HESI-A2 CHEMISTRY
Chemistry note cards for HESI entrance exam
QuestionAnswer
Matter that has a definite shape and volume solid
Matter that changes in
... [Show More] volume with changes in
temperature and pressure gas
A change of matter is when no
change is made to the chemical composition of a
substance.
physical
Simplest of substances and is represented by a
letter or letters element
Law that states matter can neither be created nor
destroyed during a chemical reaction Law of conservation of mass
The breaking of bonds and reforming of new
bonds to create new chemical compounds with
different chemical formulas and different chemical
properties
Chemical reaction
5 main chemical reactions synthesis, decomposition, combustion,
single replacement, double replacement
Chemical reaction in which 2 elements combine to
form a product synthesis
Chemical reaction that is the breaking of a
compound into component parts decomposition
The chemical reaction that is the reaction of a
compound with oxygen combustion
Chemical reaction that consists of an active metal
reaction with an ionic compound creating a new
compound
single replacement
Chemical reaction involving 2 ionic compounds;
the reactant yields "switched partners" double replacement
how elements are arranged on the periodic table by their chemical properties
Number that represents the # of protons an atomic number
element has
average of the masses of each of its isotopes as
they occur in nature atomic mass
Mass number - atomic number = # of neutrons in an element
Columns of the periodic table = groups
Rows of the periodic table = periods
Group IA = charge +1
Group IIA = charge +2
Group IIIA = charge +3
Group VA = charge -3
Group VIA = charge -2
Group VIIA = charge -1
Charge of noble gases 0
Positively charged ions protons
Negatively charged ions electrons
Neutral ions neutrons
# of proteins in an element = atomic number
proteins + neutrons = mass number
In reactions, atoms try to reach stable
electron configurations. chemical
reactions take place in the nucleus,
to obtain stable nuclear configurations. nuclear
Word used to describe the emission of particles
from an unstable nucleus. radioactivity
The particles that are emitted during radioactivity radiation
3 types of radiation alpha, beta, gamma
Radiation that is the emission of helium ions alpha
Alpha radiation particles have a charge of +2 [Show Less]