount of heat required to melt one mole of a solid substance
question
heat of vaporization
answer
the amount of heat required to evaporate one mole of a liquid
question
specific heat
answer
amount of heat required to raise the temperature of one gram of a given substance by one degree Celsius
question
surrounding
answer
includes everything in the universe except the system
question
system
answer
the specific part of the universe containing the reaction or the process being studied
question
thermochemical equation
answer
a balanced chemical equation that includes the physical states of all the reactants and products and specifies the change in enthalpy
question
thermochemistry
answer
the study of heat changes that accompany chemical reactions and phase changes
question
universe
answer
the system plus the surrounding
question
activation energy
answer
the minimum amount of energy required to start a chemical reaction
question
catalyst
answer
a substance that initiates or accelerates a chemical reaction without itself being affected
question
collision theory
answer
states that chemical reactions occur through collisions between molecules or atoms
question
complex reaction
answer
A chemical reaction that consists of two or more elementary steps.
question
instantaneous rate
answer
The rate of decomposition at a specific time, calculated from the rate law, the specific rate constant, and the concentrations of all the reactants.
question
intermediate
answer
A substance formed in one elementary step of a complex reaction and consumed in another
question
rate-determining step
answer
the slowest elementary step in a complex reaction
question
rate law
answer
an equation that relates reaction rate and concentrations of reactants
question
reaction mechanism
answer
a series of elementary reactions that take place during the course of a complex reaction
question
reaction order
answer
defines how rate is affected by concentration of that reactant
question
reaction rate
answer
the change in concentration of reactants or products per unit time as a reaction proceeds
question
concentration
answer
describes how much solute is present in a solution compared to the amount of solvent
question
molality
answer
the concentration of a solution expressed in moles of solute per kilogram of solvent
question
molarity
answer
concentration measured by the number of moles of solute per liter of solvent
question
solubility
answer
the maximum amount of solute that will dissolve in a given amount of time at a specific temperature and pressure
question
soluble
answer
capable of being dissolved in a given substance
question
saturated solution
answer
contains the maximum amount of dissolved solute for a given amount of solvent at a specific temperature and pressure
question
unsaturated solution
answer
a solution that contains less solute than a saturated solution does and that is able to dissolve additional solute
question
supersaturated solution
answer
contains more dissolved solute than a saturated solution at the same temperature
question
solute
answer
the dissolved substance in a solution
question
solvent
answer
a liquid substance capable of dissolving other substances
question
chemical equilibrium
answer
a chemical reaction and its reverse proceed at equal rates
question
equilibrium constant
answer
describes the ratio of product concentrations to reactant concentrations raised to the power indicated by the coefficients
question
Le Chatelier's Principle
answer
a change in any of the factors determining equlibrium will cause the system to adjust to reduce the effect of the change
question
reversible reaction
answer
A chemical reaction in which the products re-form the original reactants
question
acidic solution
answer
a solution whose pH is less than 7
question
Arrhenius model
answer
An acid is a substance that contains hydrogen and ionizes to produce hydrogen ions in aqueous solution; A base is a substance that contains a hydroxide group and dissociates to produce a hydroxide ion in aqueous solution
question
basic solution
answer
a solution whose pH is greater than 7
question
Bronsted-Lowry model
answer
a model of acids and bases in which an acid is a hydrogen ion donor and a base is a hydrogen ion acceptor
question
buffer
answer
an ionic compound that resists changes in its pH
question
conjugate acid
answer
the particle formed when a base gains a hydrogen ion
question
conjugate base
answer
the particle that remains when an acid has donated a hydrogen ion
question
neutralization reaction
answer
the reaction of an acid and a base to form a neutral solution of water and a salt
question
pH
answer
the negative logarithm of the hydrogen ion concentration of a solution
question
pOH
answer
the negative logarithm of the hydroxide ion concentration of a solution
question
strong acid
answer
an acid that ionizes completely in aqueous solution
question
strong base
answer
A base that dissociates completely into ions in solution.
question
titration
answer
process in which a solution of known concentration is used to determine the concentration of another solution
question
weak acid
answer
an acid that is only slightly ionized in aqueous solution
question
weak base
answer
A base that does not dissociate completely into ions in solution.
