Chemistry Midterm Review Flashcards
(120 cards)
1
Q
What is a chemical?
A
Any substance that has a defined composition.
2
Q
What is a chemical reaction?
A
The process by which one or more substances change to produce one or more different substances.
3
Q
What are the states of matter?
A
The physical forms of matter; which are solid, liquid, gas, and plasma.
4
Q
What is a reactant?
A
A substance or molecule that participates in a chemical reaction.
5
Q
What is a product?
A
A substance that forms in a chemical reaction.
6
Q
What is matter?
A
Anything that has mass and takes up space.
7
Q
What is volume?
A
A measure of the size of a body or region in three-dimensional space.
8
Q
What is mass?
A
A measure of the amount of matter in an object; a fundamental property of an object that is not affected by the forces that act on the object, such as the gravitational force.
9
Q
What is weight?
A
A measure of the gravitational force exerted on an object; its value can change with the location of the object in the universe.
10
Q
What is quantity?
A
Something that has magnitude, size, or amount.
11
Q
What is a unit?
A
A quantity adopted as a standard of measurement.
12
Q
What is a conversion factor?
A
A ratio that is derived from the equality of two different units and that can be used to convert from one unit to the other.
13
Q
What is a physical property?
A
A characteristic of a substance that does not involve a chemical change, such as density, color, or hardness.
14
Q
What is density?
A
The ratio of the mass of a substance to the volume of the substance; often expressed as grams per cubic centimeter for solids and liquids and as grams per liter for gases.
15
Q
What is a chemical property?
A
A property of matter that describes a substance’s ability to participate in chemical reactions.
16
Q
What is an atom?
A
The smallest unit of an element that maintains the properties of that element.
17
Q
What is a pure substance?
A
A sample of matter, either a single element or a single compound, that has definite chemical and physical properties.
18
Q
What is an element?
A
A substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of an element have the same atomic number.
19
Q
What is a molecule?
A
The smallest unit of a substance that keeps all of the physical and chemical properties of the substance; it can consist of one atom or two or more atoms bonded together.
20
Q
What is a compound?
A
A substance made up of atoms of two or more different elements joined by chemical bonds.
21
Q
What is a mixture?
A
A combination of two or more substances that are not chemically combined.
22
Q
What is a homogeneous mixture?
A
Describes something that has a uniform structure or composition throughout.
23
Q
What is a heterogeneous mixture?
A
Composed of dissimilar components.
24
Q
What is energy?
A
The capacity to do work.
25
What is a physical change?
A change of matter from one form to another without a change in chemical properties.
26
What is a chemical change?
A change that occurs when one or more substances change into entirely new substances with different properties.
27
What is evaporation?
The change of a substance from a liquid to a gas.
28
What is an endothermic process?
Describes a process in which heat is absorbed from the environment.
29
What is an exothermic process?
Describes a process in which a system releases heat into the environment.
30
What is the law of conservation of energy?
The law that states that energy cannot be created or destroyed but can be changed from one form to another.
31
What is heat?
The energy transferred between objects that are at different temperatures; energy is always transferred from higher-temperature objects to lower-temperature objects until thermal equilibrium is reached.
32
What is kinetic energy?
The energy of an object that is due to the object’s motion.
33
What is temperature?
A measure of how hot (or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object.
34
What is specific heat?
The quantity of heat required to raise a unit mass of homogeneous material 1 K or 1 ℃ in a specific way given constant pressure and volume.
35
What is the scientific method?
A series of steps followed to solve problems, including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions.
36
What is a hypothesis?
A theory or explanation that is based on observations and that can be tested.
37
What is a theory?
An explanation for some phenomenon that is based on observation, experimentation, and reasoning.
38
What is a law in science?
A summary of many experimental results and observations; a law tells how things work.
39
What is the law of conservation?
The law that states that mass cannot be created or destroyed in ordinary chemical and physical changes.
40
What is accuracy?
A description of how close a measurement is to the true value of the quantity measured.
41
What is precision?
The exactness of a measurement.
42
What are significant figures?
A prescribed decimal place that determines the amount of rounding off to be done based on the precision of the measurement.
43
What is the law of definite proportions?
The law that states that a chemical compound always contains the same elements in exactly the same proportions by weight or mass.
44
What is the law of conservation of mass?
The law that states that mass cannot be created or destroyed in ordinary chemical and physical changes.
45
What is the law of multiple proportions?
The law that states that when two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers.
46
What is an electron?
A subatomic particle that has a negative electric charge.
47
What is the nucleus of an atom?
An atom’s central region, which is made up of protons and neutrons.
48
What is a proton?
A subatomic particle that has a positive charge and that is found in the nucleus of an atom; the number of protons of the nucleus is the atomic number, which determines the identity of the element.
49
What is a neutron?
A subatomic particle that has no charge and that is found in the nucleus of an atom.
50
What is atomic number?
The number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element.
51
What is mass number?
The sum of the number of protons and neutrons of the nucleus of an atom.
52
What is an isotope?
An atom that has the same number of protons (atomic number) as other atoms of the same element but has a different number of neutrons (atomic mass).
53
What is an orbital?
A region in an atom where there is a high probability of finding electrons.
54
What is the electromagnetic spectrum?
All of the frequencies or wavelengths of electromagnetic radiation.
55
What is the ground state of an atom?
The lowest energy state of a quantized system.
56
What is an excited state?
A state in which an atom has more energy than it does at its ground state.
57
What is the Pauli exclusion principle?
The principle that states that two particles of a certain class cannot be in the exact same energy state.
58
What is electron configuration?
The arrangement of electrons in an atom.
59
What is the Aufbau principle?
The principle that states that the structure of each successive element is obtained by adding one proton to the nucleus of the atom and one electron to the lowest-energy orbital that is available.
60
What is Hund’s rule?
The rule that states that for an atom in the ground state, the number of unpaired electrons is the maximum possible and these unpaired electrons have the same spin.
61
What is atomic mass?
The mass of an atom expressed in atomic mass units.
62
What is a mole?
The SI base unit used to measure the amount of substance whose number of particles is the same as the number of atoms in 12g of carbon-12.
63
What is molar mass?
The mass in grams of 1 mol of a substance.
64
What is Avogadro’s number?
6.02 x 10^23, the number of atoms or molecules in 1 mol.
65
What is the periodic law?
The law that states that the repeating physical and chemical properties of elements change periodically with their atomic number.
66
What is a valence electron?
An electron that is found in the outermost shell of an atom and that determines the atom’s chemical properties.
67
What is a group in the periodic table?
A vertical column of elements in the periodic table; elements in a group share chemical properties.
68
What is a period in the periodic table?
A horizontal row of elements in the periodic table.
69
What are main-group elements?
An element in the s-block or p-block of the periodic table.
70
What are alkali metals?
One of the elements of Group 1 of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium).
71
What are alkaline earth metals?
One of the elements of Group 2 of the periodic table (beryllium, magnesium, calcium, strontium, barium, and radium).
72
What are halogens?
One of the elements of Group 17 of the periodic table (fluorine, chlorine, bromine, iodine, and astatine); halogens combine with most metals to form salts.
73
What are noble gases?
An unreactive element of Group 18 of the periodic table (helium, neon, argon, krypton, xenon, or radon) that has eight electrons in its outer level (except for helium, which has two electrons).
74
What are transition metals?
One of the metals that can use the inner shell before using the outer shell to bond.
75
What are lanthanides?
A member of the rare-earth series of elements, whose atomic number ranges from 58 (cerium) to 71 (lutetium).
76
What are actinides?
Any of the elements of the actinide series, which have atomic numbers from 89 (actinium) through 103 (lawrencium).
77
What are alloys?
A solid or liquid mixture of two or more metals.
78
What is ionization energy?
The energy required to remove an electron from an atom or ion.
79
What is electron shielding?
The reduction of the attractive force between a positively charged nucleus and its outermost electrons due to the cancelation of some of the positive charge by the negative charges of the inner electrons.
80
What is bond radius?
Half the distance from center to center of two like atoms that are bonded together.
81
What is electronegativity?
A measure of the ability of an atom in a chemical compound to attract electrons.
82
What is the octet rule?
A concept of chemical bonding theory that is based on the assumption that atoms tend to have either empty valence shells or full valence shells of eight electrons.
83
What is an ion?
An atom, radical, or molecule that has gained or lost one or more positive charge.
84
What is a cation?
An ion that has a positive charge.
85
What is an anion?
An ion that has a negative charge.
86
What is salt?
An ionic compound that forms when a metal atom or a positive radical replaces the hydrogen of an acid.
87
What is lattice energy?
The energy associated with constructing a crystal lattice relative to the energy of all constituent atoms separated by infinite distances.
88
What is a crystal lattice?
The regular pattern in which a crystal is arranged.
89
What is a unit cell?
The smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire lattice.
90
What is a polyatomic ion?
An ion made of two or more atoms.
91
What is a covalent bond?
A bond formed when atoms share one or more pairs of electrons.
92
What is a molecular orbital?
The region of high probability that is occupied by an individual electron as it travels with a wavelike motion in the three-dimensional space around one of two or more associated nuclei.
93
What is bond length?
The distance between two bonded atoms at their minimum potential energy; the average distance between the nuclei of two bonded atoms.
94
What is bond energy?
The energy required to break the bonds in 1 mol of a chemical compound.
95
What is a nonpolar covalent bond?
A covalent bond in which the bonding electrons are equally attracted to both bonded atoms.
96
What is a polar covalent bond?
A covalent bond in which a shared pair of electrons is held more closely by one of the atoms.
97
What is a dipole?
A molecule or part of a molecule that contains both positively and negatively charged regions.
98
What are Lewis structures?
A structural formula in which electrons are represented by dots; dot pairs or dashes between two atomic symbols represent pairs in covalent bonds.
99
What is an unshared pair?
A nonbonding pair of electrons in the valence shell of an atom; is also called a lone pair.
100
What is a single bond?
A covalent bond in which two atoms share one pair of electrons.
101
What is a double bond?
A covalent bond in which two atoms share two pairs of electrons.
102
What is a triple bond?
A covalent bond in which two atoms share three pairs of electrons.
103
What is a resonance structure?
In chemistry, anyone of two or more possible configurations of the same compound that have identical geometry but different arrangements of electrons.
104
What is VSEPR theory?
A theory that predicts some molecular shapes based on the idea that pairs of valence electrons surrounding an atom repel each other.
105
What is average atomic mass?
The weighted average of the masses of all naturally occurring isotopes of an element.
106
What is percent composition?
The percentage by mass of each element in a compound.
107
What is an empirical formula?
A chemical formula that shows the composition of a compound in terms of the relative numbers and kinds of atoms in the simplest ratio.
108
What is a molecular formula?
A chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms.
109
What is a chemical equation?
A representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products.
110
What is a coefficient in a chemical equation?
A small whole number that appears as a factor in front of a formula in the chemical equation.
111
What is a combustion reaction?
The oxidation reaction of an organic compound, in which heat is released.
112
What is a synthesis reaction?
A reaction in which two or more substances combine to form a new compound.
113
What is a decomposition reaction?
A reaction in which a single compound breaks down to form two or more simpler substances.
114
What is an activity series?
A series of elements that have similar properties and that are arranged in descending order of chemical activity.
115
What is a double-displacement reaction?
A reaction in which gas, a solid precipitate, or molecular compound forms from the apparent exchange of atoms or ions between two compounds.
116
What is a spectator ion?
Ions that are present in a solution in which a reaction is taking place but that do not participate in the reaction.
117
What is stoichiometry?
The proportional relationship between two or more substances during a chemical reaction.
118
What is a limiting reactant?
The substance that controls the quantity of product that can form in a chemical reaction.
119
What is an excess reactant?
The substance that is not used up completely in a reaction.
120
What is actual yield?
The measured amount of a product of a reaction.
