Chemistry Final Exam
Directions: It is important that you provide answers in your own words. Please focus only on information from the text/eBook to create your own solutions. Please do not use direct information from an outside source (especially copying and pasting from an "answer" website). Use of direct information from an outside source is against school policy. All answers will be checked for plagiarism. Instances of plagiarism can result in probation or possible dismissal from the school.
Please be sure to follow all guidelines (number of sentences/showing all calculations) and to provide the correct metric units of measure. All questions are 5 points (1 point for sentence number /units).
1. A student collected the following data for a fixed volume of gas:
|
Temperature (°C)
|
Pressure (mm of Hg)
|
|
10
|
726
|
|
20
|
750
|
|
40
|
800
|
|
70
|
880
|
|
100
|
960
|
|
150
|
???
|
Fill in the missing data point. Show all calculations leading to an answer.
2. You are given a clear solution of KNO3. Using 3 - 4 sentences (in your own words) explain how you would determine if the solution is unsaturated, saturated or supersaturated.
3. Explain why gasoline will not dissolve in water.
4. Explain in 3 - 4 sentences (in your own words) how perspiration helps keep you cool on a hot day.
5. You have two sealed jars of water at the same temperature. In the first jar there is a large amount of water. In the second jar there is a small amount of water. Using 3 -4 sentences explain how the vapor pressure of water in the first jar compares with the vapor pressure of water in the second jar.
6. Using 3 - 4 sentences explain (in your own words) why water expands when it freezes?
7. Using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. Use 3 - 4 sentences in your explanation.
8. When a 2.5 mol of sugar (C12H22O11) are added to a certain amount of water the boiling point is raised by 1 Celsius degree. If 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? Show all calculations leading to your answer OR use 3 - 4 sentences to explain your answer.
9. If 5.40 kcal of heat is added to 1.00 kg of water at 100°C, how much steam at 100°C is produced? Show all calculations leading to an answer.
10. The freezing of water at 0°C can be represented as follows:
H2O (l) ↔ H2O(s)
The density of liquid water is 1.00 g/cm3. The density of ice is 0.92 g/cm3. In 3 - 4 sentences explain why applying pressure causes ice to melt.
11. The Kw of water varies with temperature. Calculate the pH of water at 46°C with a Kw = 1.219 x 10-14. Show all calculations leading to an answer.
12. Calculate the hydroxide ion concentration of a solution with pH = 3.25. Show all calculations leading to an answer.
13. What salt results from the neutralization of phosphoric acid with potassium hydroxide?
14. What is the oxidation number of chlorine in Al(ClO4)3?
15. Which element is oxidized in the following reaction:
CuO(s) + H2 (g)à Cu(s) + H2O (l)
16. Why must the number of electrons lost equal the number of electrons gained in every redox reaction? Use 3 - 4 sentences in your own words to address this question.
17. The following unbalanced equation describes the reaction that can occur when lead (II) sulfide reacts with oxygen gas to produce lead (II) oxide and sulfur dioxide gas:
PbS + O2à PbO + SO2
Balance the equation and describe in words the electron transfer(s) that takes place.
18. What type of radiation is emitted when chromium-51 decays into manganese-51? Show the nuclear equation that leads you to this answer.
19. A radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. What was the identity of the original nucleus? Show the nuclear equation that leads you to this answer.
20. Iron-59 has a half-life of 45.1 days. How old is an iron nail if the Fe-59 content is 25% that of a new sample of iron? Show all calculations leading to a solution.