Writing Assignment 1_2(1)(1)

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Chemistry

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Feb 20, 2024

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Writing Assignment 1-2 Answer the following questions. Do not send in a partially completed assignment. Answer each question as completely as possible. Do not just submit the final answer. Show the main steps in the solution. Use Equation Editor or MathType for typing symbols and equations when needed. Submit your assignment in MS Word docx, doc, or rich format. Submissions in other formats will not be graded and will be treated as non-submissions. 1. A rubber balloon is blown up and the end tied. Is the pressure inside the balloon greater than, less than, or equal to the ambient atmospheric pressure? Explain. The pressure inside the balloon is greater than the ambient atmospheric pressure. Since it is closed space. 2. Death Valley holds the record for the highest temperature in the United States. On July 10,1913, at a place called Furnace Creek Ranch, the temperature rose to 134 0 F. The lowest temperature occurred at Prospect Creek Park in Alaska on January 23, 1971, plummeted to -79.8 0 F. (a) Convert these temperatures to Celsius scale. (b) Convert Celsius temperatures to Kelvin. the formula: K= C+273.15 C=( F−32)×5/9 A . 56.67 C., −62.11 C . B. 329.82K., 211.04K. 3. An underground tank can hold 1.00×10 3 gallons of gasoline at 52 0 F. If the tank is being filled on a day when outdoor temperature (and gasoline in a tanker truck) is 95 0 F, how many gallons from the truck can be poured into the tank? Assume the temperature of gasoline quickly cools from 95 0 F to 52 0 F upon entering the tank. ΔTc=5/9(ΔTF)=5/9(95−52)=23.9 C V95F=V52F(1+ΔT) =1.00×103(1+(9.6×10−4)(23.9))=1.02×10^3gal 4. During inhalation, a person’s diaphragm, and intercostal muscles contract, expanding the chest cavity and lowering internal pressure below ambient so the air flows in through the mouth and nose to the lungs. Suppose a person’s lung holds 1250 mL of air at a pressure of 1.00 atm. If the person expands the chest cavity by 525 mL while keep the nose and mouth closed, what will be the pressure in the lungs in atm? Assume the air pressure remains constant in the process. P1 V1=P2 V2 P2=1.00atm 1250mL / 1775mL P2=0.705atm
5. A 7.00 L vessel contains 3.50 moles of ideal gas at a pressure of 1.60 x 10 6 Pa. Find (a) the temperature of the gas and (b) the average kinetic energy of a gas molecule in the vessel. (c) What additional information would you need if you were asked to find the average speed of a gas molecule? a) A. = (1.60×106) (7.00)/(3.50)(8.31)=666 K B. KEavg=2/3(1.38×10^−23)(666)=1.66×10−20J C. we would need the molecular mass 6. When a driver brakes an automobile, the friction between the brake drum and the brake shoes converts the car’s kinetic energy into thermal energy. If a 1500 kg automobile travelling at 30 m/s comes to a halt, how much does the temperature rise in each of the four 8.00 kg iron brake drum? (The specific heat of iron drum is 448 J/kg. 0 C) KE initial=1/2×1500×(30)^2 Q=KEinitial=675,000J ΔT=675,000/(4×8.00×448) = 47.09 degC 7. A 60 kg runner expends 3.00 x 10 2 W of power while running a marathon. Assuming 10.0% of the energy is delivered to the muscle tissue and that the excess energy is removed from the body primarily by sweating, determine the volume of bodily fluid (assume it is water) lost per hour. (At 37.0 °C, the latent heat of vaporization of water is 2.41 x 10 6 J/kg). m=9.72×10^5/2.41×10^6 Volume=0.404/1000 4.04×10^−4m^3 8. A Styrofoam box has a surface area of 0.80 m 2 and a wall thickness of 2.0 cm. The temperature of the inner surface is 5.0 °C, and the outside temperature is 25 °C. If it takes 8.0 h for 5.0 kg of ice to melt in the container, determine the thermal conductivity of the Styrofoam. Q=kAΔT/d k=3.34×10^4/(0.80) 20
K=2093.75W/(m ⋅∘ C) 9. A power plant has been proposed that would make use of the temperature gradient in the ocean. The system is to operate between 20.0 °C (surface water temperature) and 5.00 °C (water temperature at a depth of about 1 km). (a) What is the maximum efficiency of such a system? (b) If the useful power output of the plant is 75.0 MW, how much energy is absorbed per hour? (c) In view of your answer to part (a), do you think such a system is worthwhile (considering that there is no charge for fuel)? A.η=1−293.15/278.15 = 5.4% B.Qabsorbed=0.054×75.0×10^6×3600 Qabsorbed=1.89×10^12 J C. Since it has a low efficiency of the new system it would not be worthwhile. 10. A weightlifter has a basal metabolic rate of 80.0 W. As he is working out, his metabolic rate increases by 650.0 W. (a) How many hours does it take him to work off a 450.0 Calories bagel if stays in bed? (b) How long does it take him if he is working out? Calculate the amount of mechanical energy to lift a 120.0 kg barbell 2.00 m high? (d) He then drops the barbell and lifts it repeatedly. How many times per minute must he repeat the process to do the amount of mechanical work equivalent to his metabolic rate increase of 650.0 W during the exercise? (e) Could he do repetitions at the rate found in part(d) at the given metabolic level? Explain. A. Time = 450 x 4.186/80 = 6.6540625 x 10^-3 hours B. Time = 450 x 4.186/730 = 7.1678x 10^-4 hrs c. 120 x 2 x 9.8 = 2352 J D.650/2352 * 60 = 16.58 = 17 times a minute E. No since 80 W is less than required
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