day 1

1. Which of the following is the primary role of greenhouse gases (GHGs) in Earth’s atmosphere?

a. To trap heat and regulate the planet’s temperature

2. Which greenhouse gas is primarily responsible for the enhanced greenhouse effect due to human activities?

Carbon dioxide (CO2)

3. What is the key difference between grampositive and gram-negative bacteria based on their cell wall structure?

Gram-positive bacteria have a thick peptidoglycan layer, while gram-negative bacteria have a thin peptidoglycan layer and an outer membrane.

4. Which of the following is a key characteristic of the cell wall of gram-negative bacteria?

It has an outer membrane and a thinner peptidoglycan layer.

5. Which of the following best describes the mechanism of nucleophilic addition?

A nucleophile attacks a carbonyl carbon, forming a tetrahedral intermediate before adding to the molecule

6. In the reaction of an aldehyde with a Grignard reagent (RMgX), the Grignard reagent acts as the

. Nucleophile

A 1 kg block of aluminum is heated from 25 °C to 50 °C. The specific heat capacity of aluminum is 418 J/kgK. How much heat is required?

10,450 J

In the titration of a weak acid with a strong base, what causes the pH to rise significantly after the equivalence point?

The excess OH from the strong base increases the pH

Why does the pH increase slowly in the initial stages of a titration between a weak acid and a strong base?

b. The weak acid does not dissociate completely, so fewer H+ ions are available

10. What is the primary purpose of the cold lime process in water treatment?

c. To soften hard water by removing calcium and magnesium ions

11. Which of the following is a key chemical used in the cold lime process for softening water?

b. Calcium hydroxide

12. What is the primary purpose of an equalization pond in wastewater treatment?

c. To store and stabilize fluctuating flows of wastewater before treatment

13. Which of the following is NOT a primary function of an equalization pond in wastewater treatment? a. To smoothen variations in wastewater flow

To provide long-term storage for treated wastewater

The Clausius-Clapeyron equation describes the relationship between the vapor pressure of a substance and its temperature. What does the slope of the vapor pressure curve represent?

The enthalpy of vaporization

15. Which of the following factors does NOT directly affect the slope of the vapor pressure curve according to the Clausius-Clapeyron equation?

d. Molecular weight of a substance

16. A solution has an osmotic pressure of 20 atm at 298 K. What is the mass percent of NaCl in the solution, given that the density of the solution is 1.2 g/mL and the molar mass of NaCl is 58.5 g/mol?

a. 2%

17. The resistivity of a material typically increases with an increase in temperature. This behavior is most commonly observed in

a. Conductors

18. In semiconductors, as temperature increases, the resistivity

b. Decreases

19. Oxidizers are substances that

Can provide oxygen to support combustion

20. The oxidizer symbol used in the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals (CLP) is represented as:

a. A flame over a circle

21. In Fischer esterification, which of the following is typically used as a catalyst?

c. Sulfuric acid

22. Why is sulfuric acid often used as a catalyst in esterification?

a. It accelerates the reaction by acting as a dehydration agent

23. In a cyclic process, the total change in the internal energy of the system is

a. Zero

24. In a cyclic process, the work done by the system is equal to

a. The heat absorbed by the system

25. If the transmittance of a sample is 10%, what is the absorbance of the sample?

d. 0.1

26. A solution of a compound absorbs light at a wavelength of 500 nm. The molar absorptivity of the compound at 500 nm is 2.5 L/mol-cm, and the concentration of the solution is 0.1 M, and the path length is 1 cm. What is the absorbance of the solution?

a. 0.25

27. A solution has a concentration of 0.1 M and a molar absorptivity of 1.5 L/mol-cm. The absorbance at a 2 cm path length is 0.3. If the concentration is doubled, what will the new absorbance be?

a. 0.6

28. Which of the following methods is considered the most economical for producing aluminum matrix composites (AMCs)?

b. Stir casting

29. Which of the following factors has the most significant impact on the production cost of aluminum matrix composites?

Method of casting

30. What is the primary purpose of adding carbon to iron in the production of steel?

a. To increase the tensile strength and hardness of the materia

31. How does carbon affect the microstructure of steel?

b. It leads to the formation of cementite and pearlite

32. A levorotatory compound

a. Rotates plane-polarized light to the right (clockwise)

33. Which of the following is true for a dextrorotatory compound?

a. It is denoted as L

34. What is the ratio of stress to strain in the elastic region of a material called?

b. Young’s modulus

35. What are the units of Young’s Modulus?

a. N/m2

36. What is the main role of volatile organic compounds (VOCs) in air pollution?

c. They contribute to the formation of groundlevel ozone and smog

37. Which of the following is a major source of volatile organic compounds (VOCs) in urban areas?

c. Motor vehicle exhaust

38. Which of the following best describes Scope 1 emissions in the context of the Greenhouse Gas (GHG) Protocol?

b. Direct emissions from owned or controlled sources

39. Which of the following is an example of Scope 1 GHG emissions?

b. Emissions from a company’s own fleet of delivery trucks

40. What does the term cis refer to in the context of geometrical isomerism?

b. two substituents are on the same side of a double bond or ring

41. Which of the following compounds exhibits cistrans isomerism?

b. 1,2-dichloroethane

42. In a body-centered cubic unit cell, where is the atom located in the unit cell?

c. The atom is located at both the center and the corners

43. In a body-centered cubic (BCC) structure, how much of an atom located at the corner of the unit cell contributes to the overall structure?

b. 1/8 atom

44. Which of the following is a colligative property that decreases the temperature at which a solution freezes compared to the pure solvent?

b. Freezing point depression

45. What is the role of the Van’t Hoff factor (i) in the freezing point depression formula?

b. It accounts for the number of solute particles in solution due to dissociation

46. What is hybridization in chemistry?

c. The mixing of atomic orbitals to form new, identical hybrid orbitals

47. What is the molecular geometry around the oxygen atom in dimethyl ether?

b. Bent

48. What is the standard enthalpy of formation of an element in its most stable form?

a. Zero

49. The standard enthalpy change of a reaction can be calculated using

a. Hess’ law

50. If the standard enthalpy of formation of a compound is negative, what does this indicate?

a. The reaction is exothermic

51. Given the following standard enthalpy of formation values:

ΔHf° of CO2 (g) = -393.5 kJ/mol

ΔHf° of H2O (l) = -285.8 kJ/mol

ΔHf° of C6H12O6 (s) = -1273.3 kJ/mol

Calculate the standard enthalpy change for the following reaction: C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l)

a. -2802.5 kJ

52. Which of the following is the major consideration that influences the rate of electron oxidation in a chemical reaction?

d. The ionization potential of the electron donor

53. What role does temperature play in the rate of electron oxidation reactions?

c. Higher temperature generally increases the rate of oxidatio

55. What is the result of a silent mutation in DNA?

c. The mutation does not change the amino acid sequence of the protein

56. Which of the following crystal lattice structures is considered the most stable for ionic compounds?

b. Face-centered cubic

57. In which type of crystal lattice structure do ions arrange themselves in a repeating pattern that minimizes repulsion and maximizes attraction?

c. Close-packed lattice

58. Why does the pH of a weak acid increase when its concentration is decreased?

b. The concentration of hydrogen ions decreases

59. What is the relationship between the acid dissociation constant (KA) and the pH rise in a weak acid solution?

b. Lower KA values lead to a larger pH rise

60. What is DNA synthesis?

c. The process of copying DNA to produce identical strands

61. What is the function of DNA helicase during DNA replication?

b. It unwinds the double-stranded DNA

62. Which enzyme is responsible for sealing nicks (gaps) in the sugar-phosphate backbone of DNA during replication and repair?

c. DNA ligase

63. Which molecule brings amino acids to the ribosome during translation of mRNA?

c. tRNA

64. The equivalence point in a titration is defined as

c. The point at which the number of moles of acid equals the number of moles of base

65. At the equivalence point in an acid-base titration,

c. The reactants are present in stoichiometric amounts

66. What is chlorine demand in water treatment?

b. The amount of chlorine that reacts with impurities and is not available as residual

67. Which of the following formulas is used to calculate chlorine demand in water treatment?

a. Chlorine demand = total chlorine – free chlorine

68. What is the first step in properly managing hazardous chemical waste?

c. Identifying and labeling the waste correctly

69. What is the most appropriate method for disposing of hazardous chemical waste in a laboratory?

b. Storing it in sealed containers for authorized disposal

70. On a stress-strain curve, the yield strength is defined as

b. The point where permanent deformation begins

71. Where on the stress-strain curve is the yield strength point typically located?

b. Just before the curve flattens or shows a noticeable change in slope

72. What are stereoisomers?

c. Isomers with the same molecular formula and atom connectivity but different spatial arrangements

73. A compound has 3 chiral centers. Under what condition might it have fewer than 8 stereoisomers?

c. If the molecule has internal symmetry (meso compounds)

74. What does the coordination number in an ionic crystal refer to?

c. The number of oppositely charged ions surrounding a given ion

75. How does a higher coordination number affect the stability of an ionic structure?

b. It increases the stability due to stronger electrostatic attraction

76. What is the molarity of a solution prepared by dissolving 5.84 g of NaCl (molar mass= 58.44 g/mol) in 500 mL of water?

c. 0.2 M

77. How many grams of KOH (molar mass = 56.1 g/mol) are needed to prepare 250 mL of a 0.2 M KOH solution?

a. 2.81 g

78. How many milliliters of 6 M H2SO4 must be diluted to make 500 mL of 1.5 M solution?

b. 125 mL

79. You mix 100 mL of 0.2 M NaCl with 150 mL of 0.1 M NaCl. What is the final concentration?

b. 0.14 M

80. Where are filamentous bacteria like Actinobacteria most commonly found?

c. In soil environments

81. Which of the following is a well-known genus of filamentous bacteria involved in antibiotic production?

c. Streptomyces

82. In an environmental study, the concentration of a contaminant is measured to be 800 ppm at 2 cm from the source. Assuming the concentration decreases inversely with the square of the distance from the source, what is the approximate concentration at 6 cm?

a. 89 ppm

83. What is the gravimetric factor used for in gravimetric analysis?

b. To convert the mass of a weighed compound to the mass of the analyte

84. In a gravimetric analysis, 0.5 g of AgCl (molar mass = 143.32 g/mol) is obtained. What is the mass of Cl- present? (molar mass of Cl = 35.45 g/mol)

a. 0.123 g

85. What is the precipitate formed when equal amounts of BaCl2 and Na2SO4 are mixed in aqueous solution?

b. BaSO4

88. What is the primary purpose of restriction enzymes in DNA fingerprinting?

b. To cut the DNA into specific fragments

89. Why is PM 2.5 more hazardous to human health than PM 10?

b. PM 2.5 can penetrate deeper into the lungs and bloodstream

90. Which of the following health conditions is PM 2.5 more likely to cause compared to PM 10?

b. Chronic respiratory diseases like asthma and bronchitis

91. If 50 mL of 0.1 M NaOH is used in excess to neutralize a sample, and after the reaction, 20 mL of 0.1 M HCl is required to neutralize the excess NaOH, what is the number of moles of NaOH that reacted with the sample?

d. 0.003 moles

92. In a back titration involving precipitation of AgCl from a sample containing chloride ions, 50 mL of an excess 0.1 M AgNO3 solution is added. After the AgCl precipitate is filtered, the excess AgNO3 is titrated with 0.05 M NaSCN solution. If it takes 40 mL of NaSCN to reach the endpoint, how many moles of chloride ions are in the sample?

d. 0.003 moles

93. According to Beer-Lambert Law, what happens to the absorbance of a solution if the concentration of the absorbing species is doubled?

a. The absorbance doubles

94. Why does the absorbance increase linearly with concentration, assuming Beer-Lambert Law holds?

b. Because more solute particles absorb more light proportionally

95. A solution has an absorbance (A) of 0.3 at a certain wavelength. What is the percent transmittance (% T) of the solution?

a. 50%

96. What is transmittance in the context of spectrophotometry?

c. The ratio of transmitted light to incident light

97. If the incident light is 100 units and the transmitted light is 30 units, what is the absorbance?

a. 0.52

98. For the reaction 2A ↔ 3B, the chemical potential of substance A is 15 kJ/mol. Assuming the system is at equilibrium, what is the chemical potential of B?

a. 10 kJ/mol

99. Which has the highest heat of hydrogenation?

a. Ethene

100. In what year was the first Bose-Einstein Condensate (BEC) successfully created in a laboratory, and which element was used?

a. 1995 – Rubidium (Rb)

101. What type of bonding is present in the diamond structure?

b. Covalent bonding

102. How many atoms are there in a unit cell of the diamond structure?

d. 8

103. Why is hydrocarbon density important in the petroleum industry?

b. It helps classify crude oil and fuels