CHEM 104 Module 2 Actual Exam Questions and Answers | 2026 | Portage Learning

Ace your CHEM 104 Module 2 exam with these actual questions and answers from 2026 (Portage Learning). Detailed solutions to boost your understanding and grades. Question 1 Identify each of the compounds below as ACID, BASE or SALT on the basis of their formula and explain your answer. (1) Cr(OH) 3 (2) HAsO 4 (3) CoCO 3 Your Answer: 1. base - contains Cr metal + OH polyatomic group 2. acid - contains H + polyatomic group (AsO ) 4 3. salt - contains Co metal + polyatomic group (CO ) 3 Question 2 For the Brønsted-Lowry acid base reactions shown below, list the stronger acid, stronger base, weaker acid and weaker base in the answer blanks provided: + - NH + H PO NH + H PO 4 2 4 3 3 4 Stronger acid: Stronger base: Weaker acid: Weaker base: Your Answer: Stronger acid: H PO 3 4 Stronger base: NH 3 + Weaker acid: NH 4 - Weaker base: H PO 2 4 Label each reaction provided as homogeneous or heterogeneous equilibrium 1. Homogeneous 2. Heterogeneous 3. Homogeneous 4. Heterogeneous 1. 2CO (g) + O2 (g) ⇌ 2CO2 (g) 2. H2 (g) + O2 (g) ⇌ H2O2 (l) 3. NaOH (aq) + HCl (aq) ⇌ NaCl (aq) + H2O (l) 4. 4Cu (s) + O2 (g) ⇌ 2Cu2O (s) 1) Define coupled equilibrium and explain how it can be used to determine K. 2) Imagine that you have mixed hydrogen, carbon, and oxygen in a laboratory setting. You determine that the following chemical equation was established at equilibrium: 1. The K value for a system involving two or more reactions that have in common one or more reactant or product species can be related to the K values of the individual reactions. 2. Reactions A and D. Reaction A would be reversed. H2 (g) + CO2 (g) ⇌ CO (g) + H2O (g) Kc = ? Using the principles of coupled equilibria, which TWO reactions from the list below could you use to solve for the Kc value of this experimentally determined reaction? A. CoO (s) + CO (g) ⇌ Co (s) + CO2 (g) B. Cu2O (s) ⇌ Cu (s) + O2 (g) C. 2Mg (s) + O2 (g) ⇌ 2MgO (s) D. CoO (s) + H2 (g) ⇌ Co (s) + H2O (g) Le Chateliers principle if an equilibrium is stressed, the system will experience a shift in response to that stress that re-establishes equilibrium Determine the formic acid concentration in a solution with [HCO2-] = 0.035 M and [OH-] = 1.8 x 10-6 M at equilibrium. The Ka of formic acid, HCO2H, is 1.8 ×10-4. Show your work and report your answer to 3 significant figures. Step 1) Find the Kb for HCO2Kb(HCO2) = Kw / HCO2H Kb(HCO2) = (1.0 x 10-14) / (1.8 x 10-4) Kb(HCO2) = 5.56 x 10-11 HCO2- (aq) + H2O (l) ⇌ HCO2H (aq) + OH- (aq) Step 2) Solve to find the formic acid concentration (concentration of HCO2H) Kb = ((HCO2H) (OH)) / (HCO2) 5.56 x 10-11 = ((HCO2H) (1.8 x 10-6)) / (0.035) HCO2H concentration = 1.08 x 10-6 M Determine the stronger acid in each of the sets below. Explain why the selected acid is the stronger of the two. 1.) H2Te and H2S 2.) NH3 and HF 1) H2Te is the stronger acid. As you move down a group the strength of the bond between the central atom and hydrogen weakens. The Te-H bond is weaker than the S-H bond meaning that H2Te is the stronger acid. 2) HF is the stronger acid. As your move to the right across a group the electronegativity of the nonmetal atom increases creating an increasingly polar bond with H. F is more electronegative than N meaning that HF is the stronger acid.