CHEM 120 UNIT 8 FINAL EXAM PRACTICE TEST
2026 QUESTIONS ANSWERS GRADED A+
◉ Significant Figure Rules. Answer: 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. Answer: relationship between two quantities
expressed as a fraction
◉ dimensional analysis. Answer: conversion of a measurement in
one unit into another by the use of conversion factors
◉ True. Answer: T/F: number of protons never changes according to
periodic table
◉ number of protons. Answer: atomic number=_______________________
, ◉ number of neutrons. Answer: mass number=_______________________
◉ isotopes. Answer: atoms with same number of protons (same
electron) but different number of neutrons
◉ atomic mass. Answer: weighted average of the isotopic masses of
all stable isotopes of an element
◉ compound. Answer: substance composed of 2+ elements that are
chemically combined
◉ molecular compound. Answer: compound in which atoms are held
together by covalent bonds
◉ ionic bond. Answer: nonmetal and metal (giving away of electrons
by one and receiving by the other); electrostatic interactions
between positive and negative ions
◉ covalent bond. Answer: 2 nonmetals (sharing of bonds); the
sharing of electrons between two atoms
◉ ion. Answer: atom that has an electrostatic charge
2026 QUESTIONS ANSWERS GRADED A+
◉ Significant Figure Rules. Answer: 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. Answer: relationship between two quantities
expressed as a fraction
◉ dimensional analysis. Answer: conversion of a measurement in
one unit into another by the use of conversion factors
◉ True. Answer: T/F: number of protons never changes according to
periodic table
◉ number of protons. Answer: atomic number=_______________________
, ◉ number of neutrons. Answer: mass number=_______________________
◉ isotopes. Answer: atoms with same number of protons (same
electron) but different number of neutrons
◉ atomic mass. Answer: weighted average of the isotopic masses of
all stable isotopes of an element
◉ compound. Answer: substance composed of 2+ elements that are
chemically combined
◉ molecular compound. Answer: compound in which atoms are held
together by covalent bonds
◉ ionic bond. Answer: nonmetal and metal (giving away of electrons
by one and receiving by the other); electrostatic interactions
between positive and negative ions
◉ covalent bond. Answer: 2 nonmetals (sharing of bonds); the
sharing of electrons between two atoms
◉ ion. Answer: atom that has an electrostatic charge
