Phase Changes Exploration Worksheet

Phase Changes Worksheet Name ______________ Important Things to Know - Do Not Skip Over these 2 Sections READ and REMEMBER Kinetic Theory of Matter: ● ● ● ● ● ● Molecules are always moving. This is known as the kinetic theory of matter. We measure this kinetic energy with a thermometer as temperature. The greater the material's internal energy, the higher the temperature of that material. Heat is the energy flow between objects of different temperatures. Heat and temperature are NOT the same. Brownian motion describes how visible particles are seen moving due to invisible molecules bumping into them. Phases of Matter: Solid ● matter that has definite volume and shape. ● The molecules are packed together tightly and move slowly. Liquid ● matter that has definite volume but not shape. ● Since the molecules of a liquid are loosely packed and move with greater speed, ● a liquid can flow and spread. Gas ● matter that has indefinite volume or shape. ● Molecules of a gas are so loosely arranged and move so rapidly that they will fill their container. Phase Change Descriptions: Melting the change from ________________ to ________________. Freezing the change from _________________ to _________________. Evaporation the change from ________________ to _________________ . Condensation the change from ________________ to __________________ . Sublimation the change from _______________ to __________________ . Deposition the change from _______________ to __________________ . Fill in the phase changes in the blank provided. Phase Change Worksheet The graph was drawn from data collected as a substance was heated at a constant rate. Use the graph to answer the following questions. At point A, the beginning of observations, the substance exists in a solid state. Material in this phase has _________________ volume and _________________ shape. With each passing minute, _________________ is added to the substance. This causes the molecules of the substance to _________________ more rapidly which we detect by a ________________ rise in the substance. At point B, the temperature of the substance is __________°C. The solid begins to ________________. At point C, the substance is completely _______________ or in a _______________ state. Material in this phase has _________________ volume and ________________ shape. The energy put to the substance between minutes 5 and 9 was used to convert the substance from a __________________ to a _________________. This heat energy is called the latent heat of fusion. (An interesting fact.) Between 9 and 13 minutes, the added energy increases the ____________________ of the substance. During the time from point D to point E, the liquid is ____________________. By point E, the substance is completely in the ________________ phase. Material in this phase has __________________ volume and ___________________ shape. The energy put to the substance between minutes 13 and 18 converted the substance from a _______________ to a _______________ state. This heat energy is called the latent heat of vaporization. (An interesting fact.) Beyond point E, the substance is still in the ___________________ phase, but the molecules are moving _____________________ as indicated by the increasing temperature. Substance Bolognium Unobtainium Foosium Melting point 20 °C 40 °C 70 °C Boiling point 100 °C 140 °C 140 °C Which of these three substances was likely used in this phase change experiment? _____________________________ Calorimetry / Phase Change Problems All work must be done on a separate piece of paper for credit. Solve the following problems. As always, include work and show the units to ensure full credit. Water’s specific heat (s) = 0.5 cal/g oC | Water’s specific heat (l) = 1 cal/g oC | Water’s specific heat (g) = 0.45 cal/g oC heat of fusion (Hf) = 80 c/g | heat of vaporization (Hv) = 539 cal/g 1. A 445 g sample of ice at –58oC is heated until its temperature reaches –29oC. Find the change in heat content of the system. 2. A 152 g sample of ice at –37oC is heated until it turns into liquid water at 0oC. Find the change in heat content of the system. 3. A 218 g sample of steam at 121oC is cooled to ice at –14oC. Find the change in heat content of the system. 4. If 161 g of water at 85oC is cooled to ice at 0oC, find the change in heat content of the system. 5. A 79 g sample of water at 21oC is heated until it becomes steam with a temperature of 143oC. Find the change in heat content of the system. 6. If a 348 g sample of steam at 127oC is cooled to 103oC, find the change in heat content of the system. 7. In going from ice at –34oC to steam at 138oC, a sample of water absorbs 1.41 x 105 J. Find the mass of the sample. Find the energy change of the system required to change… 8. …150 g of ice at –15oC to ice at –63oC. 9. …200 g of water at 4oC to water at 88oC. 10. …54 g of steam at 150oC to steam at 112oC. 11. …18 g of water at 0oC to ice at 0oC. 12. …215 g of water at 100oC to steam at 100oC. 13. …44 g of ice at –13oC to water at 58oC. 14. …330 g of steam at 100oC to ice at 0oC. 15. …1200 g of steam at 118oC to water at 100oC. 16. …60 g of water at 43oC to steam at 140oC. 17. …400 g of ice at –38oC to steam at 160oC. 18. If 20 g of silver at 350oC are mixed with 200 g of water at 30oC, find the final temperature of the system. 19. If 26 g of water at 18oC are mixed with 49 g of water at 70oC, find the final temperature of the system. 20. If 84 g of water at 22oC are mixed with 150 g of ethanol at 88oC, find the final temperature of the system. 21. If 24 g of sodium chloride at 25oC are mixed with 272 g of mercury at 50oC, find the final temperature. 22. 240 g of water (initially at 20oC) are mixed with an unknown mass of iron (initially at 500oC). When thermal equilibrium is reached, the system has a temperature of 42oC. Find the mass of the iron. 23. 135 g of aluminum (initially at 400oC) are mixed with an unknown mass of water (initially at 25oC). When thermal equilibrium is reached, the system has a temperature of 80oC. Find the mass of the water. 24. In the lab, an experimenter mixes 75.0 g of water (initially at 30oC) with 83.8 g of a solid metal (initially at 600oC). At thermal equilibrium, he measures a final temperature of 50.0oC. What metal did the experimenter probably use? 25. A 97 g sample of gold at 785oC is dropped into 323 g of water, which has an initial temperature of 15oC. If gold has a specific heat of 0.129 J/g.oC, what is the final temperature of the mixture? Assume that the gold experiences no change in its state of matter. 26. If 59 g of water at 13oC are mixed with 87 g of water at 72oC, find the final temperature of the system. 27. A 38 g sample of ice at –11oC is placed into 214 g of water at 56oC. Find the system’s final temperature. 28. 25 g of 116oC steam are bubbled into 0.2384 kg of water at 8oC. Find the final temperature of the system. 29. A 322 g sample of lead (specific heat = 0.138 J/goC) is placed into 264 g of water at 25oC. If the system’s final temperature is 46oC, what was the initial temperature of the lead? 30. A sample of ice at –12oC is placed into 68 g of water at 85oC. If the final temperature of the system is 24oC, what was the mass of the ice?