3 Sam is studying thermochemical reactions. He knows that thermochemical equations include the enthalpy change. Which of the following is a thermochemical equation? A 2H2 + O2 → 2H2O B 2H2 + O2 → 2H2O + 572 kJ C H2 + O2 → H2O D H2 + 1/2O2 → H2O
4 Nora is studying the energy changes in respiration. She knows that glucose is broken down to release energy. What is the overall energy change in aerobic respiration? A Exothermic B Endothermic C Isothermic D No energy change
5 Burning of fuel is an example of: A Endothermic reaction B Exothermic reaction C Physical change D Neutral reaction
6 Which reaction has higher activation energy? A Fast reaction B Slow reaction C Catalyzed reaction D Neutral reaction
7 Hina is studying activation energy. She knows that activation energy is the minimum energy required for a reaction to occur. How does a catalyst affect the activation energy? A Increases activation energy B Decreases activation energy C No effect on activation energy D Increases reaction temperature
8 What is meant by energy in chemistry? A Ability to do work B Ability to change color C Ability to form solids D Ability to increase mass
9 Xia is studying the concept of activation energy. She knows that an increase in temperature increases the rate of reaction. What happens to the activation energy when temperature is increased? A Activation energy increases B Activation energy decreases C Activation energy remains the same D Activation energy becomes zero
11 Which reaction has products with lower energy than reactants? A Endothermic B Physical C Exothermic D Neutral
12 Khalid is comparing aerobic and anaerobic respiration. He knows that anaerobic respiration occurs in the absence of oxygen. What is a common product of anaerobic respiration in muscles? A Ethanol B Lactic acid C Carbon dioxide D Water
13 Tina is studying respiration. She knows that respiration occurs in living organisms to release energy. Which of the following is the correct word equation for aerobic respiration? A Glucose + oxygen → carbon dioxide + water + energy B Glucose → carbon dioxide + ethanol + energy C Glucose + oxygen → carbon dioxide + ethanol D Glucose → lactic acid + energy
14 David is studying thermochemical equations. He writes the equation: C(s) + O2(g) → CO2(g) ΔH = -393.5 kJ. What does the negative ΔH indicate? A The reaction is endothermic B The reaction is exothermic C The reaction is at equilibrium D The reaction requires a catalyst
15 Rachel is studying aerobic respiration. She knows that the overall reaction is: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy. What is the energy released in this reaction in the form of? A Light B ATP C Heat only D Electrical energy
16 Heat change measured at constant pressure is: A Internal energy B Enthalpy change C Entropy D Activation energy
17 Bilal is studying a reaction where the temperature of the solution decreases. He feels the beaker and it becomes cold. Based on this observation, what type of reaction is occurring? A Exothermic B Endothermic C Combustion D Oxidation
18 Waseem is studying the energy changes in respiration. He knows that anaerobic respiration produces less ATP than aerobic respiration. How many ATP molecules are produced from one glucose molecule in anaerobic respiration? A 2 ATP B 36 ATP C 4 ATP D 18 ATP
19 What happens to surroundings in an exothermic reaction? A They cool down B They gain heat C No change D They lose mass
21 Heat of reaction depends on: A Path of reaction B Initial and final states C Speed of reaction D Color of reactants
24 Chloe is learning about the system and surroundings in chemistry. She identifies the reaction mixture as the system and everything else as the surroundings. If heat flows from the system to the surroundings, what is the sign of enthalpy change? A Positive B Negative C Zero D Cannot be determined