University:
Glendale Community College
Course:
CHM151 | General Chemistry I
Academic year:

2020
Views:

426

Pages:

4
Author:

izrazitih2q

Name: Section: KEY CHM 151 Exam 3: Chapters 3 and 4 You must show all work to receive credit. Clearly mark your final answer! 1. Balancing equations when products are given a. 2CrF₅(aq) + 3H₂SO₄(aq) → 6HF(aq) + Cr₂(SO₄)₃(aq) b. 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) 2. How many hydroxide ions are present in 22.6g of aluminum hydroxide? 22.6g Al(OH)₃ × (1 mol Al(OH)₃ / 78.002g Al(OH)₃) × (3 mol OH⁻ / 1 mol Al(OH)₃) = 0.8692 mol OH⁻ 0.8692 mol OH⁻ × (6.022×10²³ ions / 1 mol) = 5.23×10²³ ions 3. List the common strong acids. Give both the name and the formula of each acid. HCl hydrochloric acid HBr hydrobromic acid HNO₃ nitric acid H₂SO₄ sulfuric acid HClO₃ chloric acid HClO₄ perchloric acid 4. Draw what the formula unit of each compound would look like if placed in its beaker of water. HNO₃ 5. A student is asked to combine sodium sulfide and hydrochloric acid solutions in a lab experiment. Complete the molecular equation with reactants and products (including phases) and balancing. Then write the complete ionic and net ionic equations for this reaction. Identify the spectator ions. Molecular: Na2S(aq) + 2HCl(aq) -> H2S(g) + 2NaCl(aq) Ionic: 2Na+(aq) + S2-(aq) + 2H+(aq) + 2Cl-(aq) -> H2S(g) + 2Na+(aq) + 2Cl-(aq) Net Ionic: S2-(aq) + 2H+(aq) -> H2S(g) 6. For the following reactions: Determine what type of reaction will occur, indicating all that apply. Combination (C), Decomposition (D), Single-replacement (SR), Combustion (B), Double-Replacement/Precipitation (P), Acid-Base Neutralization (AB), or No Reaction (NR) Predict the product(s) of the reaction. Write correct phases of the product(s). Balance the equation. Reaction Type Reactants Products C Co(s) + H2O(l) -> H2CO3(aq) NR Zn(s) + HCl(aq) -> no reaction P CuSO4(aq) + NaOH(aq) -> Cu(OH)2(s) + Na2SO4(aq) 7. Identify the oxidation number of each element in the following substances. Write each oxidation number above the element it corresponds to in the formula. a) H2CrO4 +1 +6 -2 b) AlH4 +3 -1 8. In the following equation, identify the: species being reduced. species being oxidized. reducing agent. oxidizing agent. 2Li(s) + FeCl2(aq) -> 2LiCl(aq) + Fe(s) Oxidized: Fe Reduced: Li Oxidizing agent: FeCl2 Reducing agent: Li