Idea Transcript
Intro. to Chem and Physics
Exam 3
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Name______________________________________ Date:_________________ Part I. Math Skills. 1. Convert 0.5 decimeters to millimeters. Fill in the blanks. Step 1. Convert 0.5 decimeters to meters. 1 𝑑𝑚 = deci-‐meter = ________ 𝑚 ________ ________ × = ________ 𝑚 ________ Step 2. Convert answer from first step to millimeters. 1 𝑚𝑚 = milli-‐meter = ________ 𝑚 ________ ________ × = ________ 𝑚𝑚 ________ 2. Convert 600 centigrams to decigrams. Follow format exactly as above. Step 1. Step 2.
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Intro. to Chem and Physics
Exam 3
Zumbo
3. What is the molarity of a solution containing 0.32 moles of sodium chloride, NaCl, in 3.4 L of solution? 4. Calculate the molarity of a solution that contains 35.0 grams of barium chloride, BaCl2, dissolved in 0.45 L of solution. 5. How many moles of lithium chloride, LiCl, are dissolved in 3.00 L of a 0.200 M solution of lithium chloride? 6. How many grams of calcium chloride, CaCl2, are needed to prepare 0.4 L of a 1.20 M solution of calcium chloride? 7. What is the molarity of 250 mL of a solution that contains 12.5 g of dissolved zinc bromide, ZnBr2? (convert mL to L first!)
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Intro. to Chem and Physics
Exam 3
Zumbo
Bonus: A sample of oxygen gas occupies a volume of 4.02 mL at 2.5 kPa. What will its pressure be if the volume decreases to 1.5 mL? Part II. Definitions. Define each term. 1. Reactant. 2. Product. 3. Endothermic reaction. 4. Exothermic reaction. 5. Catalyst. 6. Inhibitor. 7. Enzyme.
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Intro. to Chem and Physics
Exam 3
Zumbo
8. Chemical equilibrium. 9. Le Châtelier’s principle. 10. Solute. 11. Solvent. 12. Polar compound. 13. Nonpolar compound. 14. Hydrogen bonding. 15. Solubility. 16. Concentration. 17. Unsaturated.
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Intro. to Chem and Physics
Exam 3
Zumbo
18. Saturated. 19. Supersaturated. Bonus: Define orbital OR valence electron OR polyatomic ion OR kinetic energy OR temperature OR radical. Part III. Short answers, tables and plots. 1. Identify each of the following reactions as exothermic or endothermic. CH4(s) + 2O2(g) → CO2(g) + 2H2O(l) ΔH° = -‐890 kJ 2HCl(g) → H2(g) + Cl2(g) ΔH° = 185 kJ 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l) ΔH° = -‐1169 kJ 2. Balance the following equations and indicate the type of reaction taking place (synthesis, decomposition, combustion, single-‐ displacement or double-‐displacement). a. ____ H2SO4 + ____ NaOH → ____ Na2SO4 + ____ H2O Type of reaction: ____________________ b. ____ Fe + ____ S8 →____ FeS Type of reaction: ____________________
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Intro. to Chem and Physics
c.
Exam 3
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____ KClO3 → ____ KCl + ____ O2 Type of reaction: ____________________
d. e.
____ C2H6 + ____ O2 → ____ H2O + ____ CO2 Type of reaction: ____________________ ____ Al + ____ CuCl2 → ____ AlCl3 + ____ Cu Type of reaction: ____________________
3. Which half-‐equation contains a reducing agent and which contains an oxidizing agent? a. Cu → Cu2+ + 2e– b. 2e– + 2Ag+ → 2Ag 4. Name 6 factors that affect the rate of a reaction. State how each factor affects the rate. a. • b. • c. • d. •
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Intro. to Chem and Physics
Exam 3
Zumbo
e. f.
• •
5. Consider the below reaction. The forward reaction releases energy, whereas the backward reaction absorbs energy. If the temperature of the reaction is increased, which reaction will be favored according to Le Châtelier’s principle? N2+3H2 ↔ 2NH3 ΔH° = -‐22.1 k.cal 6. Write the appropriate charges on the water molecule below, and explain why the individual H—O bonds are very polar.
7. Explain what happens when sodium chloride, NaCl, dissolves in water. Why does this occur?
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Intro. to Chem and Physics
Exam 3
Zumbo
8. Which solvent, water or carbon tetrachloride, best dissolves iodine? Why? Water is polar, while both iodine and carbon tetrachloride are not. 9. Complete the below concept map.
mixtures can be
___________
___________
which can be
also called
___________ which
___________
___________
___________
which
___________
10. How might knowledge of chemical reactions or the dissolution process be useful in everyday life?
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Intro. to Chem and Physics
Exam 3
Zumbo
Bonus: Elements can be classified into families. a. Complete the following concept map (consider part c). b. For each major family, list two defining features. c. For each major family, draw an arrow encompassing each subfamily indicating increasing reactivity d. For each subfamily, name the periodic group or groups that are represented.
elements
___________
___________
___________
___________
___________
___________
___________
___________
End of Exam Bonus: What did you find interesting from chapters 6 and 7?
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