#1
Which of the following is a characteristic of a chemical reaction?
Change in color
Change in mass
Change in volume
Change in temperature
#2
What is the role of an acid in a chemical reaction?
To donate protons
To accept protons
To release electrons
To increase the pH of the solution
#3
Which of the following is a chemical property?
Color
Density
Boiling point
Reactivity
#4
Which of the following is a characteristic of a reversible reaction?
It produces only one product
It can proceed in both forward and reverse directions
It always goes to completion
It releases heat
#5
What is the unit of concentration typically used for solutions?
#6
What is the purpose of a catalyst in a chemical reaction?
To increase the activation energy
To decrease the rate of reaction
To change the equilibrium constant
To provide an alternative reaction pathway with lower activation energy
#7
What is the balanced equation for the reaction between sodium hydroxide (NaOH) and hydrochloric acid (HCl)?
NaOH + HCl → NaCl + H2O
NaOH + HCl → NaCl + H2 + O2
2NaOH + HCl → NaCl + H2O
NaOH + 2HCl → NaCl + H2O
#8
What is the role of a catalyst in a chemical reaction?
To increase the rate of reaction
To decrease the rate of reaction
To initiate the reaction
To change the products of the reaction
#9
In the reaction: 2H2(g) + O2(g) → 2H2O(g), what is the limiting reactant when 3 moles of H2 and 2 moles of O2 are reacted?
H2
O2
Both are limiting reactants
Neither is a limiting reactant
#10
What is the principle behind the process of fractional distillation?
Evaporation
Decomposition
Fractionation
Filtration
#11
Which statement about catalysts is true?
They are consumed in a reaction
They are specific to only one type of reaction
They alter the equilibrium constant of a reaction
They provide an alternative reaction pathway with lower activation energy
#12
What does the term 'dynamic equilibrium' refer to in a chemical reaction?
The rate of the forward reaction is equal to the rate of the reverse reaction
The concentrations of reactants and products remain constant over time
The reaction proceeds to completion
The reaction occurs at a constant temperature
#13
According to Le Chatelier's principle, what happens to a system at equilibrium when there is an increase in pressure?
The equilibrium shifts to the side with fewer moles of gas
The equilibrium shifts to the side with more moles of gas
The equilibrium remains unaffected
The equilibrium completely stops
#14
What is the equilibrium constant expression (Kc) for the reaction: N2(g) + 3H2(g) ⇌ 2NH3(g)?
[NH3]^2 / [N2][H2]^3
[NH3] / [N2][H2]^3
[NH3]^3 / [N2][H2]
[NH3]^2 / [N2][H2]^2
#15
What is the effect of increasing the temperature on an endothermic reaction at equilibrium?
The equilibrium shifts to favor the reactants
The equilibrium shifts to favor the products
The equilibrium remains unaffected
The equilibrium becomes inactive
#16
What is the effect of adding a catalyst to a reaction at equilibrium?
It increases the rate of the forward reaction only
It increases the rate of the reverse reaction only
It increases the rate of both the forward and reverse reactions equally
It has no effect on the equilibrium position
#17
What is the effect of increasing the concentration of reactants on the rate of a reaction?
It increases the rate
It decreases the rate
It has no effect on the rate
It depends on the specific reaction
#18
What is the function of a buffer solution?
To resist changes in pH
To accelerate reaction rates
To increase the solubility of solutes
To neutralize strong acids