CHEM 120 Final Exam Review Questions
with Answers
significant figures - -a digit that is either reliably known or closely estimated
- Significant Figure Rules - -1. All non-zero digits are always significant
2. Zeroes between non-zero digits are always significant
3. Zeroes to left of first non-zero digit (either before or after decimal point)
are never significant
4. Zeroes to the right of last non-zero digit
a. after decimal point are always significant
b. which are before decimal point are not significant
- conversion factor - -relationship between two quantities expressed as a
fraction
- dimensional analysis - -conversion of a measurement in one unit into
another by the use of conversion factors
- True - -T/F: number of protons never changes according to periodic table
- number of protons - -atomic number=_______________________
- number of neutrons - -mass number=_______________________
- isotopes - -atoms with same number of protons (same electron) but
different number of neutrons
- atomic mass - -weighted average of the isotopic masses of all stable
isotopes of an element
- compound - -substance composed of 2+ elements that are chemically
combined
- molecular compound - -compound in which atoms are held together by
covalent bonds
- ionic bond - -nonmetal and metal (giving away of electrons by one and
receiving by the other); electrostatic interactions between positive and
negative ions
- covalent bond - -2 nonmetals (sharing of bonds); the sharing of electrons
between two atoms
, - ion - -atom that has an electrostatic charge
- cation - -positively charged atom
- anion - -negatively charged atom
- formula unit - -simplest whole number ratio of ions in ionic compound
- polyatomic ion - -groups of covalently-bonded atoms that have an overall
charge
- physical change - -change in a substance that does not change its
composition
- extensive physical properties - -properties that depend on the amount of
matter present (ex-mass, volume)
- intensive physical properties - -properties that do not depend on the
amount of matter present (ex-color, clarity, physical state, melting/boiling
points, density)
- chemical change - -the transformation of a substance into a different
substance
(ex-rusting iron, burning coal, baking soda reacting with vinegar
- density - -the ratio of a substance's mass to its volume D=m/V
- mixture - -2 or more substances which are physically combined
- heterogeneous mixture - -non-uniform mixture containing two or more
phases with definite boundaries between them
- homogeneous mixture - -uniform mixture which contains only one phase
- solution - -another word for homogeneous mixture, but usually refers to a
liquid mixture
- compound mixtures - -The following are characteristics of:
-pure substance
-2+ elements chemically combined
-final compound does NOT have properties of original
-cannot be separated by physical methods
- homogeneous mixtures - --NOT pure substance
-2+ substances physically combined
-final mix has the properties of each of the components that make it up
with Answers
significant figures - -a digit that is either reliably known or closely estimated
- Significant Figure Rules - -1. All non-zero digits are always significant
2. Zeroes between non-zero digits are always significant
3. Zeroes to left of first non-zero digit (either before or after decimal point)
are never significant
4. Zeroes to the right of last non-zero digit
a. after decimal point are always significant
b. which are before decimal point are not significant
- conversion factor - -relationship between two quantities expressed as a
fraction
- dimensional analysis - -conversion of a measurement in one unit into
another by the use of conversion factors
- True - -T/F: number of protons never changes according to periodic table
- number of protons - -atomic number=_______________________
- number of neutrons - -mass number=_______________________
- isotopes - -atoms with same number of protons (same electron) but
different number of neutrons
- atomic mass - -weighted average of the isotopic masses of all stable
isotopes of an element
- compound - -substance composed of 2+ elements that are chemically
combined
- molecular compound - -compound in which atoms are held together by
covalent bonds
- ionic bond - -nonmetal and metal (giving away of electrons by one and
receiving by the other); electrostatic interactions between positive and
negative ions
- covalent bond - -2 nonmetals (sharing of bonds); the sharing of electrons
between two atoms
, - ion - -atom that has an electrostatic charge
- cation - -positively charged atom
- anion - -negatively charged atom
- formula unit - -simplest whole number ratio of ions in ionic compound
- polyatomic ion - -groups of covalently-bonded atoms that have an overall
charge
- physical change - -change in a substance that does not change its
composition
- extensive physical properties - -properties that depend on the amount of
matter present (ex-mass, volume)
- intensive physical properties - -properties that do not depend on the
amount of matter present (ex-color, clarity, physical state, melting/boiling
points, density)
- chemical change - -the transformation of a substance into a different
substance
(ex-rusting iron, burning coal, baking soda reacting with vinegar
- density - -the ratio of a substance's mass to its volume D=m/V
- mixture - -2 or more substances which are physically combined
- heterogeneous mixture - -non-uniform mixture containing two or more
phases with definite boundaries between them
- homogeneous mixture - -uniform mixture which contains only one phase
- solution - -another word for homogeneous mixture, but usually refers to a
liquid mixture
- compound mixtures - -The following are characteristics of:
-pure substance
-2+ elements chemically combined
-final compound does NOT have properties of original
-cannot be separated by physical methods
- homogeneous mixtures - --NOT pure substance
-2+ substances physically combined
-final mix has the properties of each of the components that make it up
