Answer Happy

Questions # 11-15: Shown here is the PT phase diagram for an unknown substance. 4.0 First, identify the substance's state-of- matter in each of the three large regions of the diagram. Then answer the following questions: 3.0 11. (0.5 pt.) At 75 K, this substance is solid at all pressures. 2.0 A. True B. False 1.0 12. (0.5 pt.) At the pressure and temperature in your room right now, this substance would be in which state? A. solid 100 400 B. liquid C. gas 13. (1 pt.) At 2.0 atm pressure, the substance's boiling point is approximately: 14. (1 pt.) This substance cannot exist as a liquid if it is at a pressure below what value? atm 15. (0.5 pt.) If kept at a constant pressure of 1.5 atm while heated from 50 K to 300 K, what happens to the substance? A. It only melts. B. It only boils. C. It only sublimates. D. It first melts, then later boils.. pressure [atm] 200 300 temperature [K]
Questions #16-17: At a science museum, a stationary bicycle is connected to an electric generator. By pedaling steadily, a museum visitor is able to keep a 75-watt light bulb fully lit for 45 seconds. 16. (1 pt.) What is the total energy, in kilojoules, consumed by the light bulb during this time? 17. (1 pt.) Suppose that only (10.-20.3% of the person's food-energy is actually delivered to to the light bulb as electrical energy, while the remainder is expended on biological processes, friction, and other inefficiencies in the bicycle and generator. (Laulima will contain a randomized value within the range shown) How many dietary Calories of food-energy did the person use during the time described above? Questions #18-19: A particular kitchen blender delivers 1100 watts of mechanical power while blending the mixed fruit in its carafe to make a smoothie. Assume that 100% of this power is absorbed by the food as the blades spin. 18. (1 pt.) If the blender runs for 23 seconds, what is the total energy, in kilojoules, delivered to the food? 19. (1.5 pts.) If the food has a total mass of (1.0-2.0) kg and an average specific heat capacity of (3.0-4.0) kJ/(kg-K), what is the average temperature increase of the food, in degrees Celsius? (Laulima will contain randomized values within the ranges shown.) Assume rapid heat transfer and mixing within the food, and that 100% of the heat remains in the food. Assume no phase transitions for the food. 20. (2 pts.) A 2.20-kg iron pot contains 3.00 kg of water, all initially at 25.0°C. A hot iron horseshoe with a mass of (300.-600.) grams is dropped into the water. After the pot, horseshoe, and water all reach thermal equilibrium, the final temperature of all three is 33.0°C. What was the initial temperature of the hot horseshoe, in degrees Celsius? (Laulima will contain a randomized value within the range shown) Assume rapid heat transfer within the system, and that the system is fully insulated from its surroundings. Specific heat capacities: 450.J/(kg-K) Cat4186 J/(kg-K) 21. (2 pts.) How much total heat is required to transform (1.00-2.00) liters of liquid water that is initially at 25.0°C entirely into H₂O vapor at 100. C? Convert your final answer to megajoules. (Laulima will contain a randomized value within the range shown.) Assume rapid heat transfer within the system, and that the system is fully insulated from its surroundings. Physical values for H:0, although you may not need to use all of them: Cliquid water 4186 J/(kg-K) Le-334,000 J/kg L.-2,256,000 J/kg 22. (2 pts.) How much total heat is needed to fully melt (10.0-20.03 kg of silver, if the silver starts as a 25.0°C solid? Convert your final answer to megajoules. (Laulima will contain a randomized value within the range shown.) Assume rapid heat transfer within the system, and that the system is fully insulated from its surroundings Physical values for silver. T=961C Cold Ag -230. J/kg-K L-88.0 kJ/kg 23. (1 pt.) A particular sidewalk in a northern city is made up of a series of 1.5-meter-long stone slabs, whose coefficient of thermal expansion is 2.1 x 10 K. If the city's coldest winter temperatures are typically -22°C, and its warmest summer temperatures are typically 34°C, how much does each slab's length change as it undergoes these extremes? Convert your final answer to millimeters.