General Chemistry Chapter 1, 2, 3 Test
Questions and Answers | Latest Update |
2024/2025 | 100% Pass
What is the principle behind using chromatography for separating mixtures?
✔✔ Chromatography separates mixtures based on the differential affinities of compounds for a
stationary phase and a mobile phase, allowing components to be isolated and analyzed.
How does the concept of entropy relate to the spontaneity of a chemical reaction?
✔✔ Entropy measures the disorder or randomness in a system. A reaction tends to be
spontaneous if it results in an increase in the total entropy of the system and its surroundings.
What are the characteristic properties of gases according to the ideal gas law, and how do real
gases deviate from this law?
✔✔ Gases are characterized by properties such as pressure, volume, temperature, and number of
moles, and the ideal gas law assumes that gases behave ideally with no intermolecular forces.
Real gases deviate from this law at high pressures and low temperatures due to these
intermolecular interactions.
1
,What is the difference between a strong base and a weak base in terms of their dissociation in
water?
✔✔ A strong base dissociates completely into ions in water, while a weak base only partially
dissociates, establishing an equilibrium between the base and its ions.
How does the solubility of a solute in a solvent change with temperature and pressure?
✔✔ For most solids, solubility increases with temperature, while for gases, solubility decreases
with increasing temperature and increases with increasing pressure.
What is the concept of a reaction rate, and what factors can affect it?
✔✔ The reaction rate is the speed at which reactants are converted into products. Factors
affecting it include temperature, concentration of reactants, surface area, and the presence of a
catalyst.
What is the difference between molecular orbitals and atomic orbitals in the context of bonding?
✔✔ Molecular orbitals are formed from the combination of atomic orbitals when atoms bond,
allowing for the distribution of electrons over the entire molecule, while atomic orbitals are the
regions around an atom where electrons are likely to be found.
2
,How do you calculate the average atomic mass of an element given the relative abundances of its
isotopes?
✔✔ The average atomic mass is calculated by multiplying the atomic mass of each isotope by its
relative abundance (expressed as a fraction) and summing these products.
What is the concept of partial pressure in a mixture of gases, and how is it related to the total
pressure?
✔✔ Partial pressure is the pressure exerted by an individual gas in a mixture, and it is related to
the total pressure by Dalton's law, which states that the total pressure is the sum of the partial
pressures of all gases in the mixture.
What is the role of a catalyst in a reaction mechanism, and how does it affect the activation
energy?
✔✔ A catalyst provides an alternative reaction pathway with a lower activation energy, thereby
increasing the rate of the reaction without being consumed in the process.
What is the role of a buffer in a biological system, and how does it help maintain homeostasis?
✔✔ A buffer in a biological system helps maintain homeostasis by neutralizing small amounts of
acids or bases, thereby stabilizing the pH of the system.
3
, How do you calculate the empirical formula of a compound from its percentage composition?
✔✔ To calculate the empirical formula from percentage composition, convert the percentages to
grams, then to moles, and finally find the simplest whole-number ratio of the elements.
What is the concept of standard enthalpy of formation, and how is it used in calculating reaction
enthalpy?
✔✔ The standard enthalpy of formation is the heat change when one mole of a compound is
formed from its elements in their standard states. It is used to calculate reaction enthalpy by
summing the enthalpy changes for formation of products and subtracting the enthalpy changes
for formation of reactants.
What is the difference between a physical change and a chemical change, and how can you
distinguish between them?
✔✔ A physical change affects the form of a substance but not its chemical composition, such as
melting or boiling. A chemical change results in the formation of new substances with different
properties, such as burning or rusting.
How does the concept of dynamic equilibrium apply to a system at chemical equilibrium?
4
Questions and Answers | Latest Update |
2024/2025 | 100% Pass
What is the principle behind using chromatography for separating mixtures?
✔✔ Chromatography separates mixtures based on the differential affinities of compounds for a
stationary phase and a mobile phase, allowing components to be isolated and analyzed.
How does the concept of entropy relate to the spontaneity of a chemical reaction?
✔✔ Entropy measures the disorder or randomness in a system. A reaction tends to be
spontaneous if it results in an increase in the total entropy of the system and its surroundings.
What are the characteristic properties of gases according to the ideal gas law, and how do real
gases deviate from this law?
✔✔ Gases are characterized by properties such as pressure, volume, temperature, and number of
moles, and the ideal gas law assumes that gases behave ideally with no intermolecular forces.
Real gases deviate from this law at high pressures and low temperatures due to these
intermolecular interactions.
1
,What is the difference between a strong base and a weak base in terms of their dissociation in
water?
✔✔ A strong base dissociates completely into ions in water, while a weak base only partially
dissociates, establishing an equilibrium between the base and its ions.
How does the solubility of a solute in a solvent change with temperature and pressure?
✔✔ For most solids, solubility increases with temperature, while for gases, solubility decreases
with increasing temperature and increases with increasing pressure.
What is the concept of a reaction rate, and what factors can affect it?
✔✔ The reaction rate is the speed at which reactants are converted into products. Factors
affecting it include temperature, concentration of reactants, surface area, and the presence of a
catalyst.
What is the difference between molecular orbitals and atomic orbitals in the context of bonding?
✔✔ Molecular orbitals are formed from the combination of atomic orbitals when atoms bond,
allowing for the distribution of electrons over the entire molecule, while atomic orbitals are the
regions around an atom where electrons are likely to be found.
2
,How do you calculate the average atomic mass of an element given the relative abundances of its
isotopes?
✔✔ The average atomic mass is calculated by multiplying the atomic mass of each isotope by its
relative abundance (expressed as a fraction) and summing these products.
What is the concept of partial pressure in a mixture of gases, and how is it related to the total
pressure?
✔✔ Partial pressure is the pressure exerted by an individual gas in a mixture, and it is related to
the total pressure by Dalton's law, which states that the total pressure is the sum of the partial
pressures of all gases in the mixture.
What is the role of a catalyst in a reaction mechanism, and how does it affect the activation
energy?
✔✔ A catalyst provides an alternative reaction pathway with a lower activation energy, thereby
increasing the rate of the reaction without being consumed in the process.
What is the role of a buffer in a biological system, and how does it help maintain homeostasis?
✔✔ A buffer in a biological system helps maintain homeostasis by neutralizing small amounts of
acids or bases, thereby stabilizing the pH of the system.
3
, How do you calculate the empirical formula of a compound from its percentage composition?
✔✔ To calculate the empirical formula from percentage composition, convert the percentages to
grams, then to moles, and finally find the simplest whole-number ratio of the elements.
What is the concept of standard enthalpy of formation, and how is it used in calculating reaction
enthalpy?
✔✔ The standard enthalpy of formation is the heat change when one mole of a compound is
formed from its elements in their standard states. It is used to calculate reaction enthalpy by
summing the enthalpy changes for formation of products and subtracting the enthalpy changes
for formation of reactants.
What is the difference between a physical change and a chemical change, and how can you
distinguish between them?
✔✔ A physical change affects the form of a substance but not its chemical composition, such as
melting or boiling. A chemical change results in the formation of new substances with different
properties, such as burning or rusting.
How does the concept of dynamic equilibrium apply to a system at chemical equilibrium?
4
