Showing pages 1 to 2 of 5 pages
Chemistry Final ExamVersion 4/7/15Name:Student number:Directions:It is important that you provide answers in your own words. Please focus only oninformation from the text/eBook to create your own solutions.Please do not use direct informationfrom an outside source (especially copying and pasting from an “answer” website). Use of directinformation from an outside sourceis against school policy.All answers will be checked for plagiarism.Instances of plagiarismcan resultin probation or possible dismissal from the school.Please be sure to follow all guidelines (number of sentences/showing all calculations) and to provide thecorrect 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 (⁰C)Pressure (mm of Hg)10726207504080070880100960150???Fill in the missing data point. Show all calculations leading to an answer.P1/T1 = P2/T2P2 = P1T2 / T1P2 = 960 mm Hg x 423K / 373KP2 = 1090 mm Hg2.You are given a clear solution of KNO3. Using 3 – 4 sentences (in your own words) explain howyou would determine if the solution is unsaturated, saturated or supersaturated.If you add more KNO3 and the solution is saturated or supersaturated the added salt will not dissolveand precipitate. If the solution is saturated or supersaturated some salt will precipitate. If the solution issupersaturated, the solution will induce salt precipitation by shaking it. If the solution is unsaturated thesalt will vanish.3.Explain why gasoline will not dissolve in water.No gasoline will not dissolve with water because it is an oil product and do not blend with water.
4.Explain in 3 – 4 sentences (in your own words) how perspiration helps keep you cool on a hotday.Due to dissolution, perspiration on your skin keeps you cool. It takes thermal energy to change fluid intoa gas. Therefore, it’s on your skin, the easiest way to transfer heat is conduction from your skin to thefluid. The skin cools down, the liquid turns to a gas, and floats away.5.You have two sealed jars of water at the same temperature. In the first jar there is a largeamount of water. In the second jar there is a small amount of water. Using 3 -4 sentencesexplain how the vapor pressure of water in the first jar compares with the vapor pressure ofwater in the second jar.6.Using 3 – 4 sentences explain (in your own words) why water expands when it freezes?Water molecules tend to stick together to launch what are called hydrogen bonds. Therefore, Becauseof the shape of the molecule, the process water molecules tend to be prone together is very openformation. The oxygen atom is negative, and the hydrogens are positively charged. That means, there’squite a lot of extra empty space. When water freezes it allow to leave energy because lots of extrachains can be made which take up more space.7.Using your knowledge of colligative properties explain whether sodium chloride or calciumchloride would be a more effective substance to melt the ice on a slick sidewalk. Use 3 – 4sentences in your explanation.Because the boiling point is higher, calcium chloride releases heat making the ice melt fast than thesodium chloride.It would be more effective to use CaCl2 for the melting of ice because NaCl separateinto two particles and CaCl2 into three.8.When a 2.5 mol of sugar (C12H22O11) are added to a certain amount of water the boiling point israised by 1 Celsius degree. If 2.5 mol of aluminum nitrate is added to the same amount ofwater, by how much will the boiling point be changed? Show all calculations leading to youranswer OR use 3 – 4 sentences to explain your answer.