193 terms

NY Regents Chemistry Vocabulary

NYS Regents Chemistry Vocabulary set based on work by Mr Guch, www,chemfiesta.com
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absolute temperature
This is a temperature reading made relative to absolute zero. We use the unit of Kelvins for these readings.
absolute zero
This is the lowest temperature possible. If you remember that temperature is a measurement of how much atoms move around in a solid, you can guess that they stop moving entirely at absolute zero. In reality, bonds still vibrate a little bit, but for t
accuracy
When you measure something, the accuracy is how close your measured value is to the real value. For example, if you're actually six feet tall and your brother measures your height as six feet, one inch, he's pretty accurate. However, if your cousin me
acid
This is anything that gives off H+ ions in water. Acids have a pH less than 7 and are good at dissolving metals. They turn litmus paper red and phenolphthalein colorless.
activated complex
In a chemical reaction, the reagents have to join together into a great big blob before they can fall back apart into the products. This great big blob is called the activated complex (a.k.a. transition state)
activation energy
The minimum amount of energy needed for a chemical reaction to take place. For some reactions this is very small (it only takes a spark to make gasoline burn). For others, it's very high (when you burn magnesium, you need to hold it over a Bunsen burn
activity series
This is when you arrange elements in the order of how much they tend to react with water and acids.
alcohol
An organic molecule containing an -OH group
aldehyde
An organic molecule containing a -COH group
alkali metals
Group I in the periodic table.
alkaline earth metals
Group II in the periodic table.
alkane
An organic molecule which contains only single carbon-carbon bonds.
alkene
An organic molecule containing at least one C=C bond
alkyne
An organic molecule containing at least one C-C triple bond.
allotropes
When you have different forms of an element in the same state. The relationship that white phosphorus and red phosphorus have to each other is that they're allotropes.
alloy
A mixture of two metals. Usually, you add very small amounts of a different element to make the metal stronger and harder.
alpha particle
A radioactive particle equivalent to a helium nucleus (2 protons, 2 neutrons)
amine
An organic molecule which consists of an ammonia molecule where one or more of the hydrogen atoms has been replaced by organic groups.
amino acid
The basic building blocks of proteins. They're called "amino acids" because they're both amines (they contain nitrogen) and acids (carboxylic acids, to be precise)
anode
The electrode where oxidation occurs. In other words, this is where electrons are lost by a substance.
aqueous
dissolved in water
atomic mass unit (a.m.u.)
This is the smallest unit of mass we use in chemistry, and is equivalent to 1/12 the mass of carbon-12. To all intents and purposes, protons and neutrons weigh 1 a.m.u.
atomic radius
This is one half the distance between two bonded nuclei. Why don't we just measure the distance from the nucleus to the outside of the atom - after all, isn't that the same thing as a radius? It is, but atoms are also (theoretically) infinitely large
Avogadro's Law
If you've got two gases under the same conditions of temperature, pressure, and volume, they've got the same number of particles (atoms or molecules). This law only works for ideal gases, none of which actually exist.
base
A compound that gives off OH- ions in water. They are slippery and bitter and have a pH greater than 7.
battery
This is when a bunch of voltaic cells are stuck together.
beta particle
A radioactive particle equivalent to an electron.
binary compound
A compound only having two elements
bond energy
The amount of energy it takes to break one mole of bonds.
bond length
The average distance between the nuclei of two bonded atoms.
Boyle's Law
The volume of a gas at constant temperature varies inversely with pressure. In other words, if you put big pressure on something, it gets small.
Bronsted-Lowry acid
Acids donate protons [H+ ions] and bases grab them
calorimetry
The study of heat flow. Usually you'd do calorimetry to find the heat of combustion of a compound or the heat of reaction of two compounds.
carboxylic acid
An organic molecule with a -COOH group on it. Acetic acid is the most famous one.
organic acid
An organic molecule with a -COOH group on it. Acetic acid is the most famous one.
catalyst
A substance that speeds up a chemical reaction without being used up by the reaction. Enzymes are catalysts because they allow the reactions that take place in the body to occur fast enough that we can live.
cathode
The electrode in which reduction occurs. Reduction is when a compound gains electrons.
chain reaction
A reaction in which the products from one step provide the reagents for the next one. This is frequently referred to in nuclear fission (when large nuclei break apart to form smaller ones) and in free-radical reactions.
Charles's Law
The volume of a gas at constant pressure is directly proportional to the temperature. In other words, if you heat something up, it gets big.
chemical equation
The recipe that describes what you need to do to make a reaction take place.
chemical properties
Properties that can only be described by making a chemical change (by making or breaking bonds). For example, color isn't a chemical property because you don't need to change something chemically to see what color it is. Flammability, on the other han
chromatography
This is when you use a system containing a mobile phase (usually a liquid in general chemistry classes) and a stationary phase (something dissolved in the liquid) to separate different compounds. This is usually done by exploiting the differing polarit
circuit
The closed path in a circuit through which electrons flow.
coagulation
When you destroy a colloid by letting the particles settle out.
colligative property
Any property of a solution that changes when the concentration changes. Examples are color, flavor, boiling point, melting point, and osmotic pressure.
colloid
It's a suspension.
combustion
When a compound combines with oxygen gas to form water, heat, and carbon dioxide
conjugate acid
The compound formed when a base gains a proton (hydrogen atom).
conjugate base
The compound formed when an acid loses a proton (hydrogen atom).
covalent bond
A chemical bond formed when two atoms share two electrons.
crystal lattice
see "lattice"
crystal
A large chunk of an ionic solid.
decomposition
When a big molecule falls apart to make two or more little ones.
dipole moment
When a molecule has some charge separation (usually because the molecule is polar), it's said to have a dipole moment.
dipole-dipole force
When the positive end of a polar molecule becomes attracted to the negative end of another polar molecule.
distillation
This is when you separate a mixture of liquids by heating it up. The one with the lowest boiling point evaporates first, followed by the one with the next lowest boiling point, etc.
electrolyte
An ionic compound that dissolves in water to conduct electricity. Strong electrolytes break apart completely in water; weak electrolytes only fall apart a little bit.
electron affinity
The energy change that accompanies the addition of an electron to an atom in the gas phase.
electronegativity
A measurement of how much an atom tends to steal electrons from atoms that it's bonded to. Elements at the top right of the periodic table (excluding the noble gases) are very electronegative while atoms in the bottom left are not very electronegative
electropositive
When something is not at all electronegative. In fact, it tends to lose electrons rather than to gain them. Elements that are electropositive are generally to the left and bottom of the periodic table.
empirical formula
A reduced molecular formula. If you have a molecular formula and you can reduce all of the subscripts by some constant number, the result is the empirical formula.
emulsion
When very small drops of a liquid are suspended in another. An example of an emulsion is salad dressing after you've shaken it up.
endothermic
When a process absorbs energy (gets cold).
endpoint
The point where you actually stop a titration, usually because an indicator has changed color. This is different than the "equivalence point" because the indicator might not change colors at the exact instant that the solution is neutral.
enthalpy
A measurement of the energy content of a system.
entropy
A measurement of the randomness in a system.
enzyme
A biological molecule that catalyzes reactions in living creatures.
equilibrium
When the forward rate of a chemical reaction is the same as the reverse rate. This only takes place in reversible reactions because these are the only type of reaction in which the forward and backward reactions can both take place.
equivalence point
The point in a titration at which the solution is completely neutral. This is different than the "endpoint" (see above).
ester
An organic molecule with R-CO-OR' functionality.
exothermic
When a process gives off energy (gets hot).
family
The same thing as a "group" (see above)
first law of thermodynamics
The energy of the universe is constant. It's the same thing as the Law of conservation of energy.
fission
A nuclear reaction where a big atom breaks up into little ones. This is what happens in nuclear power plants.
functional group
A generic term for a group of atoms that cause a molecule to react in a specific way. It's really common to talk about this in organic chemistry, where you have "aldehydes, carboxylic acids, amines" and so on.
gamma ray
High energy light given off during a nuclear process. When a nucleus gives off this light, it goes to a lower energy state, making it more stable.
ground state
The lowest energy state possible for an electron.
group
A column (the things up and down) in the periodic table. Elements in the same group tend to have the same properties. These are also called "families".
half-life
The time required for half of the radioactive atoms in a sample to decay. When talking about chemical reactions, it's the amount of time required to make half the reagent react.
half-reaction
The oxidation or reduction part of a redox reaction.
halogen
The elements in group 17. They're really reactive.
heat of reaction
The amount of heat absorbed or released in a reaction. Also called the "enthalpy of reaction"
heat
The kinetic energy of the particles in a system. The faster the particles move, the higher the heat.
heterogeneous mixture
A mixture where the substances aren't equally distributed.
homogeneous mixture
A mixture that looks really "smooth" because everything is mixed up really well.
hydration
When a molecule has water molecules attached to it.
hydrocarbon
A molecule containing carbon and hydrogen.
hydrogen bond
The tendency of the hydrogen atom stuck to an electronegative atom to become attracted to the lone pair electrons on another electronegative atom. It's a pretty strong intermolecular force, which explains why water has such a high melting and boiling p
hydrogenation
When hydrogen is added to a carbon-carbon multiple bond.
hydronium ion
The H+ ion, made famous by acids.
hydroxide ion
The OH- ion, made famous by bases.
ideal gas
A gas in which the particles are infinitely small, have a kinetic energy directly proportional to the temperature, travel in random straight lines, and don't attract or repel each other. Needless to say, there's no such thing as an ideal gas in the rea
immiscible
When two substances don't dissolve in each other. Think of oil and water. They're immiscible. Organic compounds and water are frequently immiscible.
indicator
A compound that turns different colors at different pH values. We generally like to have the color change at a pH of around seven because that's where the equivalence point of a titration is.
inhibitor
A substance that slows down a chemical reaction.
inorganic compound
Any compound that doesn't contain carbon (except for carbon dioxide, carbon monoxide, and carbonates).
insoluble
When something doesn't dissolve.
intermolecular force
A force that exists between two different molecules. Examples are hydrogen bonding (which is strong), dipole-dipole forces (which are kind of weak), and London dispersion forces (a.k.a. Van der Waal forces), which are very weak.
ionic bond
A bond formed when charge particles stick together.
ionization energy
The amount of energy required to pull an electron off of a gaseous atom.
isotope
When an element has more than one possibility for the number of neutrons, these are called isotopes. All known elements posess isotopes. For the record, the word "isotope" doesn't imply that something is radioactive. TV told you that, and TV is stupi
Kelvin
A unit used to measure temperature. One Kelvin is equal in size to one degree Celsius. To convert between degrees Celsius and Kelvins, simply add 273.15 to the temperature in degrees Celsius to get Kelvins.
ketone
A molecule containing a R-CO-R' functional group. Acetone (dimethyl ketone) is a common one.
kinetic energy
The energy due to the movement of an object. The more something moves, the more kinetic energy it has.
lattice
The three-dimensional arrangement of atoms or ions in a crystal.
law of conservation of energy
The amount of energy in the universe never changes, ever. It just changes form.
law of conservation of mass
The amount of stuff after a chemical reaction takes place is the same as the amount of stuff you started with.
Le Chatlier's Principle
When you disturb an equilibrium (by adding more chemical, by heating it up, etc.), it will eventually go back into equilibrium under a different set of conditions.
Lewis acid
An electron-pair acceptor (carbonyl groups are really good ones)
Lewis base
An electron-pair donor. Things with lone pairs like water and ammonia are really good ones.
Lewis structure
A structural formula that shows all of the atoms and valence electrons in a molecule.
line spectrum
A spectrum showing only certain wavelengths.
London dispersion force
The forces between nonpolar atoms or molecules which is caused by momentary induced dipoles. It's real weak.
lone pair
two electrons that aren't involved in chemical bonding. Also frequently referred to as an "unshared pair".
main-block elements
Groups 1,2, and 13-18 in the periodic table. They're called main block elements because the outermost electron is in the s- or p- orbitals. What that has to do with the term "main block" is unclear to me, but hey, that's life.
mass defect
The difference between the mass of an atom and the sum of the masses of its individual components. Atoms usually weigh a little less than if you added up the weights of all the particles. This is because that extra mass was converted into the energy w
mass
The amount of matter in an object. The more mass, the more stuff is present.
molality
The number of moles of solute per kilogram of solvent in a solution. This is a unit of concentration that's not anywhere near as handy or common as molarity.
molar mass
The mass of one mole of particles.
molar volume
The volume of one mole of a substance at STP. If you believe that everything is an ideal gas, this is always 22.4 liters. Unfortunately, there's no such thing as an ideal gas.
molarity
A unit of concentration equal to moles of solute divided by liters of solution.
mole fraction
The number of moles of stuff in a mixture that are due to one of the compouds.
mole ratio
The ratio of moles of what you've been given in a reaction to what you want to find. Handy in stoichiometry.
mole
6.02 x 1023 things.
molecular compound
A compound held together by covalent bonds.
molecular formula
A formula that shows the correct quantity of all of the atoms in a molecule.
monatomic ion
An ion that has only one atom, like the chloride ion.
neutralization reaction
The reaction of an acid with a base to form water and a salt.
nonpolar covalent bond
A covalent bond where the electrons are shared equally between the two atoms.
normal boiling point
The boiling point of a substance at 1.00 atm.
normal melting point
The melting point of a substance at 1.00 atm.
nuclar fusion
When many small atoms combine to form a large one. This occurs during a thermonuclear reaction.
nuclear fission
This is when the nucleus of an atom breaks into many parts.
nuclear reaction
Any reaction that involves a change in the nucleus of an atom. Nuclear reactions take loads of energy, which is why you don't see them much around the lab.
nucleon
A particle (such as proton or neutron) that's in the nucleus of an atom.
octet rule
All atoms want to be like the nearest noble gas. (Well, they all want to have the same number of valence electrons, anyway). To do this, they either gain or lose electrons (to form ionic compounds) or share electrons (to form covalent compounds).
orbital
This is where the electrons in an atom live.
organic compound
A compound that contains carbon (except carbon dioxide, carbon monoxide, and carbonates)
oxidation number
The apparent charge on an atom.
oxidation
When a substance loses electrons.
partial pressure
The pressure of one gas in a mixture. For example, if you had a 50
period
A row (left to right) in the periodic table.
periodic law
The properties of elements change with increasing atomic number in a periodic way. That's why you can stick the elements into a big chart and have the elements line up in nice families.
pH
-log[H+]
phase diagram
A chart which shows how the phase depends on various conditions of temperature and pressure.
phase
The state of a compound (solid, liquid, or gas)
physical property
A property which can be determined without changing something chemically. If that doesn't make sense, see the definition of "chemical change".
polar covalent bond
A covalent bond where one atom tries to grab the electrons from the other one. This occurs because the electronegativities of the two atoms aren't the same.
polyatomic
contains more than one atom.
polymer
A molecule containing many repeating units. Plastics are polymers and are formed by free radical chain reactions.
polyprotic acid
An acid that can give up more than one hydronium ion. Examples are sulfuric acid and phosphoric acid.
potential energy
The energy something has because of where it is. Things that are way up high have more potential energy than things that are way down low because they have farther to fall.
precision
A measurement of how repeatable a measurement is. The more significant figures, the more precise the measurement.
pressure
Force/area
product
The thing you make in a chemical reaction.
quantum theory
The branch of physical chemistry that describes how energy can only exist at certain levels and makes generalizations about how atoms behave from this assumption.
radioactive
When a substance has an unstable nucleus that can fall apart, it's referred to as radioactive.
redox reaction
A reaction that has both an oxidation and reduction.
salt
An ionic compound.
saturated
When the maximum amount of solute is dissolved in a liquid
Second law of thermodynamics
Whenever you do something, the universe gets more random.
semiconductor
A substance that conducts electricity poorly at room temperature, but has increasing conductivity at higher temperatures. Metalloids are usually good semiconductors.
shielding effect
The outer electrons aren't pulled very tightly by the nucleus because the inner electrons repel them. This repulsion is called the shielding effect, and can be used to explain lots of neat-o stuff.
significant figure
The number of digits in a number that tell you useful information. For example, when you weigh yourself on a bathroom scale, it says something like 150 pounds rather than 150.32843737 pounds. Why? Because the thing can only weigh accurately to the ne
single-displacement reaction (a.k.a. single replacement reaction)
When one unbonded element replaces an element in a chemical compound. These are frequently redox reactions.
solubility
A measurement of how much of a solute can dissolve in a liquid.
solute
The solid that gets dissolved in a solution.
solvent
The liquid that dissolves the solid in a solution.
specific heat capacity
The amount of heat required to increase the temperature of one gram of a substance by one degree.
standard temperature and pressure
One atmosphere and 273 K.
stoichiometry
The art of figuring how much stuff you'll make in a chemical reaction from the amount of each reagent you start with.
STP
See standard temperature and pressure.
strong acid
An acid that fully dissociates in water
strong nuclear force
The force that holds the nucleus together. As the name suggests, this force is strong.
structural formula
See Lewis structure.
sublimation
When a solid can change directly into a gas. Dry ice does this.
supercooling
When you cool something below its normal freezing point
supersaturated
When more solute is dissolved in a liquid than is theoretically possible. This doesn't happen much, as you might imagine.
surface tension
A measurement of how much the molecules on a liquid tend to like to stick to each other. If something has a high surface tension, it likes to bead up.
suspension
A mixture that looks homogeneous when you stir it, but where the solids settle out when you stop. Mud is a very short-lived suspension, while peanut butter is a very long-lived suspension.
synthesis
When you make a big molecule from two or more smaller ones.
system
Everything you're talking about at the moment.
temperature
A measurement of the average kinetic energy of the particles in a system.
thermodynamics
The study of energy
titration
When the concentration of an acid or base is determined by neutralizing it.
transition state
See "activated complex"
unsaturated
When you haven't yet dissolved all of the solute that's possible to dissolve in a liquid.
unshared electron pair
two electrons that aren't involved in chemical bonding. Also frequently referred to as a "lone pair".
valence electron
The outermost electrons in an atom.
vapor pressure
The pressure of a substance that's present above it's liquid. For example, you can tell that ammonia has a high vapor pressure because the smell of it is very strong above liquid ammonia.
vaporization
When you boil a liquid.
volatile
A substance with a high vapor pressure.
VSEPR
A theory for predicting molecular shapes that assumes that electrons like to be as far from each other as possible.
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