1 Khalid is learning about oxidizing and reducing agents. He understands that an oxidizing agent causes oxidation of another substance and is itself reduced. In the reaction: CuO + H2 → Cu + H2O, which is the oxidizing agent? A CuO B H2 C Cu D H2O
2 Qasim is learning about electroplating. He understands that electroplating is a process that uses an electric current to coat a metal with another metal. Which of the following is a common application of electroplating? A Coating iron with tin B Coating iron with zinc C Coating steel with chromium for decorative and protective purposes D Coating copper with silver
3 What is the heat of reaction? A Heat lost by surroundings B Heat gained by system C Heat change during reaction D Temperature change only
4 Quinn is studying activation energy. He knows that even exothermic reactions require an initial input of energy. What is this initial energy called? A Enthalpy change B Bond dissociation energy C Activation energy D Free energy
6 Victor is studying exothermic reactions. He knows that combustion reactions are exothermic. Which of the following is an example of a combustion reaction? A Photosynthesis B Burning of methane C Dissolving ammonium nitrate in water D Electrolysis of water
7 Which process converts electrical energy into chemical energy? A Voltaic cell B Electrolytic cell C Fuel cell D Dry cell
8 Which substance is necessary for rusting of iron? A Nitrogen B Carbon dioxide C Water and oxygen D Hydrogen
9 Which reaction has products with lower energy than reactants? A Endothermic B Physical C Exothermic D Neutral
12 Electroplating is used to: A Remove rust B Protect metals and improve appearance C Increase corrosion D Purify metals
13 Zara is studying anaerobic respiration. She knows that yeast undergoes anaerobic respiration to produce alcohol. What is the product of anaerobic respiration in yeast? A Lactic acid B Ethanol and carbon dioxide C Water and oxygen D Glucose and oxygen
14 The cathode in a galvanic cell is: A Negatively charged B Neutral C Positively charged D Insulated
15 The peak of an energy profile diagram represents: A Products B Reactants C Transition state D Catalyst
16 David is studying redox reactions in terms of transfer of oxygen. He learns that oxidation involves gain of oxygen while reduction involves loss of oxygen. In the reaction: 2Mg + O2 → 2MgO, which substance is reduced? A Mg B O2 C MgO D Both A and B
17 Ibrahim is studying polyatomic ions. He learns that the sum of oxidation states in a polyatomic ion is equal to the charge of the ion. In the sulfate ion (SO4^2-), what is the total sum of oxidation states? A 0 B +2 C -2 D +4
18 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
19 Julia is determining the oxidation number of an atom in a compound. She wants to find the oxidation state of sulfur in H2SO4. Given that H is +1 and O is -2, what is the oxidation state of S? A +2 B +4 C +6 D -2
20 Ethan is studying cathodic protection. He learns that this method is often used to protect underground pipelines. What is the principle behind cathodic protection? A The protected metal is made the anode B The protected metal is made the cathode and a more reactive metal acts as a sacrificial anode C The protected metal is coated with paint D The protected metal is alloyed with chromium
21 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
22 Fatima is learning about the formula of ionic compounds. She knows that the charges of the ions must balance. What is the formula of the ionic compound formed between aluminum (Al3+) and oxygen (O2-)? A AlO B Al2O3 C Al3O2 D AlO2
23 Ming is studying activation energy. He knows that a reaction with a high activation energy will be slow at room temperature. How can the activation energy be reduced? A By increasing temperature B By using a catalyst C By decreasing pressure D By increasing concentration
24 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
25 Ming is studying the energy changes in chemical reactions. He knows that bond formation releases energy. What is the energy change when bonds are formed? A Exothermic B Endothermic C No energy change D Energy is neither absorbed nor released
26 The energy profile of an endothermic reaction shows: A Products lower than reactants B Products higher than reactants C No energy change D Same energy level
28 Patricia is studying the energy involved in bond breaking and forming. She knows that breaking a bond requires energy and forming a bond releases energy. In an exothermic reaction, which is true? A Energy released in bond formation is greater than energy absorbed in bond breaking B Energy absorbed in bond breaking is greater than energy released in bond formation C Energy released and absorbed are equal D No bonds are broken
29 Oxidation is the process of: A Gain of electrons B Loss of electrons C Gain of neutrons D Loss of protons
30 Which of the following is an example of oxidation? A Zn → Zn2+ + 2e− B Cu2+ + 2e− → Cu C Cl2 + 2e− → 2Cl− D O2 + 4e− → 2O2−