mole correct answers the unit for the amount of a substance; the amount of atoms in exactly 12
grams of carbon-12
(abbreviated mol)
Avogadro's constant correct answers 6.02 * 10^23
relative atomic mass (Ar) correct answers the weighted average mass of all naturally occurring
isotopes of an element relative to 1/12th of the mass of a C-12 atom
relative molecular mass (Mr) correct answers the sum of the Ar for all the constituent atoms in a
molecule
molar mass (M) correct answers the mass of one mole of a substance. It is defined as: m/n where
m is the mass of the sample, in g, over n which is the number of moles. The unit of molar mass is
g/mol
empirical formula correct answers the simplest whole number ratio of atoms of each element in a
compound
molecular formula correct answers the actual number of atoms of each element in a compound
chemical equation correct answers Shows the rearrangement of atoms within an isolated system
where the overall mass does not change. (Ex: AB + CD --> AC + BD.) Both conservation of
mass and conservation of charge principles must be obeyed in a chemical reaction. Reactants
appear on the left side of the equation and products on the right side.
,coefficients correct answers Indicate the relative quantities of reactants required for the reaction.
They indicate how many moles of a substance are involved in the reaction.
subscripts correct answers indicate how many particles there are in one unit of a substance
salt correct answers neutral ionic compounds of cations (positively charged ions) and anions
(negatively charged ions)
limiting reactant correct answers The reactant that is used up first. It limits the amount of product
formed. Once the limiting reactant runs out the maximum yield of product is reached. This can
be found by comparing what you have by what you need based of off coefficients.
theoretical yield correct answers the amount of product, in grams or moles, predicted from the
limiting reactant
experimental yield correct answers The amount of product, in grams or moles, obtained from
experiment. (Note: the experimental yield is never greater than the theoretical yield.)
percentage yield correct answers % = (expected / theoretical)*100
ideal gas equation correct answers The equation governing the volume, pressure, and
temperature behavior of an ideal gas: PV = nRT. In which:
P= pressure (kPa)
V= volume (dm^3)
T= temperature (K)
n= amount (mol)
R= gas constant (8.314 J/K/mol)
,Avogadro's Law correct answers Two containers with equal volumes of different gases at the
same temperature (T) and pressure (P) contain the same number of gas particles. (PaVa/RTa =
PbVb/RTb). It is particularly useful when all reactants and products are gases.
molar volume of an ideal gas correct answers the volume of 1 mole of any ideal gas at 273 K and
101.3 kPa is 22.4 dm^3 (22.4=[8.31*273]/101.3)
solution correct answers the mixture of the solute and solvent (NaCl dissolved in water)
solute correct answers solid, liquid, or gas that is dissolved in the solvent (NaCl)
solvent correct answers the component that is present in excess in which the solute dissolves
(water)
concentration correct answers The concentration of solute in a solvent is the amount of substance
(n, in mol) divided by the volume of solution (V, in dm^3). The units of concentration are
typically mol/dm^3. (c mol/dm^3= n mol/V dm^3)
nuclear model correct answers a model of that atom that features a small, dense, positively
charged nucleus containing all protons and neutrons in the center of the atom, surrounded by the
electrons
charge and relative mass of proton, neutrons, and electrons correct answers proton: +1; 1
neutron: 0; 1
electron: -1; 1/1840
atomic number (Z) correct answers the number of protons in the nucleus of an atom
mass number (A) correct answers the sum of the masses of all protons and neutrons in an atom
, isotopes of an element correct answers Forms of an element that have a different number of
neutrons, and therefore different mass. All isotopes of an element possess the same number of
protons.
uses of isotopes correct answers 1. Iodine-125: used in prostate and brain cancer therapy
2. Iodine-131: treats thyroid cancer in imaging the thyroid (also causes thyroid cancer in areas
with high radioactivity; can be prevented by using iodine-127 in the form KI)
3. Cobalt-60: used for external beam radiotherapy for treating many types of cancer
4. Carbon-14: used in radiocarbon dating which determines the age of carbon-containing remains
by looking at its half-life and mass
mass spectrometer correct answers an instrument that separates particles according to their
masses and charges and records the relative proportions of these
operation of the mass spectrometer correct answers 1. Vaporization: converts the substance to gas
via heat
2. Ionization: the gaseous particles are bombarded with high energy electrons that knock off
electrons to form positive ions
3. Acceleration: particles accelerate via a potential differences between two parallel plates
4. Deflection: the particles are deflected in a magnetic field
5. Detection: the charge particles are collected in a detector, generating an electric signal which
is determined by the quantity of charged particles
[Note: Lighter particles/higher charged particles leave the chamber sooner than heavier
particles/lower charged particles due to the magnetic force]
electromagnetic radiation correct answers an energy form, with wave-like behavior, that travels
through a vacuum at the speed of light
wavelength correct answers the distance between two crests of an oscillating wave, typically in
unites of nanometers