1 Sam is studying the effect of temperature on reaction rate. He knows that increasing temperature increases the rate of reaction. Why does this happen? A Because more molecules have energy greater than activation energy B Because the enthalpy change becomes more negative C Because the catalyst becomes more active D Because the bond dissociation energy decreases
2 Fatima is studying endothermic reactions. She knows that photosynthesis is an endothermic process. What happens to the enthalpy (ΔH) in an endothermic reaction? A ΔH is negative B ΔH is positive C ΔH is zero D ΔH is undefined
4 George is learning the rules for assigning oxidation states. He knows that the oxidation state of an element in its elemental form is zero. What is the oxidation state of chlorine in Cl2? A 0 B -1 C +1 D -2
5 Waleed is learning about oxidation and reduction in terms of electron transfer. He knows that a substance that loses electrons is oxidized. In the reaction: Fe + CuSO4 → FeSO4 + Cu, which substance loses electrons? A Fe B CuSO4 C FeSO4 D Cu
7 Julia is studying exothermic reactions. She knows that neutralization reactions are exothermic. What is observed when an acid reacts with a base? A Temperature decreases B Temperature increases C Temperature remains constant D No reaction occurs
8 George is studying bond formation and bond dissociation. He knows that energy is released when bonds are formed and energy is absorbed when bonds are broken. What is the term for the energy required to break a bond? A Bond formation energy B Bond dissociation energy C Activation energy D Enthalpy change
9 Usman is learning about oxidation and reduction in terms of electron transfer. He knows that in a redox reaction, one substance is oxidized and another is reduced. In the reaction: 2Na + Cl2 → 2NaCl, which substance is oxidized? A Na B Cl2 C NaCl D Both Na and Cl2
11 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
12 Samir is studying the prevention of corrosion by coating with a thin layer of another metal. He learns that galvanizing is one such method. What metal is used in galvanizing to coat iron? A Tin B Chromium C Zinc D Nickel
13 The main purpose of electroplating is to: A Increase weight B Prevent corrosion and enhance appearance C Reduce conductivity D Increase rusting
16 A catalyst works by: A Increasing enthalpy B Decreasing activation energy C Increasing temperature D Changing products
18 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
19 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
20 Waseem is studying endothermic reactions. He knows that some reactions absorb heat from the surroundings. Which of the following is an example of an endothermic reaction? A Combustion of propane B Photosynthesis C Respiration D Rusting of iron
21 Fatima is studying oxidation states. She learns that oxidation state is the charge an atom would have if all bonds were ionic. What is the oxidation state of oxygen in most compounds? A 0 B +1 C -2 D +2
22 Waleed is determining the oxidation number of an atom in a compound. He wants to find the oxidation state of chromium in K2Cr2O7. Given K is +1 and O is -2, what is the oxidation state of Cr? A +3 B +6 C +4 D +7
24 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
25 Ahmed is studying the enthalpy of reaction. He determines that the reaction A → B has ΔH = +100 kJ. What type of reaction is this? A Exothermic B Endothermic C Thermoneutral D Spontaneous