1 Which statement about bond breaking is correct? A It releases energy B It requires energy C It has no energy change D It only occurs in exothermic reactions
2 Which statement about a closed system is correct? A It can exchange both matter and energy with surroundings. B It can exchange energy but not matter with surroundings. C It cannot exchange either matter or energy. D It can exchange matter but not energy.
3 According to Arrhenius, an acid is a substance that: A Accepts a proton B Donates a proton C Produces H+ ions in water D Produces OH- ions in water
4 Which of the following is an isolated system? A A sealed thermos flask B A cup of hot tea C A boiling pot without lid D An open beaker
5 According to the Arrhenius concept, an acid is a substance that: A Donates a proton B Accepts a proton C Produces H+ ions in water D Produces OH- ions in water
6 What is the balanced equation for aerobic respiration? A C6H12O6 + 6O2 → 6CO2 + 6H2O + energy B C6H12O6 → 2C2H5OH + 2CO2 + energy C 6CO2 + 6H2O → C6H12O6 + 6O2 D C6H12O6 + 6CO2 → 6O2 + energy
7 How does a catalyst affect the rate of reaction? A Increases activation energy B Decreases activation energy C Increases temperature D Decreases concentration
8 What is the effect of adding more reactant to a system at equilibrium? A Equilibrium shifts to the left B Equilibrium shifts to the right C Equilibrium does not change D The reaction stops
9 Which type of reaction goes to completion and does not reach equilibrium? A Reversible reaction B Irreversible reaction C Dynamic equilibrium D Physical equilibrium
10 The heat content of a system at constant pressure is called: A Entropy B Enthalpy C Internal energy D Free energy
11 Which safety rule should be followed when handling acids and bases in the laboratory? A Taste the solution to identify it B Wear safety goggles and gloves C Smell the gas directly D Store acids in open bottles
12 Which factor does NOT affect the rate of a chemical reaction? A Temperature B Concentration of reactants C Surface area of solid reactants D Enthalpy change of the reaction
13 In anaerobic respiration in yeast, glucose is converted into which products? A Carbon dioxide and water B Ethanol and carbon dioxide C Lactic acid only D Oxygen and water
14 A limitation of the Arrhenius concept is that it: A Cannot explain the basic nature of ammonia B Cannot explain acids in water C Requires a non-aqueous solvent D Only applies to strong acids
15 According to Le Chatelier's principle, adding more reactant to an equilibrium mixture will: A shift the equilibrium to the forward direction B shift the equilibrium to the backward direction C have no effect on the equilibrium D stop the reaction completely
16 Dynamic equilibrium is established only in a: A Closed system B Open system C Isolated system D Reversible system
17 Which process releases energy in a chemical reaction? A Bond breaking B Bond making C Both bond breaking and bond making D Neither bond breaking nor bond making
18 The transition state in a reaction is also known as: A Activated complex B Product C Catalyst D Intermediate
19 Which instrument is used to measure the heat change during a chemical reaction? A Thermometer B Calorimeter C Barometer D Hydrometer
20 For the reaction N2O4(g) ⇌ 2NO2(g), an increase in pressure will shift equilibrium to: A The right B The left C No shift D Stop the reaction
21 Which reaction represents neutralization? A Acid + metal → salt + hydrogen B Acid + base → salt + water C Acid + carbonate → salt + water + CO₂ D Base + metal → salt + hydrogen
22 According to the Lewis concept, an acid is a substance that: A donates a proton. B accepts a proton. C donates an electron pair. D accepts an electron pair.
23 In anaerobic respiration in yeast, glucose is converted into: A Carbon dioxide and water B Ethanol and carbon dioxide C Lactic acid only D Oxygen and ATP
24 Which gas is produced when a dilute acid reacts with a metal such as zinc? A Oxygen B Carbon dioxide C Hydrogen D Chlorine
25 According to Le Chatelier's principle, increasing the concentration of a reactant will: A Shift equilibrium to the left B Shift equilibrium to the right C Have no effect on equilibrium D Stop the reaction