1 : What are the products of anaerobic respiration?
A : ATP + CO₂+H₂O
B : CO₂ + H₂O
C : ATP + Ethanol + H₂O
D : Ethanol + H₂O
2 : The following reaction is an exothermic reaction H2 + C12 → Sunlight 2HCI From where does the energy come to break the bond of H2 and CI2?
A : By collisions between the molecules
B : From sunlight
C : From the surrounding
D : By collisions of the molecules with the walls of the container.
3 : Which of the following reactions has the least value of activation energy?
A : H2(g) + 1/2O2→ H2O
B : C+O2 → CO2
C : NaCl (aq) +AgNo3 → AgCl(s) + NaNO3(aq)
D : H2 + l 2(s) → 2HI(g)
4 : What does it show when a chemical reaction is exothermic?
A : it shows the bonds which break are weaker than those are formed.
B : It shows the bond which break are stronger than those are formed.
C : Exothermic nature of the reaction is not concerned with bond formation or bond breakage
D : It shows that the reactants are more stable than the products.
5 : Formation of which hydrogen halide from the elements is an endothermic reaction?
A : HCl
B : HF
C : HBr
D : HI
6 : The average bond energies for 0-0 and 0-0 are 146 and 496 KJ mol"1 respectively. Find t enthalpy in kl for the following reaction? H--------O--------O--------H→H----------O--------H+1/2 O O
A : -102Kj
B : +102KJ
C : +350kJ
D : +394kJ
7 : Why does the following exothermic reaction not occur? C (Diamon →C (Graphite) ΔH= -3kJ mol
A : Structure of diamond is more stable than that of graphite.
B : Diamond has strong covalent bonds than does the graphite.
C : The change from diamond to graphite has high activation energy
D : Density of graphite is less than that of diamond.
8 : Important MCQ's Energetic, system and surroundings Which of the following is true about energy in a chemical reaction?
A : Energy is always absorbed
B : Energy is always released
C : Energy can either be absorbed or released
D : Energy is neither absorbed nor released
9 : In an exothermic reaction, the system
A : Absorbs energy
B : Releases energy
C : Does not change in energy
D : Requires activation energy to slow down.
10 : What happens in an endothermic reaction?
A : Energy is released
B : The system gains energy
C : The system loses energy
D : No energy change occurs
11 : The heat energy released in an exothermic reaction is stored as
A : Kinetic energy
B : Potential energy
C : Chemical energy
D : Thermal energy
12 : Which of the following does NOT describe an exothermic reaction? 13.
A : Combustion
B : Freezing of water
C : Photosynthesis
D : Neutralization of an acid with a base
13 : In an exothermic reaction, energy is
A : Absorbed from the surroundings
B : Released into the surroundings
C : Stored within the reactants
D : unchanged
14 : When NaOH and HCI are mixed, the temperature increases. The reaction is:
A : Endothermic with a positive enthalpy change.
B : Endothermic with a negative enthalpy change.
C : Exothermic with a positive enthalpy change
D : Exothermic with a negative enthalpy change
15 : (vii) The average bond dissociation energy for the C-H bond is 412 kJ/mol". Which of the following process will have enthalpy change close to 412 kJ/mol¹?
A : CH4→C+2H2
B : CH4 → C+2H2
C : CH4→C+4H
D : CH4→CH+H
16 : The heat energy released during an exothermic reaction is
A : Used to form products
B : Absorbed by the surroundings
C : Converted into work
D : Lost to the environment
17 : Enthalpy change can be calculated using which of the following formulas?
A : AH-Energy of reactants-Energy of products
B : AH=Energy of products-Energy of reactants
C : AH-Energy of bonds broken-Energy of bonds formed
18 : Which of the following is an example of an exothermic reaction?
A : Combustion of wood
B : Melting of ice
C : Photosynthesis
D : Dissolving salt in water
19 : Which of these is an example of an endothermic reaction?
A : Freezing of water
B : Photosynthesis
C : Burning of coal
D : Condensation of steam
20 : Which of the following is true for an endothermic reaction?
A : Energy is released into the surroundings
B : Energy is absorbed from the surroundings
C : The products have lower energy than the reactants
D : The reaction is spontaneous
21 : The activation energy of a reaction is
A : The energy required to start the reaction
B : The energy required to break bonds
C : The energy released by the reaction
D : The energy required to form new bonds
22 : The enthalpy change for a reaction is calculated as
A : Reactants' bond energy - Products' bond energy
B : Products' bond energy Reactants' bond energy
C : Reactants' temperature Products temperature
D : Products' pressure-Reactants pressure
23 : If the enthalpy change of a reaction is negative, the reaction is
A : Endothermic
B : Exothermic
C : At equilibrium
D : Spontaneous
24 : Which of the following is the correct sequence of stages in aerobic respiration?
A : Glycolysis→ Electron Transport Chain→ Krebs Cycle
B : Glycolysis →Krebs Cycle → Electron Transport Chain
C : Glycolysis → Photosynthesis Electron Transport Chain
D : Glycolysis →Fermentation→ Electron Transport Chain
25 : What is the main difference between aerobic and anaerobic respiration?
A : Aerobic respiration uses oxygen, while anaerobic respiration does not
B : Anaerobic respiration occurs only in animals, while aerobic respiration occurs in plants
C : Aerobic respiration produces ethanol, while anaerobic respiration produces lactic acid
D : Both processes occur in the absence of oxygen
26 : What is the main product of anaerobic respiration in muscle cells?
A : Oxygen
B : Lactic acid
C : Water
D : Carbon dioxide
27 : Which of the following is a product of anaerobic respiration in yeast?
A : Lactic acid
B : Ethanol and carbon dioxide
C : Water and carbon dioxide
D : Oxygen
28 : Which process occurs in the absence of oxygen?
A : Anaerobic respiration
B : Aerobic respiration
C : Both aerobic and anaerobic respiration
D : Photosynthesis
29 : The unit of enthalpy change is
A : Joules (J)
B : Moles (mol)
C : Kilojoules per mole (kJ/mol)
D : Kelvin (K)
30 : What is produced during aerobic respiration?
A : Lactic acid
B : Carbon dioxide and water
C : Ethanol
D : glucose
31 : What is the primary difference between aerobic and anaerobic respiration?
A : Oxygen is used in anaerobic respiration
B : Oxygen is used in aerobic respiration
C : Carbon dioxide is produced in anaerobic respiration
D : Both types of respiration occur in plant cells.
32 : In aerobic respiration, how many molecules of ATP are produced from one molecule of glucose?
A : 36-38 ATP molecules
B : 2 ATP molecules.
C : 18 ATP molecules
D : 1 ATP molecule
33 : The process of breaking down glucose to release energy in the presence of oxygen is called
A : Photosynthesis
B : Aerobic respiration
C : Fermentation
D : Glycolysis
34 : Which of the following statements about anaerobic respiration is correct?
A : It requires oxygen
B : it produces carbon dioxide and water
C : It occurs without oxygen
D : it produces more ATP than aerobic respiration.
35 : Which of the following is NOT a characteristic of aerobic respiration?
A : It requires oxygen
B : It produces ethanol as a byproduct
C : It occurs in the mitochondria
D : it produces a large amount of ATP.
36 : The process of anaerobic respiration in yeast produces
A : Water and carbon dioxide
B : Ethanol and carbon dioxide
C : Oxygen and lactic acid
D : Oxygen and glucose
37 : What is the surrounding in a chemical reaction?
A : The reactants involved
B : Everything outside the system
C : The products formed
D : The energy released during the reaction
38 : Which term describes the heat content of a system?
A : Temperature
B : Internal energy
C : Enthalpy
D : Pressure
39 : In aerobic respiration, glucose is converted into
