1 : What are the products of anaerobic respiration?
1 : ATP + CO₂+H₂O
2 : CO₂ + H₂O
3 : ATP + Ethanol + H₂O
4 : 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?
1 : By collisions between the molecules
2 : From sunlight
3 : From the surrounding
4 : By collisions of the molecules with the walls of the container.
3 : Which of the following reactions has the least value of activation energy?
1 : H2(g) + 1/2O2→ H2O
2 : C+O2 → CO2
3 : NaCl (aq) +AgNo3 → AgCl(s) + NaNO3(aq)
4 : H2 + l 2(s) → 2HI(g)
4 : What does it show when a chemical reaction is exothermic?
1 : it shows the bonds which break are weaker than those are formed.
2 : It shows the bond which break are stronger than those are formed.
3 : Exothermic nature of the reaction is not concerned with bond formation or bond breakage
4 : It shows that the reactants are more stable than the products.
5 : Formation of which hydrogen halide from the elements is an endothermic reaction?
1 : HCl
2 : HF
3 : HBr
4 : 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
1 : -102Kj
2 : +102KJ
3 : +350kJ
4 : +394kJ
7 : Why does the following exothermic reaction not occur? C (Diamon →C (Graphite) ΔH= -3kJ mol
1 : Structure of diamond is more stable than that of graphite.
2 : Diamond has strong covalent bonds than does the graphite.
3 : The change from diamond to graphite has high activation energy
4 : 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?
1 : Energy is always absorbed
2 : Energy is always released
3 : Energy can either be absorbed or released
4 : Energy is neither absorbed nor released
9 : In an exothermic reaction, the system
1 : Absorbs energy
2 : Releases energy
3 : Does not change in energy
4 : Requires activation energy to slow down.
10 : What happens in an endothermic reaction?
1 : Energy is released
2 : The system gains energy
3 : The system loses energy
4 : No energy change occurs
11 : The heat energy released in an exothermic reaction is stored as
1 : Kinetic energy
2 : Potential energy
3 : Chemical energy
4 : Thermal energy
12 : Which of the following does NOT describe an exothermic reaction? 13.
1 : Combustion
2 : Freezing of water
3 : Photosynthesis
4 : Neutralization of an acid with a base
13 : In an exothermic reaction, energy is
1 : Absorbed from the surroundings
2 : Released into the surroundings
3 : Stored within the reactants
4 : unchanged
14 : When NaOH and HCI are mixed, the temperature increases. The reaction is:
1 : Endothermic with a positive enthalpy change.
2 : Endothermic with a negative enthalpy change.
3 : Exothermic with a positive enthalpy change
4 : 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?
1 : CH4→C+2H2
2 : CH4 → C+2H2
3 : CH4→C+4H
4 : CH4→CH+H
16 : The heat energy released during an exothermic reaction is
1 : Used to form products
2 : Absorbed by the surroundings
3 : Converted into work
4 : Lost to the environment
17 : Enthalpy change can be calculated using which of the following formulas?
1 : AH-Energy of reactants-Energy of products
2 : AH=Energy of products-Energy of reactants
3 : AH-Energy of bonds broken-Energy of bonds formed
18 : Which of the following is an example of an exothermic reaction?
1 : Combustion of wood
2 : Melting of ice
3 : Photosynthesis
4 : Dissolving salt in water
19 : Which of these is an example of an endothermic reaction?
1 : Freezing of water
2 : Photosynthesis
3 : Burning of coal
4 : Condensation of steam
20 : Which of the following is true for an endothermic reaction?
1 : Energy is released into the surroundings
2 : Energy is absorbed from the surroundings
3 : The products have lower energy than the reactants
4 : The reaction is spontaneous
21 : The activation energy of a reaction is
1 : The energy required to start the reaction
2 : The energy required to break bonds
3 : The energy released by the reaction
4 : The energy required to form new bonds
22 : The enthalpy change for a reaction is calculated as
1 : Reactants' bond energy - Products' bond energy
2 : Products' bond energy Reactants' bond energy
3 : Reactants' temperature Products temperature
4 : Products' pressure-Reactants pressure
23 : If the enthalpy change of a reaction is negative, the reaction is
1 : Endothermic
2 : Exothermic
3 : At equilibrium
4 : Spontaneous
24 : Which of the following is the correct sequence of stages in aerobic respiration?
1 : Glycolysis→ Electron Transport Chain→ Krebs Cycle
2 : Glycolysis →Krebs Cycle → Electron Transport Chain
3 : Glycolysis → Photosynthesis Electron Transport Chain
4 : Glycolysis →Fermentation→ Electron Transport Chain
25 : What is the main difference between aerobic and anaerobic respiration?
1 : Aerobic respiration uses oxygen, while anaerobic respiration does not
2 : Anaerobic respiration occurs only in animals, while aerobic respiration occurs in plants
