ACS FIRST YEAR CHEMISTRY EXAM QUESTIONS WITH CORRECT ANSWERS LATEST
UPDATE 2026/2027
ionization energy - Answers the amount of energy required to remove an electron from an atom.
- increases from bottom left to top right
atomic radius - Answers distance from center to edge of an atom.
- decreases from bottom left to top right
electronegativity - Answers how much an atom "pulls" on electrons in a bond.
- increases from bottom left to top right
metallic character - Answers how easily an atom gives up electrons to form a positive ion.
- decreases from bottom left to top right
reactivity - Answers how easily an atom gains or loses electrons.
- the closer an element is to completing a full valence shell, the more likely they are to react
chemically
coulomb's law - Answers determines how much energy is present in an ionic bond.
E = (kq1 * q2)/r
r: length of bond
E: amt of energy
k: constant
q1 & q2: charges on each ion
bond length - Answers - the smaller the atoms, the shorter the bond length.
- the more bonds between atoms, the shorter the bond length.
- the shorter the bond length, the greater the energy.
metallic bond - Answers metal atoms donate valence electrons to become cations; these
valence electrons more freely throughout the sample, producing an attractive force that keeps
the metal cations in place.
bond energy - Answers net release in energy (ΔH) = (energy it takes to break bonds) - (energy it
takes to make new bonds)
, breaking bonds: uses energy
forming bonds: releases energy
chemical equilibrium - Answers forward & reverse reaction rates are equal; temperature &
pressure are maintained; system is closed.
aA + bB ⇌ cC + dD
***concentration of reactants and products are not necessarily equal!!
equilibrium constant: K_eq - Answers Keq = ([C]^c [D]^d)/([A]^a [B]^b)
- [ ] means "concentration of"
[products]/[reactants]
dynamic equilibrium - Answers rate of forward reaction equals rate of reverse reaction; constant
but not equal concentration of products and reactants.
Keq > 1 = forward reaction favored = spontaneous
Keq < 1 = reverse reaction favored = not spontaneous
la châtelier's principle (equilibrium) - Answers equilibrium shifts in the opposite direction of the
side where more is added.
heat (& equilibrium) - Answers equilibrium shifts in the opposite direction of the side where the
heat is on.
A + B + heat ⇌ C + D
- increases heat: equilibrium shifts right
- decreases heat: equilibrium shifts left
pressure (& equilibrium) - Answers when pressure is decreased or volume increases,equilibrium
shifts in the direction that produces fewer moles of gas.
T/F: catalysts do not affect equilibrium
T/F: solids are not included in equilibrium expressions - Answers F
T
UPDATE 2026/2027
ionization energy - Answers the amount of energy required to remove an electron from an atom.
- increases from bottom left to top right
atomic radius - Answers distance from center to edge of an atom.
- decreases from bottom left to top right
electronegativity - Answers how much an atom "pulls" on electrons in a bond.
- increases from bottom left to top right
metallic character - Answers how easily an atom gives up electrons to form a positive ion.
- decreases from bottom left to top right
reactivity - Answers how easily an atom gains or loses electrons.
- the closer an element is to completing a full valence shell, the more likely they are to react
chemically
coulomb's law - Answers determines how much energy is present in an ionic bond.
E = (kq1 * q2)/r
r: length of bond
E: amt of energy
k: constant
q1 & q2: charges on each ion
bond length - Answers - the smaller the atoms, the shorter the bond length.
- the more bonds between atoms, the shorter the bond length.
- the shorter the bond length, the greater the energy.
metallic bond - Answers metal atoms donate valence electrons to become cations; these
valence electrons more freely throughout the sample, producing an attractive force that keeps
the metal cations in place.
bond energy - Answers net release in energy (ΔH) = (energy it takes to break bonds) - (energy it
takes to make new bonds)
, breaking bonds: uses energy
forming bonds: releases energy
chemical equilibrium - Answers forward & reverse reaction rates are equal; temperature &
pressure are maintained; system is closed.
aA + bB ⇌ cC + dD
***concentration of reactants and products are not necessarily equal!!
equilibrium constant: K_eq - Answers Keq = ([C]^c [D]^d)/([A]^a [B]^b)
- [ ] means "concentration of"
[products]/[reactants]
dynamic equilibrium - Answers rate of forward reaction equals rate of reverse reaction; constant
but not equal concentration of products and reactants.
Keq > 1 = forward reaction favored = spontaneous
Keq < 1 = reverse reaction favored = not spontaneous
la châtelier's principle (equilibrium) - Answers equilibrium shifts in the opposite direction of the
side where more is added.
heat (& equilibrium) - Answers equilibrium shifts in the opposite direction of the side where the
heat is on.
A + B + heat ⇌ C + D
- increases heat: equilibrium shifts right
- decreases heat: equilibrium shifts left
pressure (& equilibrium) - Answers when pressure is decreased or volume increases,equilibrium
shifts in the direction that produces fewer moles of gas.
T/F: catalysts do not affect equilibrium
T/F: solids are not included in equilibrium expressions - Answers F
T
