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Study guide for Honors Chemistry Semester 1 Final For additional resources please refer to the Moodle site or ( Brooks Chem Website ) It is suggested that you also review previous assignments, quizzes, and tests, as well as class notes. The final exam will be cumulative and will be worth approximately 10% of your grade. This semester, you have already demonstrated growth in your skills as a scientist, including your ability to design investigations to answer relevant questions, collect data, analyze data, use scientific models, and solve problems and make explanations related to the natural and designed world. We hope that preparing for the final will help you consolidate and demonstrate again these skills. The most effective way to prepare for the final is to practice, practice, and practice. If you complete all of the questions in this guide (beginning on the next page), find other related problems, or, better, make up your own problems and share them with classmates. The following are the summative goals that will be assessed on this exam. See each unit’s Continuous Progress Report (CPR) for checkpoints related to each summative goal. Unit 1: Precision, conservation of mass, and BBs Goal 1: I can explain what I observe with regards to mass and volume with a simple model of matter consisting of incredibly small, unobservable BB-like particles. Goal 2: I can collect data with precision, manipulate the data to make a histogram and simple mathematical models on a scatterplot, and use the data as evidence to draw conclusions about matter. Goal 3: Through my own scientific explanations, I can make sense of linear relationships between two variables related to amounts and properties of matter. I can use these relationships to determine an unknown variable when given the linear relationship and the value of the other variable in that relationship, using correct units. Unit 2: Energy and Matter Goal 1: I can explain and interpret the relationship between pressure, temperature, and volume of a gas mathematically and graphically. Goal 2: I can use and construct particle models to explain the behavior of matter in various states and temperatures. Goal 3: Using evidence, I can construct an explanation for the relationship between movement of particles and temperature. Unit 3: Energy and Kinetic Molecular Theory Goal 1: Using ideas about energy and particle models of matter, I can explain my own observations or written descriptions involving the heating of substances and phase changes. Goal 2: Using ideas about energy and LOL diagrams, I can explain my own observations, written descriptions, and/or heating/cooling curves involving the heating of substances and phases changes. Goal 3: I can interpret the physical meaning of the heat of fusion (Hf), heat of vaporization (HV), and heat capacity c of a substance, and use these as factors to solve problems for various substances involving energy absorption and release, the mass of a substance, phase changes, and temperature changes. 1. For the following situations, draw before/after particle diagrams that reflect the average observed change-in-mass. a. Salt is added to water. The average observed change-in-mass is close to 0.00 grams b. Water melts. The average observed change-in-mass is close to 0.00 grams c. Alka-Seltzer is added to water. The average observed change-in-mass is negative 0.30 grams. d. Steel wool is burned. The average observed change-in-mass is positive 0.40 grams. 2. Describe why parts c & d above do not violate the conservation of mass even though there was an observed change of mass. 3. Record the value and units of the following measurements with the maximum possible precision allowed by the instrument. Write number of significant figures of each measurement. All measurements are in centimeters (cm). measurement: ________ sig figs: ________ measurement: ________ sig figs: ________ 4. Round off to the indicated number of significant figures. a. 808.57 to 4 SF's _________________________ b. 808.57 to 3 SF's _________________________ c. 808.57 to 2 SF's _________________________ 5. Perform the following operations, expressing your answers to the proper number of significant figures. Write the calculator answer first, then the rounded answer. Calculator Answer a. 8.08 x 45.23 Answer Rounded to sf’s _______________________ _________________ b. 14.2003 + 3.4 _______________________ _________________ 6. Use the factor-label method to make the following conversions (be sure to keep the appropriate number of SF’s) a. 840 mL x __________________ =____________________ liters b. 2.5 x 10 -4 g x ______________________ = ______________ mg c. 1.52 x 10 8 mm x__________________ x______________ = ____________km 7. The densities of two liquids, Liquid A and Liquid B, are measured and compared. Liquid A has more density than Liquid B. Draw and label particle diagrams of each liquid that are consistent with what you know about their densities and states of matter. Do this in two different ways for extra credit. 8. A student measured the mass and volume of various samples of silver and plotted it on the graph below. Find the equation for the line of this graph and using this determines the density of silver, using correct units. 9. Using the equation from the line above, determine the mass of a 50 cm3 sample of silver. Determine the volume of a 3,000 gram sample of silver. 10. The density of gold is 19.30 g/cm3. What will take up more space- 15 grams of silver or 15 grams of gold? 11. Explain why both silver and gold sink in water, by comparing densities. 12. A sealed container is heated from 16°C to 79°C. If the original pressure was 1.2atm, what will the new pressure be at 79°C? 13. A chemical reaction must be performed at 700mmHg. The scientists performs the experiment at 58°C, 30 units of particles, and a volume of 2.45L. Before running the experiment a second time, the scientists adds 20 more units of particles and decreases the temperature to 45°C. What will the new volume be? 14. Why must temperature be converted into Kelvin before being used in Gas Laws? 15. Sketch the relationship between pressure and volume. What kind of mathematical relationship is this? Why does this make sense in light of Kinetic Molecular Theory? 16. Sketch the relationship between pressure and temperature. What kind of mathematical relationship is this? Why does this make sense in light of Kinetic Molecular Theory? 17. Explain why mercury or alcohol are used as the fluid in thermometers instead of water or a colored (visible) gas like chlorine. 18. For the barometer pictured, P Room is 760 mmHg. What is the pressure inside of the chamber? 19. If a room pressure changed and the heights of the fluid read 150 and 116, what would be the new PRoom? (assume the pressure inside of the chamber stays the same). 20. Explain why mercury is used as the fluid in barometers instead of water. 21. At the particle level, diagram the diffusion of dye in cold water and compare this to the diffusion in dye in hot water. 22. Diagram the processes of melting and condensation from the particle level. 23. Distinguish between heat (or thermal energy) and temperature. 24. Draw a cooling curve for water, imagining a scenario where water vapor is placed in a freezer for several days. Identify the sections that represent condensing and freezing. 25. What form of energy is decreasing in the water as freezing and condensing are happening? Thermal energy? Phase energy? Chemical energy? All? Neither? Some? 26. Identify the section of the cooling curve that represents the cooling of liquid water. How much energy leaves 5 grams of water after it is cooled by 5 degrees C? How much energy leaves 10 grams of water after it is cooled by 5 degrees C? 10 degrees C? 27. What would release more energy: 5 grams of water cooled by 5 degrees C or 5 grams of gold cooled by 5 degrees C? 5 grams of liquid water cooled by 5 degrees C or 5 grams of ice cooled by 5 degrees C? 28. What happens to the surroundings of the water throughout the entire cooling process. Why? 29. Explain how the conservation of energy applies to your answer to question 27. 30. Energy is added using a Bunsen burner to ice at -3°C to melt it and raise the temperature of the water to 25°C. a. Compare the particles of the initial state (ice) and the final state (water). Include motion, arrangement, and density. b. Identify the method of energy transfer in this situation. 31. Complete the following LOL diagram: 32. Make up your own scenario that involves changes in both thermal and phase energy of a substance. Describe the scenario and draw an LOL diagram to represent it. 33. How much energy is required to boil 50 grams of 100-degree C water? 34. How much energy is required to melt a 30 gram block of ice and raise the temperature of the water by 50 degrees C? 35. What would be the final temperature of a block of ice that starts at -25 C and has 40 kJ of energy added to it by heating? 36. What would be the final temperature of a block of ice that starts at -25 C and has 40 kJ of energy added to it by radiation? 37. Make up your own quantitative energy transfer problem that involves at least two portions of a heating or cooling curve. 38. Solve your problem. 39. Solve a classmates’ problem 40. Name three things you learned in chemistry class that are not represented on this study guide.