1. Chemistry. Please help!

    For the problems below, I have the answers written but from questions d-i, I don't understand how they got the answer. I tried doing it and somehow I messed up with the formula with 3/2 and 5/2 so please show work on how they got the answers for d-i. In
  2. thermodyn. please check work

    What is the sign of heat(Q), Work(W), or Temperature for these following situations. Say if it's +,-, or 0. 1)You hit a nail with a hammer: +W, Q=0, T=0 2)You hold a nail over a Bunsen burner: Q=+Q, Temp:constant, W=0 3)You compress the air in a bicycle
  3. Chemistry

    2 Al(s) + 3 Cl2(g) → 2 AlCl3(s) Into a cylinder with a moveable piston (pressure stays constant), a piece of aluminum is placed and chlorine gas is added. After they react, the temperature inside the piston is considerable higher than its initial
  4. physics

    Consider 3 liters of an ideal (monatomic) gas at a pressure of 34 atm and a temperature of 356K. Call this state of the system A. Using the ideal gas law, calculate the number of moles of gas present in the system. 3.49 The temperature of the system is
  5. Chemistry

    You carry out an exothermic reaction inside a Styrofoam cup calorimeter, using a temperature probe to monitor the temperature throughout the reaction. You find that the temperature increases 7.40 °C during the reaction. The specific heat of the reaction
  6. Chemistry

    Calculate the chage in enthalpy produced by dissolving 14.3 g NaOH in 65.0 g of water if the temperature increases 49.1 C and the specific heat of water is 4.18 J/g C. So this is just q=mcΔt Do you add 14.3 and 65.0 to use for m? Also would the sign for
  7. Physics

    A commercial heat pump has CP=3 when the indoor temperature is 20°C and the outdoor temperature is 6°C. How much work is required to operate it if 3*10^6J of heat must be transferred to the room each hour?
  8. PHYSICS

    Identify the following gas compression descriptions as adiabatic, isothermal or isobaric. a. As the gas compresses, the internal energy ÄU, decreases when the temperature decreases; the work done on the gas is greater than the heat removed from the gas:
  9. Physics

    The temperature of a monatomic ideal gas remains constant during a process in which 4500 J of heat flows out of the gas. How much work (including the proper + or - sign) is done on the gas? J
  10. science

    A heat engine draws 800J of heat from its high temperature source and discards 450J of exhaust heat into its cold temperature reservoir during each cycle.How much work does this engine perform per cycle?
  11. Chemistry - check answers

    Can someone please check my answers and make sure they're correct? A) How much heat would it take to raise the temperature of 46.0 g of water from 90.0 to 100.0 C? Answer using correct sig figs, sign, and units. My answer: +1.92x10^3 J B) How many joules
  12. physic

    A Carnot engine takes an amount of heat QH = 113 J from a high-temperature reservoir at temperature TH = 1170°C, and exhausts the remaining heat into a low-temperature reservoir at TL = 13.3°C. Find the amount of work that is obtained from this process
  13. Physics

    During a particular thunderstorm, the elctric potential difference between the clouds and the groud is Vcloud-Vgroud = 10^9 volts with the cloud being at the higher potential. Now, there is a lightning flash in which a charge of -25C is transferred from
  14. PHYSÝCS

    Suppose a person metabolizes 2150 kcal/day. a) With a core body temperature of 37.1°C and an ambient temperature of 21.3°C, what is the maximum (Carnot) efficiency with which the person can perform work? b) If the person could work with that efficiency,
  15. physics

    Suppose a person metabolizes 2250 kcal/day. a) With a core body temperature of 36.9°C and an ambient temperature of 21.5°C, what is the maximum (Carnot) efficiency with which the person can perform work? b) If the person could work with that efficiency,
  16. PHYSICS

    Three moles of an ideal gas are compressed from 5.5*10^-2 to 2.5*10^-2 m^3. During the compression, 6.1*10^3J of work is done on the gas, and heat is removed to keep the temperature of the gas constant at all times. Find the temperature of the gas. I
  17. Biology

    In what situations would sampling work best for estimating population size, in what situations would mark and recapture work best and why?
  18. Thermodynamic.

    You evaluate a number of different temperature measuring devices in your laboratory classes. a. Explain how at least three operated and justify why you would choose those devises for the scenario below. ‘A local company requires measuring devices to
  19. chemistry

    Use the following values for the arrows in the drawing: a = 185 J of heat; b = 45 J of heat; c = 115 J of work; d = 40 J of work; e = 65 J of work; and f = 190 J of heat. Find the change in the internal energy of object A only. Use the First Law of
  20. physics

    lead is a soft, dense metal with a specific heat of 0.028 kcal/kg degrees C, a melting point of 328.0 degrees C and a heat of fusion of 5.5 kcal/kg. How much heat must be provided to melt a 250.0 kg sample of lead with a temperature of 20.0 degrees
  21. thermodynamics

    3.4 A heat engine operates between two heat reservoirs with temperatures of 560 and 280 K a) The heat engine itself has a temperature of 560 K during heat addition from the 560 K reservoir and a temperature of 280 K during heat rejection to the 280 K
  22. Urgent-Chemistry Help

    I need help with the heat effects and calorimetry worksheet. Please explain how to solve it! Thank you so much! A metal sample weighing 45.2g and at a temperature of 100.0 C was placed in 38.6g of water in a calorimeter at 25.6 C. At equilibrium the
  23. Chemistry

    when pure sodium hydroxide is dissolved in water , heat is evolved in a laboratory experiment measure a molar heat of solution of sodium hydroxide the following procedure was followed. to a calorimeter containing 300g of water at 20.0 C and 10.65g of NaOH
  24. thermodynamics

    If a carnot engine receives heat from a heat source and discharge 1000J to a heat sink at temperature of 27C in each cycle, calculate the heat received and the work performed by the engine in each cycle
  25. PHYSICS

    A copper vat is 10 m long at room temperature (20 degrees C). How much longer it is when it contains boiling water at 1 atm pressure? Air in a balloon does 50 J of work while absorbing 70 J of heat. What is its change in internal energy? A bottle
  26. physics

    The hot reservoir for a Carnot engine has a temperature of 926 K, while the cold reservoir has a temperature of 441 K. The heat input for this engine is 3730 J. The 441-K reservoir also serves as the hot reservoir for a second Carnot engine. This second
  27. physics- please check

    a. Two sticks are rubbed together to start a fire. b. A firecracker explodes. c. A red-hot iron bar is set aside to cool. In which of the situations listed above is energy being transferred as heat to the system in order for the system to do work? I would
  28. Chemistry

    I am stuck on b)... Reacting 1 L of H2(g) with 1 L C2H2(g) (both at STP) results in the formation of 1 L of C2H4(g) if the reaction is maintained at the same conditions (STP) and goes to completion. If this reaction produced 6.3 kJ of heat (absorbed by the
  29. physics

    (a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by
  30. physics

    (a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by
  31. physics

    (a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by
  32. physics

    (a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by
  33. Chemistry

    4. A typical car engine produces 44,000 kJ of heat in an hour. The cooling system has a capacity of 8.40 L and is filled with a 50:50 mixture of anti-freeze (specific heat capacity of 8.37 J/g-oC, density of 1.038 g/mL). In maintaining a constant engine
  34. Physics

    A 0.1134kg spherical meteor of diameter 3 cm enters the earth’s atmosphere at an elevation of 121920m with a velocity of 13411.2 m/s. The meteor’s temperature is -73.15˚C. The specific heat at constant volume (Cv) of the meteor is 800 J/kg˚C. (a) If
  35. chemistry

    The heat lost or gained by a system is related to its temperature change by a property called its heat capacity. The molar heat capacity of metals at or above room temperature equals 24.92 J/K.mol. The temperature of a block of lead (MM 207.2) was raised
  36. physic

    If the energy used to heat up a block of 2kg of copper is 115.8 kJ, what is the temperature it was heated to if the starting temperature was 100oC and the specific heat capacity is 386 J/kgK. temperature needed = energy/ mass x specific heat capacity
  37. Physics

    Q: Japanese honeybees have a unique defensive mechanism against their natural predator, the giant hornet. When threatened by a hornet attacking the nest, worker bees will work together to surround the hornet, and then vibrate to create heat. If enough bees
  38. Chemistry

    Calculate the amount of heat energy transferred in the following situations: the temperature of 1.0g water rises from 22.5 degrees C to 24.5 degrees C. Feel like I am missing givens. Help! There are a few more like this but I just need to know how to set
  39. Physics

    If the air temperature is the same as the temperature of your skin (about 30 degrees Celcius), your body cannot get rid of heat by transferring it to the air. In that case, it gets rid of the heat by evaporating water (sweat). During bicycling, a typical
  40. Science

    1. How much heat energy is lost by 3 kg of water when it cools from 80 degrees C to 10 degrees C? 2. A 300 g piece of aluminum is heated from 30 degrees C to 150 degrees C. What amount of heat energy is absorbed? 3. Determine the temperature change in each
  41. Chemistry

    If 15.0 mL of a 1.5M HCl solution at 22.5 degrees C is mixed with 25.0mL of a 1.5M NaOH solution at 21.5 degrees C that is in a calorimeter, and the final mixed solution temperature ends up at 28.5 degrees C, 1.)what is the balanced equation for this
  42. chemistry

    A 0.016076-mol sample of an organic compound was burned in oxygen in a bomb calorimeter. The temperature of the calorimeter increased from 23.7oC to 24.5oC. If the heat capacity of the calorimeter is 4.98 kJ (oC)-1, then what is the constant volume heat of
  43. chemistry

    A 0.016076-mol sample of an organic compound was burned in oxygen in a bomb calorimeter. The temperature of the calorimeter increased from 23.7oC to 24.5oC. If the heat capacity of the calorimeter is 4.98 kJ (oC)-1, then what is the constant volume heat of
  44. chemistry

    If all the energy obtained from burning 1.23 pounds of propane (fuel value is 11.09 kcal/g) is used to heat 125.0 kg of water at an initial temperature of 21.8 °C, what is the final temperature? Hint: The heat, q, released by burning propane is absorbed
  45. science grade 5

    how is heat related to temperature? Temperature tells us the DEGREE of heat; i.e., how hot is something. A temperature of 98.6 F is normal body temperature. A hot day is when the temperature is 95 degrees F. A cold day is when it is freezing outside. But
  46. Chemistry

    Check my work & answer please. I need to make sure I am able to do this type of problem correctly. A typical car engine produces 44,000 kJ of heat in an hour. The cooling system has a capacity of 8.40 L and is filled with a 50:50 mixture of anti-freeze
  47. Chem

    When 3.00 g of butane, C4H10, are combusted in a calorimeter containing 800. g of water, the temperature of the water changes by 44.4 °C. What is the heat of combustion of butane in kilojoules per mole? The molar mass of butane is 58.123 g/mol. The
  48. physics

    Temperature is distinguished from heat when we note that whereas temperature is ____________________. A) None of these.B) measured in degrees, heat is measured in units of energy.C) a measure of average translational kinetic energy per molecule, heat is
  49. principles of physics

    Temperature is distinguished from heat when we note that whereas temperature is ____________________. A) None of these.B) measured in degrees, heat is measured in units of energy.C) a measure of average translational kinetic energy per molecule, heat is
  50. physics

    1. Temperature is distinguished from heat when we note that whereas temperature is ____________________. A) None of these.B) measured in degrees, heat is measured in units of energy.C) a measure of average translational kinetic energy per molecule, heat is
  51. chemistry

    To make a pocket warmer from sodium acetate and vinyl, how do you estimate how many grams to use? to work out the 'q' is it the heat capacity of the water it is dissolved in that you use? What temperature do you want it to get to and how do you factor in
  52. Physics

    For the situation: "A moving crate slides to a halt on a rough surface" Does temperature increase, decrease, or not change? Are work and heat positive, negative, or zero? Does thermal energy increase, decrease, or not change? My answer key says temperature
  53. math

    Here's my question: Determine if each system has one, two, or no solutions. (Show your work - 3 marks each) a)y=2x^2-2x+1 and y=3x-5 b)y=x^2+3x-16 and y=-x^2-8x-18 Here's my work on the question: a) x=(-b plus/minus sign (square root b^2-4ac)/(2a) x=(--2
  54. chemistry

    3. If 15.0 mL of a 1.5M HCl solution at 21.50C is mixed with 25.0mL of a 1.5M NaOH solution at 21.50C that is in a calorimeter, and the final mixed solution temperature rises to 28.50C, what is the ΔHrxn for this process? Assume that Ccalorimeter =
  55. Physics

    In which of the situations listed below is energy being transferred as heat to the system in order for the system to do work? In which situation is work being done on the system in order for energy to be transferred from the system as heat? a. Two sticks
  56. Physics conceptual

    You hold an inflated balloon over a hot air vent in your house and watch it slowly expand. You then remove it and let it cool back to room temperature. During the expansion, which was larger: the heat added to the balloon or the work done by the air
  57. Physics

    You hold an inflated balloon over a hot air vent in your house and watch it slowly expand. You then remove it and let it cool back to room temperature. During the expansion, which was larger: the heat added to the balloon or the work done by the air
  58. Chemistry

    The specific heat of solid copper is 0.385 J/g*C. What thermal energy change occurs when the temperature of a 40.10g sample of copper is cooled from 42.9C to 10.0C? Be sure to give you answer the proper sign. I know this is part of the answer which
  59. Chemistry

    The specific heat of solid copper is 0.385 J/g*C. What thermal energy change occurs when the temperature of a 40.10g sample of copper is cooled from 42.9C to 10.0C? Be sure to give you answer the proper sign. I know this is part of the answer which
  60. Physics please check

    Three moles of an ideal monatomic gas are at a temperature of 345 K. Then, 2531 J of heat are added to the gas, and 1101 J of work are done on it. What is the final temperature of the gas? delta U= 3/2nR(T final -T initial) (2531J - 1101J) =
  61. physics.......please help!!!

    In which of the situations listed below is energy being transferred as heat to the system in order for the system to do work? In which situation is work being done on the system in order for energy to be transferred from the system as heat? a. Two sticks
  62. Science

    Organisms that maintain a constant body temperature rely on the heat produced by cells. Where does this heat come from? A) Special metabolic pathways exist just for the production of heat. B) Mitochondria produce heat in the form of ATP. C) Plants store up
  63. chemistry

    A piece of chocolate cake is burned with oxygen in a bomb calorimeter. The temperature of 3368 grams of H2O in the calorimeter is raised by 0.52 K. What is ∆E, including the sign, for the combustion of this piece ot chocolate cake? Assume no heat is
  64. engineering

    To make a pocket warmer from sodium acetate and vinyl, how do you estimate how many grams to use? to work out the 'q' is it the heat capacity of the water it is dissolved in that you use? What temperature do you want it to get to and how do you factor in
  65. Science

    A man relaxes in his hot tub after a long day at work. hid ody temperature is 98.6 F. The temperature of the water in the hot tub is 102 F. How does heat transfer A) Heat does not transfer between his body and the water. B) Heat transfers to his body from
  66. College Chemistry

    For each trial, enter the amount of heat lost by the calorimeter, qcalorimeter. Be careful of the algebraic sign here and remember that the change in temperature is equal to the final temperature minus the initial temperature. Report your answer using 4
  67. Physics

    If the air temperature is the same as the temperature of your skin (about 30.0 oC), your body cannot get rid of heat by transferring it to the air. In that case, it gets rid of the heat by evaporating water (sweat). During bicycling, a typical 70.0kg
  68. chm

    You are heating crushed ice and a small amount of water and monitoring the temperature of the icy slurry until it reaches the point were the ice is nearly melted. How does the temperature change during this process? The temperature drops as the ice absorbs
  69. chemistry(check my explanation)

    sorry to repost this question but i'm confused on this part The solubility of borax is directly proportional to temperature. Therefore, the sign of H is A. negative B. positive C. unknown with the given information like you said earlier, borax dissolves
  70. Chemistry

    I have this problem: How much heat energy is required to raise the temperature of 0.365kg of copper from 23.0 ∘C to 60.0 ∘C? The specific heat of copper is 0.0920 cal/(g⋅∘C). I did the equation using formula Heat= mass x change in temperature x
  71. science

    The specific heat capacity of the lava is 1600 J kg^-1 degres celsuis ^-1. when all the erupted lava cools from the eruption temperature of 1050 degrees Celsius to 15 degrees celsius, the heat released is 2 x 10 ^15 J. calculate a value for the total mass
  72. please help me, physics

    Five moles of a monatomic ideal gas expand adiabatically, and its temperature decreases from 410 to 200 K. (a) What is the work done by (or done to) the gas? Include the algebraic sign. J (b) What is the change in the internal energy of the gas? Include
  73. Physics

    Three moles of a monatomic ideal gas expand adiabatically, and its temperature decreases from 430 to 160 K. (a) What is the work done by (or done to) the gas? Include the algebraic sign. J (b) What is the change in the internal energy of the gas? Include
  74. Physics

    Three moles of a monatomic ideal gas expand adiabatically, and its temperature decreases from 430 to 160 K. (a) What is the work done by (or done to) the gas? Include the algebraic sign. J (b) What is the change in the internal energy of the gas? Include
  75. Physics

    The graph shows the temperature versus time relationship for 2 kg of particular substance. The substance is in the solid state at a room temperature of 20 degrees Celsius. - The 100 joules of heat is needed to completely change the substance from a solid
  76. math,

    A jeweler is heating a gold bar. It takes 7 joules of heat to raise the temperature of the bar 1°C. The initial temperature of the bar is 25°C. Use this information for Items 4–11. 4. Make a table that shows how many joules of heat would be required to
  77. math

    A jeweler is heating a gold bar. It takes 7 joules of heat to raise the temperature of the bar 1°C. The initial temperature of the bar is 25°C. Use this information for Items 4–11. 4. Make a table that shows how many joules of heat would be required to
  78. algebra

    A jeweler is heating a gold bar. It takes 7 joules of heat to raise the temperature of the bar 1°C. The initial temperature of the bar is 25°C. Use this information for Items 4–11. 4. Make a table that shows how many joules of heat would be required to
  79. Physics

    In a house the temperature at the surface of a window is 22.3 °C. The temperature outside at the window surface is 2.82 °C. Heat is lost through the window via conduction, and the heat lost per second has a certain value. The temperature outside begins
  80. physics

    In a house the temperature at the surface of a window is 20.1 °C. The temperature outside at the window surface is 2.72 °C. Heat is lost through the window via conduction, and the heat lost per second has a certain value. The temperature outside begins
  81. Math

    I'm trying to help my nephew with some homework and am hopeless. Please help with these questions: If 180 calories of heat were added to 50 grams of copper, what would the change in temperature be? (specific heat of copper = .09) What would the temperature
  82. chem

    Which statement is wrong? 1. Adding the same amount of heat to two different objects will produce the same increase in temperature. 2. When the same amount of heat produces different changes in temperature in two substances of the same mass, we say that
  83. Chemistry

    106 g of iron at 84.0°C are placed in contact with 205 g of silver at 11.0°C. If no heat is lost to the surroundings, what is the final temperature of the metals? The specific heat of iron is 0.418 J/g·°C and that of silver is 0.251 J/g·°C. 92.0 g of
  84. CHEM

    You have a bottle of water. The water has a mass of 29 grams. You heat the water with 102 calories of heat and the final temperature of the water is 43°C. What was the initial temperature (in Celsius) of the water before you added the heat? The specific
  85. Science

    90 calories of heat is added to 1 gram of fresh water with an initial temperature of 10 degrees Celcius. What is the final temperature of this liquid? (latent heat of fusion = 80cal/g°C, latent heat of vaporization = 540 cal/g°C)
  86. Chemistry (11th)

    When A + B --> C then this reaction occurs in water, heat is given off. 1) Will the temperature of water go up or go down ? - is the asnwer down ? since the energy is released to the surrounding. 2) What is the sign for delta H ? + or - ?
  87. chemistry

    If heat of reaction, Ca(s) + 2H+(aq) Ca2+(aq) + H2(g) , is - 544 kJ/mol, heat of reaction, CaO(s) + 2H+(aq) Ca2+(aq) + H2O(l) , is -192 kJ/mol. and heat of formation of water is -286, what is heat of CaO? Ca(s) etc is equation 1. CaO + 2H^+ etc is equation
  88. Chemistry

    Why would you subtract the heat of a calorimeter when calculating heat of the reaction? hint: the heat of the calorimeter is the amount of heat that the calorimeter absorbs from the solution-each calorimeter will absorb a certain amount of heat, which
  89. physics

    When 1180 J of heat are added to one mole of an ideal monatomic gas, its temperature increases from 272 to 292 K. Find the work done by the gas during this process. I know the specific heat is Q/delta T, so C = (1180 J)/(20K) = 59. This seems like any easy
  90. chemistry

    1) Calculate the specific heat capacity (J/g oC) of iron, if a 803 g sample lost 937.4 J of heat energy in going from an initial temperature of 5.50 oC to a final temperature of 2.90 oC. 2)Calculate the final temperature (oC) of a 243 g sample of water
  91. help me please physics

    A monatomic ideal gas expands from point A to point B along the path shown in the drawing. (a) Determine the work done by the gas. J (b) The temperature of the gas at point A is 198 K. What is its temperature at point B? K (c) How much heat has been added
  92. thermodynamics

    A heat engine, X, operates between a reservoir at 1000˚C and a body at 600˚C. Heat transfer to the heat engine is 1000 kJ and work output is 220 kJ. Another Engine, Y, operates between, the body at 600˚C and the atmosphere at 27˚C. Heat rejected to the
  93. Physics

    Just as no mechanical device can be 100% efficient, no heat engine can transfer 100% of its heat to a single object. Some of the heat energy must be wasted (released into the environment). We have a heat engine that produces 150 J of heat, does 40 J of
  94. Chemistry

    1) Determine the amount of heat in kJ given off when 1.26 x 10^4 g of NO2 are produced according to the equation: 2NO (g) + O2 (g) --> 2NO2 (g) and delta (H) = 483.6 kJ/mol 2) A sheet of gold weighing 10 g and at a temperature of 18 degrees C is placed on
  95. Chemistry

    Calculate the heat capacity of a sample of radiator coolant if a temperature rise from 5 to 107℃ requires 932 J of heat. My work: c=q/mΔT c=932J/(?)(107℃-5℃)
  96. physics

    A theoretical gasoline engine runs with 76 percent efficiency. It is calculated that it expels 3.25*10^4 J of heat. a. Find the heat absorbed in one cycle. b. Find the work output in one cycle. All this comes from the definition of efficiency.
  97. chemistry

    Some physical properties of water are shown below: melting point 0.0°C boiling point 100.0°C specific heat solid 2.05 J/g·°C specfic heat liquid 4.184 J/g·°C specific heat gas 2.02 J/g·°C ΔH° fusion 6.02 kJ/mol ΔH° vaporization 40.7 kJ/mol 80.0
  98. Science

    For my science class I have to make a machine that attempts to convert heat energy into work. I'm not really sure how to do this, but I do have some ideas, however I'm not all the way there. If you told me your opinion of my ideas or if you gave me one of
  99. Math

    A heat exchanger is used to warm apple cider using steam as the heat source. The cider is heated from an initial temperature of 4°C to a final temperature of 65°C. The steam enters the heat exchanger as 50% quality steam and exits as water condensate at
  100. Food Chemistry

    A heat exchanger is used to warm apple cider using steam as the heat source. The cider is heated from an initial temperature of 4°C to a final temperature of 65°C. The steam enters the heat exchanger as 50% quality steam and exits as water condensate at