HESI study guide
HESI study guide
1. Chemistry
Metric system prefix mnemonic —King Henry died by drinking chocolate
milk –Kilo, Hecta, Deca, base, deci, centi, mili
Temperature scales—Fahrenheit, Celsius, Kelvin
o Fahrenheit—32F is freezing point for water, 212F is boiling pt. for
water, body temp is 98.6F
o Celsius—0C is freezing point for water, 100C is boiling pt. for water,
body temp is 37C
o Kelvin—0K is -273.15 C and is absolute zero, freezing pt. of water is
273K, boiling pt. of water is 373K, and body temp is 310K
Atomic Structure
o Atom-smallest unit of matter that contains elemental properties
o Structure is the nucleus and orbits, sometimes called the electron
cloud
o In the orbits are the electrons, they spin and form electron clouds
o Protons are positive, neutrons are neutral, and electrons are negative
o Ground state atoms have equal protons and electrons, so they are
neutral
o Ion- an atom that is electrically charged
o Cation- positive—lost electron
o Anion- negative—gained electron
The periodic table
o Families (groups) have common properties
Help determine the amount of valence electrons
Can only be 8 valence electrons at most (octet rule)
There are 18 families
o Periods are the rows
Determines the number of shells
They begin with very reactive alkali metals and ends with an
inert noble gas
Atomic number and atomic mass
o Atomic number is the number of protons in the nucleus and defines
an atom as a particular element
o Atomic mass is the average mass of each of that element’s isotopes
o Isotopes are different kinds of the same atom that vary in weight
, HESI study guide
o Mass – atomic number= # of neutrons
o Atomic number ALWAYS stays the same
o Mass differs because elements can have different #s of neutrons
Chemical equations
o Compounds- two or more elements combined in whole # ratios
(NaCl)
o Chemical equations- recipes for compounds
Reactants- react to produce desired compounds
Products- end result
Reactants products
Law of conservation of mass- mass cannot be created or
destroyed during a chemical reaction.
Equations must be balanced
Reaction rates, equilibrium, and reversibility
o Equilibrium- is a state in which reactants are forming products at the
same rate the products are forming reactants
o Increasing the reaction rate: increasing the temperature, increasing
the surface area, adding a catalyst, or increasing the concentration
o Increasing the temperature increases the kinetic energy and
increases their chances of contact
o Increasing the surface area gives the particles more opportunity to
come into contact with one another
o A catalyst accelerates a reaction by reducing the activation energy or
the amount of energy needed for a reaction to occur. The catalyst is
not used up in the reaction and most common examples are metals
or proteins (enzymes)
Solution and solution concentrations
o Solution- homogenous mixture or two or more substances
o Solute- the part that is being dissolved
o Solvent- the part that is doing the dissolving
o Compounds- chemical species that is formed when two or more
atoms join together chemically, by covalent or ionic bonds
o Alloys- solid solutions of metal to make new metals
o Amalgams- metal is dissolved in mercury
o Emulsion- mixtures of matter that are readily separate (oil and water)
o Concentration is expressed as weight per weight –ml/l, g/g, g/l
HESI study guide
1. Chemistry
Metric system prefix mnemonic —King Henry died by drinking chocolate
milk –Kilo, Hecta, Deca, base, deci, centi, mili
Temperature scales—Fahrenheit, Celsius, Kelvin
o Fahrenheit—32F is freezing point for water, 212F is boiling pt. for
water, body temp is 98.6F
o Celsius—0C is freezing point for water, 100C is boiling pt. for water,
body temp is 37C
o Kelvin—0K is -273.15 C and is absolute zero, freezing pt. of water is
273K, boiling pt. of water is 373K, and body temp is 310K
Atomic Structure
o Atom-smallest unit of matter that contains elemental properties
o Structure is the nucleus and orbits, sometimes called the electron
cloud
o In the orbits are the electrons, they spin and form electron clouds
o Protons are positive, neutrons are neutral, and electrons are negative
o Ground state atoms have equal protons and electrons, so they are
neutral
o Ion- an atom that is electrically charged
o Cation- positive—lost electron
o Anion- negative—gained electron
The periodic table
o Families (groups) have common properties
Help determine the amount of valence electrons
Can only be 8 valence electrons at most (octet rule)
There are 18 families
o Periods are the rows
Determines the number of shells
They begin with very reactive alkali metals and ends with an
inert noble gas
Atomic number and atomic mass
o Atomic number is the number of protons in the nucleus and defines
an atom as a particular element
o Atomic mass is the average mass of each of that element’s isotopes
o Isotopes are different kinds of the same atom that vary in weight
, HESI study guide
o Mass – atomic number= # of neutrons
o Atomic number ALWAYS stays the same
o Mass differs because elements can have different #s of neutrons
Chemical equations
o Compounds- two or more elements combined in whole # ratios
(NaCl)
o Chemical equations- recipes for compounds
Reactants- react to produce desired compounds
Products- end result
Reactants products
Law of conservation of mass- mass cannot be created or
destroyed during a chemical reaction.
Equations must be balanced
Reaction rates, equilibrium, and reversibility
o Equilibrium- is a state in which reactants are forming products at the
same rate the products are forming reactants
o Increasing the reaction rate: increasing the temperature, increasing
the surface area, adding a catalyst, or increasing the concentration
o Increasing the temperature increases the kinetic energy and
increases their chances of contact
o Increasing the surface area gives the particles more opportunity to
come into contact with one another
o A catalyst accelerates a reaction by reducing the activation energy or
the amount of energy needed for a reaction to occur. The catalyst is
not used up in the reaction and most common examples are metals
or proteins (enzymes)
Solution and solution concentrations
o Solution- homogenous mixture or two or more substances
o Solute- the part that is being dissolved
o Solvent- the part that is doing the dissolving
o Compounds- chemical species that is formed when two or more
atoms join together chemically, by covalent or ionic bonds
o Alloys- solid solutions of metal to make new metals
o Amalgams- metal is dissolved in mercury
o Emulsion- mixtures of matter that are readily separate (oil and water)
o Concentration is expressed as weight per weight –ml/l, g/g, g/l
