AP Chemistry study guide 2026 QUESTIONS
WITH SOLUTIONS GRADED A+
enthalpy change for a reaction? - ANSWER//ΔH° =
ΣΔH°products - ΣΔH°reactants. What is the calorimeter
constant (C)? - ANSWER//It is the product of mass and
specific heat capacity, used in bomb calorimetry. What is
the effect of reversing a reaction on ΔH? - ANSWER//It
changes the sign of ΔH. What is the heat capacity of a
bomb calorimeter? - ANSWER//It is a constant value used
to calculate heat transfer in bomb calorimetry. How do you
find the enthalpy change for a reaction that cannot get wet?
- ANSWER//Use a bomb calorimeter. What is the
relationship between moles and ΔH in calorimetry? -
ANSWER//ΔH must match the coefficients of the balanced
reaction. What is the ΔH for the reaction CH3OH → H2CO
+ H2 using Hess' Law? - ANSWER//ΔH = (-676.5 + 242 +
520) = +86 kJ. How do you calculate the enthalpy change
when detonating nitroglycerin? - ANSWER//Use the
standard enthalpy of formation values for the products and
reactants. What is the specific heat capacity of the
solution in calorimetry problems? - ANSWER//Assumed to
be 4.20 J/g∙K unless stated otherwise. What is the role of
water in calorimetry? - ANSWER//It acts as the
surroundings to absorb heat from the system. What
happens to the temperature of water in an endothermic
reaction? - ANSWER//The temperature decreases. What
is the ΔH for the combustion of 1.00 g of sugar in a bomb
calorimeter? - ANSWER//Calculated using the heat gained
by water and the bomb calorimeter. What is the natural
state of bromine (Br2) at room temperature? -
ANSWER//Liquid. What is the natural state of sodium (Na)
at room temperature? - ANSWER//Solid. What is the
natural state of chlorine (Cl2) at room temperature? -
,ANSWER//Gas. What are the two main characteristics that
differentiate types of light? - ANSWER//Wavelength and
frequency What is the speed of light in a vacuum? -
ANSWER//2.998 x 10^8 m/s What is the formula to
calculate wavelength and frequency? - ANSWER//c = λ · v
What is the frequency of the radiation used in microwave
ovens? - ANSWER//2.45 x 10^9 Hz How do you convert
wavelength from nanometers to meters? - ANSWER//1 x
10^9 nm = 1 m What is the relationship between energy
and frequency? - ANSWER//E = h · v What is Planck's
constant (h)? - ANSWER//6.626 x 10^-34 J·s What is the
energy of violet light with a frequency of 7.05 x 10^14 s^-1?
- ANSWER//4.67 x 10^-19 J/photon What is the energy
per mole of orange light with a wavelength of 625 nm? -
ANSWER//191,000 J/mole What happens to electrons in
gas phase atoms when high voltage is applied? -
ANSWER//Electrons absorb energy and enter an excited
state. What is a gas emission spectrum? - ANSWER//A
spectrum that shows specific colors of light emitted by
excited electrons as they fall back to ground state. What is
the significance of a line emission spectrum? -
ANSWER//It acts as a fingerprint for the element and can
be used to identify it. What type of light causes electron
transition? - ANSWER//Ultraviolet light How many orbitals
are in the S sublevel? - ANSWER//1 orbital How many
electrons can the first energy level hold? - ANSWER//2
electrons What is the maximum number of electrons in the
second energy level? - ANSWER//8 electrons What is the
maximum number of electrons in the third energy level? -
ANSWER//18 electrons What is the maximum number of
electrons in the fourth energy level? - ANSWER//32
electrons What is the rule for filling orbitals with electrons?
- ANSWER//Electrons fill the lowest energy orbitals first.
What must be true about two electrons in the same orbital?
- ANSWER//They must spin in opposite directions. What
does an orbital diagram represent? - ANSWER//The
arrangement of electrons in an atom. What is the order of
,filling for orbitals? - ANSWER//Lowest energy orbitals are
filled first before pairing up. What is the frequency of
microwaves with a wavelength of 0.12 m? -
ANSWER//2.498 x 10^9 sec^-1 How many photons must
be absorbed to increase energy by 130 J with microwaves?
- ANSWER//7.9 x 10^25 photons What is the energy of
microwave radiation with a frequency of 2.45 x 10^9 Hz? -
ANSWER//1.62337 x 10^-24 J/photon What is the electron
configuration for Oxygen? - ANSWER//1s2 2s2 2p4 How
do you write the electron configuration for Zirconium? -
ANSWER//1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d2
What is the noble gas configuration for Sulfur? -
ANSWER//[Ne] 3s2 3p4 How many valence electrons
does Potassium have? - ANSWER//1 valence electron
What happens to an atom when it becomes an ion? -
ANSWER//It gives up or gains an electron, affecting its
valence electrons. What is the electron configuration for
Al3+? - ANSWER//1s2 2s2 2p6 (it has lost 3 valence
electrons) Define isoelectronic atoms. - ANSWER//Atoms
that have the same electron configuration. What is the
electron configuration for S2-? - ANSWER//1s2 2s2 2p6
3s2 3p6 (it has gained 2 valence electrons) What does it
mean if an element is paramagnetic? - ANSWER//It has
unpaired electrons and is very magnetic. What does it
mean if an element is diamagnetic? - ANSWER//It has all
paired electrons and is not magnetic. How does atomic
radius change as you go down a group in the Periodic
Table? - ANSWER//Atomic radius increases due to more
shells of electrons. How does atomic radius change
across a period from left to right? - ANSWER//Atomic
radius decreases due to increased effective nuclear
charge. What is the electron configuration for Neon? -
ANSWER//1s2 2s2 2p6 What is the noble gas
configuration for Potassium? - ANSWER//[Ar] 4s1 What is
the electron configuration for Argon? - ANSWER//1s2 2s2
2p6 3s2 3p6 What is the electron configuration for Zinc
(Zn)? - ANSWER//1s2 2s2 2p6 3s2 3p6 4s2 3d10 What is
, the electron configuration for Gallium? - ANSWER//[Ar]
3d10 4s2 4p1 How do you determine the number of
valence electrons in an atom? - ANSWER//By looking at
the highest energy level in the electron configuration.
What is the significance of noble gas configurations? -
ANSWER//They simplify the electron configuration by
using the nearest noble gas. What is the electron
configuration for Nitrogen? - ANSWER//1s2 2s2 2p3 What
is the electron configuration for Praseodymium? -
ANSWER//[Xe] 6s2 4f3 What does the term 'ground state
configuration' refer to? - ANSWER//The lowest energy
state of an atom's electrons. What does 'excited state
configuration' mean? - ANSWER//An atom's electrons are
in higher energy levels than in the ground state. What is
the electron configuration for Fluorine? - ANSWER//1s2
2s2 2p5 What is the electron configuration for Sulfur in an
excited state? - ANSWER//[Ne] 3s0 3p6 Which element
has the smallest atomic radius among Al, C, and Si? -
ANSWER//Carbon (C), because it has fewer energy levels.
What is the relationship between atomic radius and the
number of protons? - ANSWER//More protons result in a
smaller atomic radius when energy levels are equal. What
is ionization energy? - ANSWER//The energy required to
remove an electron from an atom. Which electrons are
removed first during ionization? - ANSWER//Valence
electrons are the first to be removed. What does a large
increase in ionization energy indicate? - ANSWER//It
indicates the removal of a core electron. How does the
atomic radius of cations compare to their parent atoms? -
ANSWER//Cations are always smaller than the atoms
from which they are derived. How does the atomic radius
of anions compare to their parent atoms? -
ANSWER//Anions are always larger than the atoms from
which they are derived. What trend is observed in the
sizes of isoelectronic ions? - ANSWER//The ion with more
protons is smaller; e.g., F- < O2- < N3-. What is electron
affinity? - ANSWER//The energy change that occurs when
WITH SOLUTIONS GRADED A+
enthalpy change for a reaction? - ANSWER//ΔH° =
ΣΔH°products - ΣΔH°reactants. What is the calorimeter
constant (C)? - ANSWER//It is the product of mass and
specific heat capacity, used in bomb calorimetry. What is
the effect of reversing a reaction on ΔH? - ANSWER//It
changes the sign of ΔH. What is the heat capacity of a
bomb calorimeter? - ANSWER//It is a constant value used
to calculate heat transfer in bomb calorimetry. How do you
find the enthalpy change for a reaction that cannot get wet?
- ANSWER//Use a bomb calorimeter. What is the
relationship between moles and ΔH in calorimetry? -
ANSWER//ΔH must match the coefficients of the balanced
reaction. What is the ΔH for the reaction CH3OH → H2CO
+ H2 using Hess' Law? - ANSWER//ΔH = (-676.5 + 242 +
520) = +86 kJ. How do you calculate the enthalpy change
when detonating nitroglycerin? - ANSWER//Use the
standard enthalpy of formation values for the products and
reactants. What is the specific heat capacity of the
solution in calorimetry problems? - ANSWER//Assumed to
be 4.20 J/g∙K unless stated otherwise. What is the role of
water in calorimetry? - ANSWER//It acts as the
surroundings to absorb heat from the system. What
happens to the temperature of water in an endothermic
reaction? - ANSWER//The temperature decreases. What
is the ΔH for the combustion of 1.00 g of sugar in a bomb
calorimeter? - ANSWER//Calculated using the heat gained
by water and the bomb calorimeter. What is the natural
state of bromine (Br2) at room temperature? -
ANSWER//Liquid. What is the natural state of sodium (Na)
at room temperature? - ANSWER//Solid. What is the
natural state of chlorine (Cl2) at room temperature? -
,ANSWER//Gas. What are the two main characteristics that
differentiate types of light? - ANSWER//Wavelength and
frequency What is the speed of light in a vacuum? -
ANSWER//2.998 x 10^8 m/s What is the formula to
calculate wavelength and frequency? - ANSWER//c = λ · v
What is the frequency of the radiation used in microwave
ovens? - ANSWER//2.45 x 10^9 Hz How do you convert
wavelength from nanometers to meters? - ANSWER//1 x
10^9 nm = 1 m What is the relationship between energy
and frequency? - ANSWER//E = h · v What is Planck's
constant (h)? - ANSWER//6.626 x 10^-34 J·s What is the
energy of violet light with a frequency of 7.05 x 10^14 s^-1?
- ANSWER//4.67 x 10^-19 J/photon What is the energy
per mole of orange light with a wavelength of 625 nm? -
ANSWER//191,000 J/mole What happens to electrons in
gas phase atoms when high voltage is applied? -
ANSWER//Electrons absorb energy and enter an excited
state. What is a gas emission spectrum? - ANSWER//A
spectrum that shows specific colors of light emitted by
excited electrons as they fall back to ground state. What is
the significance of a line emission spectrum? -
ANSWER//It acts as a fingerprint for the element and can
be used to identify it. What type of light causes electron
transition? - ANSWER//Ultraviolet light How many orbitals
are in the S sublevel? - ANSWER//1 orbital How many
electrons can the first energy level hold? - ANSWER//2
electrons What is the maximum number of electrons in the
second energy level? - ANSWER//8 electrons What is the
maximum number of electrons in the third energy level? -
ANSWER//18 electrons What is the maximum number of
electrons in the fourth energy level? - ANSWER//32
electrons What is the rule for filling orbitals with electrons?
- ANSWER//Electrons fill the lowest energy orbitals first.
What must be true about two electrons in the same orbital?
- ANSWER//They must spin in opposite directions. What
does an orbital diagram represent? - ANSWER//The
arrangement of electrons in an atom. What is the order of
,filling for orbitals? - ANSWER//Lowest energy orbitals are
filled first before pairing up. What is the frequency of
microwaves with a wavelength of 0.12 m? -
ANSWER//2.498 x 10^9 sec^-1 How many photons must
be absorbed to increase energy by 130 J with microwaves?
- ANSWER//7.9 x 10^25 photons What is the energy of
microwave radiation with a frequency of 2.45 x 10^9 Hz? -
ANSWER//1.62337 x 10^-24 J/photon What is the electron
configuration for Oxygen? - ANSWER//1s2 2s2 2p4 How
do you write the electron configuration for Zirconium? -
ANSWER//1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d2
What is the noble gas configuration for Sulfur? -
ANSWER//[Ne] 3s2 3p4 How many valence electrons
does Potassium have? - ANSWER//1 valence electron
What happens to an atom when it becomes an ion? -
ANSWER//It gives up or gains an electron, affecting its
valence electrons. What is the electron configuration for
Al3+? - ANSWER//1s2 2s2 2p6 (it has lost 3 valence
electrons) Define isoelectronic atoms. - ANSWER//Atoms
that have the same electron configuration. What is the
electron configuration for S2-? - ANSWER//1s2 2s2 2p6
3s2 3p6 (it has gained 2 valence electrons) What does it
mean if an element is paramagnetic? - ANSWER//It has
unpaired electrons and is very magnetic. What does it
mean if an element is diamagnetic? - ANSWER//It has all
paired electrons and is not magnetic. How does atomic
radius change as you go down a group in the Periodic
Table? - ANSWER//Atomic radius increases due to more
shells of electrons. How does atomic radius change
across a period from left to right? - ANSWER//Atomic
radius decreases due to increased effective nuclear
charge. What is the electron configuration for Neon? -
ANSWER//1s2 2s2 2p6 What is the noble gas
configuration for Potassium? - ANSWER//[Ar] 4s1 What is
the electron configuration for Argon? - ANSWER//1s2 2s2
2p6 3s2 3p6 What is the electron configuration for Zinc
(Zn)? - ANSWER//1s2 2s2 2p6 3s2 3p6 4s2 3d10 What is
, the electron configuration for Gallium? - ANSWER//[Ar]
3d10 4s2 4p1 How do you determine the number of
valence electrons in an atom? - ANSWER//By looking at
the highest energy level in the electron configuration.
What is the significance of noble gas configurations? -
ANSWER//They simplify the electron configuration by
using the nearest noble gas. What is the electron
configuration for Nitrogen? - ANSWER//1s2 2s2 2p3 What
is the electron configuration for Praseodymium? -
ANSWER//[Xe] 6s2 4f3 What does the term 'ground state
configuration' refer to? - ANSWER//The lowest energy
state of an atom's electrons. What does 'excited state
configuration' mean? - ANSWER//An atom's electrons are
in higher energy levels than in the ground state. What is
the electron configuration for Fluorine? - ANSWER//1s2
2s2 2p5 What is the electron configuration for Sulfur in an
excited state? - ANSWER//[Ne] 3s0 3p6 Which element
has the smallest atomic radius among Al, C, and Si? -
ANSWER//Carbon (C), because it has fewer energy levels.
What is the relationship between atomic radius and the
number of protons? - ANSWER//More protons result in a
smaller atomic radius when energy levels are equal. What
is ionization energy? - ANSWER//The energy required to
remove an electron from an atom. Which electrons are
removed first during ionization? - ANSWER//Valence
electrons are the first to be removed. What does a large
increase in ionization energy indicate? - ANSWER//It
indicates the removal of a core electron. How does the
atomic radius of cations compare to their parent atoms? -
ANSWER//Cations are always smaller than the atoms
from which they are derived. How does the atomic radius
of anions compare to their parent atoms? -
ANSWER//Anions are always larger than the atoms from
which they are derived. What trend is observed in the
sizes of isoelectronic ions? - ANSWER//The ion with more
protons is smaller; e.g., F- < O2- < N3-. What is electron
affinity? - ANSWER//The energy change that occurs when
