Popular questions and responses by marcus
  1. chemistry

    When 50.0mL of 1.20 M of HCl (aq)is combined with 50.0mL of 1.30 M of NaOH (aq) in a coffee-cup calorimeter, the temperature of the solution increases by 8.01 Degrees C. What is the change in enthalpy for this balanced reaction? HCl(aq) + NaOH(aq)

    asked on November 14, 2012
  2. Chemistry

    Which of the following solutes in aqueous solution would be expected to exhibit the smallest freezing-point lowering (assuming ideal behavior? 0.1 m NaCl .2 m CH3COOH .05 m Al2(SO4)3 .1 m MgCl2 .25 m NH3 What would be the steps to picking the right option?

    asked on February 19, 2013
  3. Chemistry

    The molal boiling-point constant for water is 0.51 degrees C/molal. The boiling point of a 1.00 molal solution of Ca(NO3)2 should be increased by: A.) exactly 1.53 or B.) Somewhat less than 1.53 This is how I worked the problem: Ca(NO3)2 dislocates into 3

    asked on February 21, 2013
  4. chemistry

    At constant pressure and 25 degrees C, what is delta H for the reaction 2C2H6(g) + 7O2(g) --yields-- 4CO2(g) + H2O(l) if the complete consumption of 11.3 g of C2H6 releases -586.3 kJ of heat energy? (11.3=.38 mol C2H6)

    asked on November 14, 2012
  5. Chemistry

    Which of the following pure liquids is the best solvent for sodium fluoride? CCl4 C2C6 HCl BCl3 or PCl5 My guess would be either CCl4 or C2C6, I need to know the reasoning behind the correct answer.

    asked on February 19, 2013
  6. Trigonometry

    While cruising at a steady speed of 400 km/h, you identify a storm cloud straight ahead 45 km away. To avoid turbulence, you start climbing at an angle of elevation of 15°. If you maintain this speed and direction for 6 min, how far will you be from the

    asked on June 13, 2019
  7. Chemistry

    A solution contains 10.0 g pentane, C5H12, 10.0 g hexane, C6H14 and 10.0 g benzene, C6H6. What is the mole fraction of hexane? I figured the equation would be: ___ M Hexane x 10 Divided by 30 =Mole fraction of Hexane?

    asked on February 10, 2013
  8. pre algebra with pizzazz 239

    why didn't the circus managers want their human cannonball to quit?

    asked on October 27, 2011
  9. Chemistry

    What is the vapor pressure of a aqueous solution containing 10 % (by weight) ethylene glycol (62 g/mol) at 25 °C. PH2O = 24.3 torr at 25°C?

    asked on February 10, 2013
  10. chemistry

    A 94.7 g sample of silver (s= 0.237 J/(g x Degree C)), initially at 348.25 Degrees C , is added to an insulated vessel containing 143.6 g of water (s=4.18 J/(g x Degree C)), initially at 13.97 Degrees C. At equilibrium, the finial temperature of the

    asked on November 14, 2012
  11. Chemistry

    In a given 1st order reaction A ---> products, the initial concentration of A is 0.40 M. What will be the concentration of A after 15 seconds if the half-life of the reaction is 3 seconds? I found the concentration to be 1.25 x 10-2 M But then how do I

    asked on February 18, 2013
  12. Physics

    You pull a sled across a horizontal frictionless patch of snow. If your pulling force is in the same direction as the sled's displacement and increases the kinetic energy of the sled by 34%, by what percentage would the sled's kinetic energy increase if

    asked on March 21, 2014
  13. Chemistry

    The decomposition of ozone may occur through the two-step mechanism shown below: step 1 O3 ----> O2 + O step 2 O3 + O ---> 2O2 The oxygen atom is considered to be: a catalyst or reaction intermediate? How am I supposed to be able to tell the difference

    asked on February 19, 2013
  14. chemistry

    A sample of propane C3H8 contains 13.5 moles of carbon atoms how many total moles of atoms does the sample contain?

    asked on March 1, 2013
  15. Chemistry

    What is the molality of an aqueous solution that is 10.0% ethanol, C2H5OH, by mass?

    asked on February 10, 2013
  16. geometry

    DEFG is an isosceles trapezoid. Find the measure of

    asked on October 20, 2011
  17. Science

    Electrical energy is required to decompose water into hydrogen and oxygen. True or False

    asked on January 29, 2018
  18. calculating statistical data

    an employee currently earning 10,85 per hour has been awarded a 3.5 percent merit raise. ehat will the employee's hourly salary be with this increase?

    asked on July 23, 2014
  19. calculus

    find dy/dx of xsiny+cos2y=cosy

    asked on December 8, 2008
  20. calculus

    how to differentiate (x^3) - 2 using [f(x+h)-f(x)]/h

    asked on July 10, 2020
  21. Math

    An object is thrown upward from the top of a 160-foot building with an initial velocity of 144 feet per second. The height, h, of the object after t seconds is given by the equation h=-16t^2+144t+160. When will the object hit the ground? The object will

    asked on December 3, 2017
  22. Chemistry

    aluminum reacts with sulfuric acid to produce aluminum sulfate and hydrogen gas. how many grams of aluminum sulfate would be formed if 250 g H2SO4 completly reacted with aluminum

    asked on February 23, 2014
  23. Chemistry

    The question is: what is the ratio [NH3/[NH4+] in an ammonia/ammonium chloride buffer solution with pH= 10.00? (pKa for ammonia=9.25) When working the problem, I tried to solve it a bit backwards, in that I plugged in each of the multiple choices I was

    asked on April 9, 2013
  24. Chemistry

    When 1.150 grams of an unknown nonelectrolyte dissolves in 10.0 grams of water, the solution freezes at -2.16°C. What is the molecular weight of the unknown compound? Kf for water = 1.86°C/m. -2.16 x m/-1.86 = 1.16 1.16/ .010 kg of water= 116 1.150/116=

    asked on February 10, 2013
  25. Chemistry

    What is the pH of a 0.1 M NaOCl solution (Ka of HOCl is 2.95 x10-8) I did: x squared/.10= 2.95x10-8 x squared= 2.95x10-9 x= 5.43x10-5 -log(5.43x10-5)= 4.27 pH However, the options I'm given are either a.) 3.74 b.) 6.47 c.) 8.23 d.) 10.27 What steps am I

    asked on April 8, 2013
  26. Chemistry

    Cyclopropane rearranges to form propene: CH2CH2CH2 --> CH2=CHCH3 by first-order kinetics. The rate constant is k = 2.74 x 10-3 s-1. The initial concentration of cyclopropane is 0.290 M. What will be the concentration of cyclopropane after 100 seconds?

    asked on February 17, 2013
  27. Math

    You have 2/3 bag of flour. Use 3/4 of the flour to make cookie dough. How much of the entire bag do you use to make cookie dough?

    asked on December 17, 2012
  28. earth science

    Please help ASAP I'm stuck!!! create an imaginary example of finding a given amount of Lokium and DOL in a rock, and then determining the absolute age of that rock. Assume that each trial represents 1,000 years.

    asked on August 13, 2019
  29. Geometry

    Two similar rectangular prisms have a scale factor of 4:1. The smaller prism has a volume of 6 cubic centimeters. What is the volume of the larger prism in cubic centimeters?

    asked on May 28, 2019
  30. Reading

    I have a journal that I have to do called "Life in Camps", it's about the holocaust. Why can I write in the journal?

    asked on January 25, 2018
  31. Physics addition of velocities

    A seagull flies at a velocity of 7.00 m/s straight into the wind. (a) If it takes the bird 17.0 min to travel 6.00 km relative to the earth, what is the velocity of the wind? (b) If the bird turns around and flies with the wind, how long will he take to

    asked on October 1, 2015
  32. chemistry

    Sodium metal is immersed into graduated cylinder that holds exactly 32.5 ml. The sodium metal used to fill the cylinder weighs 405.5 grams. Calculate the density of sodium based on the given data.

    asked on July 27, 2014
  33. calculating statistical data

    all the patients who present to the emergency service department with a suspected acute myocardial infraction (AMI) are expected to receive an EKG within 10 minutes if their arrival. of the 56 patients who had a suspected AMI during the last quarter, 32

    asked on July 23, 2014
  34. calculating statistical data

    a coding supervisor must determine the number of full time equivalents (FTES) needed to code 500 discharges per week. if it takes an average of 20 minutes to code each record and each coder works 7.5 productive hours per day, how many FTES will the coding

    asked on July 23, 2014
  35. calculating statistical data

    it takes approximately 15 minutes to code one record. How many personnel hours would be needed to code 1424 discharges for the month?

    asked on July 23, 2014
  36. Math

    Four cheeseburgers and five milkshakes cost a total of $25.50. Two milkshakes cost $1.75 more than one cheeseburger, and also find the cost of a milkshake. (A)$3.25 for a cheeseburger and $250 for a milkshake. (B)$3 for a cheeseburger and $2.90 for a

    asked on July 1, 2014
  37. physics

    Consider a toy car that you pullback to make it go forward. Is it a force multiplier or a distance multiplier? Defend your answer with the observations you could make

    asked on March 24, 2014
  38. Algebra Help

    Factor: 49^2+112r+64 =

    asked on October 11, 2013
  39. Chemistry

    Many portable gas heaters and grills use propane, C3H8(g). Using enthalpies of formation, calculate the quantity of heat produced when 15.0g of propane is completely combusted in air under standard conditions. Assume that liquid water is forming.

    asked on October 4, 2013
  40. Chemistry

    Which of the following result in buffered solutions when equal volumes of the two solutions are mixed? a.) .1 M HCl and .1 M NH4Cl b) .1 M HCl and .1 M NH3 c.) .2 HCl and .1 M NH3 d.) .1 M HCl and .2 M NH3 By def. I know that a buffed solution is made from

    asked on April 9, 2013
  41. Chemistry

    Which of the following solutes, dissolved in 1000g of water, would provide a solution would the lowest freezing point? .030 mol of BaCl2, CO(NH2)2, CaSO4, CH3COOH, or .030 mol of NH4NO3 Again, the steps needed to determine for the freezing point.

    asked on February 19, 2013
  42. chemistry

    consider the following changes at constant temperature & pressure H2O(s) --yields-- H20(l); Delta H1 H2O(l) --yields-- H2O(g); Delta H2 H2O(g) --yields-- H2O(s); Delta H3 Using Hess's law, the sum of the deltas is a. equal to 0 b. sometimes greater than

    asked on November 14, 2012
  43. math

    Use algebra pieces and mental arithmetic to determine four consecutive odd numbers who sum is 64. Sketch and label your algebra piece model and explain how you solved the problem.

    asked on June 2, 2012
  44. Algebra

    Determine whether the graphs of the equations are parallel lines, perpendicular lines, or neither. 12x + 4y = 16 5y - 22 = -15x

    asked on May 7, 2010
  45. computer science

    write a program that asks the user to enter today's sales rounded to the nearest $100 for each of three stores. the program should then display a bar graph comparing each store's sales. create each bar in the graph by displaying a row of astericks. each

    asked on April 5, 2010
  46. math

    2^100+2^100 is the answer 4^200

    asked on August 16, 2009
  47. math.....need help

    Solve the problem. An open box is to be made from a rectangular piece of tin by cutting two inch squares out of the corners and folding up the sides. The volume of the box will be 100 cubic inches. Find the dimensions of the rectangular piece of tin.

    asked on March 21, 2009
  48. social studies

    Identify one or two early signs of conflict in the colonies

    asked on January 4, 2020
  49. Math

    pls HELP Eric owns and operates the Hot Ham food truck. The expression 3.25b+2h gives the cost of b burgers and h hot dogs. What is the cost of 4 burgers and 6 hot dogs?

    asked on November 10, 2019
  50. Science

    How would you compare infrared radiation absorption and emission rates for an object at constant temperature? Thank you :)

    asked on October 26, 2019
  51. social studies

    Which sentence BEST describes the role of mercantilism in the growth of transatlantic trade during the 1600s? European countries cooperated in the shipment and exchange of goods. English settlements hoped to encourage commerce among the colonies. Colonies

    asked on September 11, 2019
  52. Math

    Ben throws a ball vertically upward from the top of a cliff. The height of the ball above the base is approximated by the model h = -5t² - 5t + 100, where h is the height in metres and t is the time in seconds. a) After how many seconds does the ball hit

    asked on May 7, 2019
  53. math

    I need help asap A solid with two parallel and congruent bases cannot be which of the following. A. cone B. prism C. cylinder D. cube My answer is cube

    asked on March 23, 2019
  54. English

    Why are the fairies singing a lullaby? A. to put their queen to sleep B. to put their babies to sleep C. to put the bird to sleep D. to show how well they sing I think the answer is B. Pls help

    asked on March 6, 2019
  55. Language arts

    Use the excerpt to answer the question 1. Which is the best paraphrase of the lines from the poem A. We are happy when the sun is shining we feel Mary when the bells ring and we sing along the sun goes down and we have to stop playing sports. B. The sun

    asked on February 12, 2019
  56. Civics

    In 2002, one U.S. dollar could be exchanged for 133 Japanese yen, and in 2011, a U.S. dollar was worth 77 yen. Based on this information, which statement is true? Demand for the yen increased between 2002 and 2011, and demand for U.S. the dollar decreased.

    asked on October 4, 2018
  57. History

    how did people react to the great depression

    asked on May 4, 2018
  58. Calculus -- STOP NOW!

    Consider the functions A(x, y) = x^2y + xy − 3xy^2, and B(x, y) = xe^xy − y (a) Calculate the x derivative of A, or Ax. (b) Calculate the y derivative of A, or Ay. (c) Calculate the x derivative of B, or Bx. (d) Calculate the y derivative of B, or By.

    asked on April 2, 2018
  59. physics

    Two stationary point charges of +61.0µC and +0.48µC exert a repulsive force on each other of 172N. What is the distance between the two charges?

    asked on February 21, 2018
  60. physics

    1) A balloon rubbed against denim gains a charge of -8.45µC. What is the electric force between the balloon and the denim when the two are separated by a distance of 4.7cm? (Assume the charges are located at a point) 2)Two identical conducting spheres are

    asked on February 21, 2018
  61. physics

    A balloon rubbed against denim gains a charge of -8.45µC. What is the electric force between the balloon and the denim when the two are separated by a distance of 4.7cm? (Assume the charges are located at a point)

    asked on February 21, 2018
  62. Reading

    Can some help me do a thesis on National Committee for a SANE Nuclear Policy?

    asked on February 14, 2018
  63. Reading

    How can I find Indirect and Direct characterization about Ponyboy in the Outsiders?

    asked on February 13, 2018
  64. Science

    Which of the following does NOT happen when vinegar and baking soda react? true or False?

    asked on January 29, 2018
  65. math

    Billions of dollars have been raised to help in the fight against malaria. The following table shows the value of some of the donations: What is the average of the values listed in the table?

    asked on January 29, 2018
  66. Reading

    Who was Reinhard Heydrich and what did he do?

    asked on January 28, 2018
  67. Reading

    Can any give a brief description of these: What was the Kristallnacht? What was like in the ghettos? What was like to lose faith during being in the camps? What was like in the transports?

    asked on January 28, 2018
  68. HELP HELp

    What can I do to successfully complete a selective Enrollment test? I haven't studied and the test tomorrow.

    asked on January 26, 2018
  69. science

    What happen to the water in the basin when you placed a drop of water?

    asked on December 7, 2017
  70. Math

    A ladder is leaning against a building so that the distance from the ground to the top of the ladder is 4 feet less than the length of the ladder. Find the length of the ladder if the distance from the bottom of the ladder to the building is 8 feet.

    asked on December 3, 2017
  71. math

    Hello i have a question.i tried it but i did not understand it. heres my question how can you describe the relative positions of p and q in the following situations? a,m(p.q)=0 b.m(p,q)0 d.m(p,q)does not exist

    asked on November 19, 2017
  72. math

    Hello i have a question.i tried it but i did not understand it. heres my question how can you describe the relative positions of p and q in the following situations? a,m(p.q)=0 b.m(p,q)0 d.m(p,q)does not exist

    asked on November 19, 2017
  73. physics

    Three forces A (30N at 35 degrees NE), B (40N at 25 degrees SW) and C (50N at SE) all act on one original point. Find the magnitude and direction measured from the positive x-axis of a fourth force F required to keep the body in equilibrium.

    asked on November 7, 2017
  74. Math

    Simplify the following expression. Write the result using positive exponents. (-2xy^-3)^-5 / (xy^-1)^-1

    asked on November 4, 2017
  75. math

    book which costs $12. He has saved one third of the amount he needs. How much money does he still need to save?

    asked on March 13, 2017
  76. Fractions


    asked on March 9, 2017
  77. Math

    robby runs for 5 minutes. He walks for 10 minutes. He runs for 7 minutes. He walks another 4 minutes. He runs again for 8 minutes and walks again for 3 minutes. what is the range of minutes robby runs?

    asked on September 20, 2016
  78. Math

    How to draw tow different parallelograms that each have an area of 4 square inches

    asked on May 12, 2016
  79. statistics

    Suppose babies born in a large Hospital have a mean weight of 4088 in a variance of 5569. if 128 babies are sample that a random from the hospital what is the probability that the mean weight of the sample babies would differ from the population mean by

    asked on March 17, 2016
  80. Math

    What is 17% of 200? .17 x 200 = 34 What is the number 200 increased by 17%? 200 x 1.17 = 234 What is the number 200 decreased by 17%? The only way I knew to do this is based on the first question - since that answer was 34, I subtracted 34 from 200 and the

    asked on January 16, 2016
  81. Physics

    A projectile with a mass of 2.50 kg is shot horizontally from a height of 15.0 m above a flat surface. The projectile's initial speed is 22 m/s. 1.How much mechanical energy does the projectile have initially ? 2.How much work is done on the projectile by

    asked on December 13, 2015
  82. Math

    I am the product of 135 and decreased by 500. who am I?

    asked on November 25, 2015
  83. algebra 2

    what is the domain in interval notation when the restrictions are x cannot = 2 and x cannot = -2? I got (-infinity, 2) U (2,-infinity) (-infinity, -2) U (-2, infinity) but my math teacher marked this as wrong

    asked on October 12, 2015
  84. chemsitry

    home / study / questions and answers / science / chemistry / make sure to answer both parts: 1)balance the following ... Your question has been posted. We'll notify you when a Chegg Expert has answered. Post another question. . Question Edit question make

    asked on September 29, 2015
  85. Physics Projectile Motion

    A projectile is launched at ground level with an initial speed of 51.5 m/s at an angle of 35.0° above the horizontal. It strikes a target above the ground 2.50 seconds later. What are the x and y distances from where the projectile was launched to where

    asked on September 29, 2015
  86. English

    What is the difference between modern fantasy and regular fantasy. Is modern fantasy merely a subgroup of fantasy? Some examples would help.

    asked on April 19, 2015
  87. english

    Researchers are LEAST likely to want to know which of the following from their sources?

    asked on March 14, 2015
  88. English

    What are the values (negative) being taught in this advertisement? The advertisement is trying to sell a military style watch. In the advertisement there are two armed soldiers in the background and appear to be situated in a war zone area. I am able to

    asked on March 1, 2015
  89. english

    What are the values (negative) being taught in this advertisement? The advertisement is trying to sell a military style watch. In the advertisement there are two armed soldiers in the background and appear to be situated in a war zone area. I am able to

    asked on March 1, 2015
  90. chemistry

    50.0 mL of a solution of HCl is combined with 100.0 mL of 1.15 M NaOH in a calorimeter. The reaction mixture is initially at 22.4°C and the final temperature after reaction is 31.2°C. What is the molarity of the HCl solution? You may assume that there is

    asked on February 28, 2015
  91. physics 105

    How many cubic feet will 44lb of CO2 occupy at STP

    asked on February 9, 2015
  92. HEALTH

    Phonology refers to the science which treats

    asked on December 17, 2014
  93. HEALTH

    Phonology refers to the science which treats A. blood disorders. B. vocal sounds. C. heart rhythms. D. nutritional deficiencies.

    asked on December 17, 2014
  94. Cardiovascular Respirtory

    A patient complains of a fast heart rate. Which diagnosis does this statement indicate? A. Arrhythmia B. Infarct C. Ischemia D. Tachycardia

    asked on December 17, 2014
  95. Cardiovascular Respirtory

    Which suffix would be used in a term pertaining to a meal? A. -EMESIS B. -RRHEA C. -TRIPSY D. -PRANDIAL

    asked on December 17, 2014
  96. Cardiovascular Respirtory

    When referring to a distended blood vessel, a doctor may use the term A. ascites. B. varicose. C. globulin. D. syncope.

    asked on December 17, 2014
  97. Cardiovascular Respirtory

    Which of the following structures are tubes? A. Cilia, adenoids, mucous, epiglottis B. Apex, base, hilum C. Frontal, maxillary, sphenoidal, ethmoidal D. Eustachian, pharynx, bronchi

    asked on December 17, 2014
  98. chemistery lab..urgent

    hi..can someone hwlp me out here on how we can calculate the moles of H2T(phthalic acid)?? its urgent for my lab this evening 1:00pm friday

    asked on September 18, 2014
  99. chemistry

    state the chemical formula of phthalic acid and calculate the molar mass using the formula.

    asked on September 18, 2014
  100. calculating statistical data

    last month, the release of information specialist received 232 requests for information. he was able to answer 176 within the specified time frame of five working days. what is the rate of compliance in the answering requests within the specified time

    asked on July 23, 2014


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