CHEM 105 PRACTICE EXAM
QUESTIONS AND DETAILED
SOLUTIONS 2026
▶ write the formula for iron (III) nitrate. Answer: Fe^+3 NO3^-
Fe(NO3)3 ---> Fe has pos 3 charge, so NO3 ^-needs a pos 3 charge so it
is balanced. (so Fe has pos 3, NO3- has -3)
▶ isomers. Answer: molecules with the same atoms, different connectivity
ex: C3H6 can be drawn in different ways, don't always have the same
functional group
▶ VESPR theory. Answer: because electron pairs repel, molecules adjust
their shapes so that valence electrons pairs move as far apart as possible
▶ electron geometry. Answer: each bond (1, 2, 3) and each LP count as
one area of electrons
a) Four areas of electrons = tetrahedron (109.5)
b) 3 areas of e- = trigonal planar (120)
c) 2 areas of e- = linear (180)
▶ molecular geometry. Answer: if no lone pairs, then the same as electron
geometry
a) 3 bond areas + 1 LP = trigonal pyramidal
b) 2 bonds + 1 LP
2 bonds + 2 LP
= bent
▶ line angle structures. Answer: ***Practice***
Rules:
carbon at every end and bend
leave off H's bond to carbons
zig zag the chain
▶ functional groups. Answer: **memorize structures (IMPORTANT)**
, ▶ writing chemical reactions. Answer:
▶ conservation of mass. Answer:
▶ balancing reactions. Answer:
▶ what is 2100 MHz (megahertz) in scientific notation?. Answer: 2.1 x
10^9
▶ how many liters are there in 3.54 ML? *notice capital M*. Answer:
3,540,000
▶ 2 cubes are the same size, one is copper and other is aluminum. what is
true about mass and volume?. Answer: different masses, same volume
▶ T or F: the density of a pure metal depends on its size. Answer: False
▶ process of matter going from gas directly to solid?. Answer: deposition
▶ A solid going directly to a gas. Answer: sublimation
▶ Which set of elements would you expect similar chemical properties?.
Answer: Al, In, Tl (going down on periodic table)
▶ how is periodic table organized?. Answer: increasing atomic number
▶ how many electrons does a fluorine atom have?. Answer: 9
▶ Bromine has two isotopes, 79 Br and 81 Br. Looking at periodic table,
which is most abundant isotope?
79Br
80Br
81Br. Answer: 79Br
▶ how many electrons shared in double bond?. Answer: 4
▶ what is the formula for diphosphorus pentasulfide. Answer: P2S5
QUESTIONS AND DETAILED
SOLUTIONS 2026
▶ write the formula for iron (III) nitrate. Answer: Fe^+3 NO3^-
Fe(NO3)3 ---> Fe has pos 3 charge, so NO3 ^-needs a pos 3 charge so it
is balanced. (so Fe has pos 3, NO3- has -3)
▶ isomers. Answer: molecules with the same atoms, different connectivity
ex: C3H6 can be drawn in different ways, don't always have the same
functional group
▶ VESPR theory. Answer: because electron pairs repel, molecules adjust
their shapes so that valence electrons pairs move as far apart as possible
▶ electron geometry. Answer: each bond (1, 2, 3) and each LP count as
one area of electrons
a) Four areas of electrons = tetrahedron (109.5)
b) 3 areas of e- = trigonal planar (120)
c) 2 areas of e- = linear (180)
▶ molecular geometry. Answer: if no lone pairs, then the same as electron
geometry
a) 3 bond areas + 1 LP = trigonal pyramidal
b) 2 bonds + 1 LP
2 bonds + 2 LP
= bent
▶ line angle structures. Answer: ***Practice***
Rules:
carbon at every end and bend
leave off H's bond to carbons
zig zag the chain
▶ functional groups. Answer: **memorize structures (IMPORTANT)**
, ▶ writing chemical reactions. Answer:
▶ conservation of mass. Answer:
▶ balancing reactions. Answer:
▶ what is 2100 MHz (megahertz) in scientific notation?. Answer: 2.1 x
10^9
▶ how many liters are there in 3.54 ML? *notice capital M*. Answer:
3,540,000
▶ 2 cubes are the same size, one is copper and other is aluminum. what is
true about mass and volume?. Answer: different masses, same volume
▶ T or F: the density of a pure metal depends on its size. Answer: False
▶ process of matter going from gas directly to solid?. Answer: deposition
▶ A solid going directly to a gas. Answer: sublimation
▶ Which set of elements would you expect similar chemical properties?.
Answer: Al, In, Tl (going down on periodic table)
▶ how is periodic table organized?. Answer: increasing atomic number
▶ how many electrons does a fluorine atom have?. Answer: 9
▶ Bromine has two isotopes, 79 Br and 81 Br. Looking at periodic table,
which is most abundant isotope?
79Br
80Br
81Br. Answer: 79Br
▶ how many electrons shared in double bond?. Answer: 4
▶ what is the formula for diphosphorus pentasulfide. Answer: P2S5
