1. In an acid-base titration, if 25 mL of NaOH solution is required to neutralize 40 mL of HCl, what is the concentration of NaOH? A. 0.25 M B. 0.4 M C. 0.5 M D. 0.1 M
2. If 10 mL of 0.1 M HCl is used to neutralize 10 mL of NaOH, what is the molarity of NaOH? A. 0.1 M B. 0.05 M C. 0.2 M D. 0.3 M
3. Which of these materials is commonly used as an electrode in a standard electrochemical cell? A. Copper B. Zinc C. Lead D. Graphite
4. In a reversible adiabatic process, the work done by the system is: A. Equal to the heat absorbed B. Zero C. Negative D. Equal to the change in internal energy
5. An element has 12 protons, 12 neutrons, and 12 electrons. What is the charge of its ion if it loses 2 electrons? A. +2 B. -2 C. 0 D. +1
6. Which of the following factors does NOT affect the rate of evaporation of a liquid? A. Surface area B. Temperature C. Air pressure D. Concentration of solute
8. What is the limiting reagent when 10 g of hydrogen reacts with 20 g of oxygen in the reaction 2H2 + O2 → 2H2O? (Molar mass of H2 = 2 g/mol, O2 = 32 g/mol) A. H2 B. O2 C. Both D. Neither
9. If 10 g of sodium reacts with 10 g of chlorine gas, which reactant is in excess? (Molar mass of Na = 23 g/mol, Cl2 = 71 g/mol) A. Sodium B. Chlorine C. Both are in excess D. Neither
10. What is the process in which a solid turns directly into a gas? A. Melting B. Sublimation C. Deposition D. Freezing
11. Which of the following changes in oxidation states represents a reduction? A. Fe²⁺ → Fe³⁺ B. Cu → Cu²⁺ C. O₂ → O²⁻ D. MnO₂ → Mn³⁺
13. What happens to the equilibrium position if the concentration of a product is increased? A. The equilibrium shifts to the left B. The equilibrium shifts to the right C. The equilibrium position remains unchanged D. The reaction stops
14. Which of the following bases is weak and has a relatively low pKb? A. NaOH B. NH₃ C. KOH D. Ca(OH)₂
15. Which of the following elements has the lowest electron affinity? A. Oxygen B. Sodium C. Chlorine D. Nitrogen
16. The change in enthalpy (∆H) during an isobaric process is equal to: A. Heat absorbed or released B. Work done by the system C. Change in temperature D. Change in pressure
17. In the reaction 2A → B, the rate constant is 0.02 mol⁻¹·L·s⁻¹. What is the rate of reaction when the concentration of A is 0.1 M? A. 0.02 mol/s B. 0.04 mol/s C. 0.2 mol/s D. 0.002 mol/s
20. What does the ideal gas law assume about the behavior of gas molecules? A. Gas molecules are large and have significant volume B. Gas molecules are in constant random motion and do not interact C. Gas molecules move at very slow speeds D. Gas molecules are highly attracted to each other
21. In 1 mole of any element, the number of particles is... A. 6.022 x 10^23 B. 6.022 x 10^24 C. 12.044 x 10^23 D. 1 x 10^24
22. What is the trend in electronegativity across a period? A. It decreases B. It increases C. It remains constant D. It varies randomly
25. How many atoms are there in 0.5 moles of calcium (Ca)? A. 3.0 x 10^23 B. 1.0 x 10^24 C. 6.0 x 10^23 D. 3.0 x 10^22
26. Which metal is found in the Periodic Table as a liquid at room temperature? A. Mercury B. Gallium C. Lead D. Sodium
27. Which of the following is a common feature of primary cells? A. They can be recharged B. They have a limited lifespan C. They provide higher current D. They are usually cheaper
28. How many atoms are present in 1 mole of oxygen gas (O2)? A. 1.0 x 10^23 B. 2.0 x 10^23 C. 6.0 x 10^23 D. 12.0 x 10^23
30. What is the integrated rate law for a first-order reaction? A. ln[A] = -kt + ln[A₀] B. [A] = [A₀] - kt C. 1/[A] = 1/[A₀] + kt D. [A] = [A₀] + kt
31. In a concentration cell, the cell potential is dependent on: A. The concentration of the ions B. The temperature C. The material of the electrode D. None of the above
32. Given the equation for the ionization of acetic acid: CH₃COOH ⇌ H⁺ + CH₃COO⁻, if the concentration of CH₃COOH is 0.2 M and the concentration of H⁺ is 0.01 M, what is the value of the acid dissociation constant (K_a)? A. 5 × 10⁻⁶ B. 5 × 10⁻⁴ C. 1 × 10⁻³ D. 1 × 10⁻⁴
33. The Nernst equation is used to calculate the cell potential of a non-standard electrochemical cell. What does the 'n' in the equation represent? A. Number of moles of the substance B. Number of moles of electrons involved in the reaction C. Number of atoms in the system D. None of the above
34. Which element is located in Group 1 of the Periodic Table? A. Lithium B. Sodium C. Potassium D. Hydrogen
35. How many grams of calcium carbonate (CaCO3) will be produced when 10 g of calcium oxide (CaO) reacts with excess carbon dioxide (CO2)? (Molar mass of CaO = 56 g/mol, CaCO3 = 100 g/mol) A. 40 g B. 50 g C. 60 g D. 70 g
36. What happens to the pressure of a gas if the volume is halved at constant temperature? A. The pressure remains the same B. The pressure doubles C. The pressure is halved D. The pressure quadruples
37. An atom has 15 protons, 15 electrons, and 16 neutrons. What is its atomic number? A. 14 B. 16 C. 15 D. 12
38. In the reaction CO(g) + Cl₂(g) ⇌ COCl₂(g), increasing the pressure will cause the equilibrium to shift towards A. The side with more gas molecules B. The side with fewer gas molecules C. The products D. The reactants
40. What is the main reason for the increase in ionization energy across a period? A. Increased shielding effect B. Decreased nuclear charge C. Increased nuclear attraction D. Increased electron shielding
42. Which of the following expressions correctly represents the integrated rate law for a second-order reaction? A. 1/[A] = 1/[A₀] + kt B. ln[A] = -kt + ln[A₀] C. [A] = [A₀] + kt D. 1/[A] = -kt + 1/[A₀]
43. In a closed container, the concentration of H₂, I₂, and HI at equilibrium are 0.1 M, 0.1 M, and 0.3 M, respectively. What is the equilibrium constant for the reaction H₂(g) + I₂(g) ⇌ 2HI(g)? A. 0.1 B. 0.3 C. 0.9 D. 0.03
44. Which element has a higher electron affinity than chlorine? A. Fluorine B. Bromine C. Iodine D. Neon
45. How many neutrons are in an isotope of chlorine with mass number 37? (Atomic number of chlorine = 17) A. 17 neutrons B. 18 neutrons C. 20 neutrons D. 19 neutrons
46. In a reaction mechanism, the slowest step is called the: A. Rate-determining step B. Fast step C. Intermediate step D. Catalytic step
47. For a first-order reaction, if the concentration of the reactant is halved, what happens to the rate of reaction? A. It remains the same B. It is halved C. It doubles D. It is quadrupled
48. How many atoms are in 0.5 moles of a substance? A. 3.0 x 10^23 B. 6.0 x 10^23 C. 1.0 x 10^24 D. 2.0 x 10^23
49. What is the principle behind a fuel cell? A. Electrolysis of water B. Oxidation-reduction reaction in a fuel C. Combustion of hydrogen D. Hydrolysis of hydrogen
50. The formula for work done in an isothermal process is: A. W = P(Vf - Vi) B. W = nRT ln(Vf / Vi) C. W = ∆U + ∆Q D. W = nC∆T