Questions Asked on
March 26, 2008

  1. chemistry

    Given: *Fe2O3(s)+3CO(s)-->2Fe(s)+3CO2(g)(delta h is -23kJ) *3Fe2O3(s)+CO(g)-->2Fe3O4(s)+CO2(g)(delta h is -39kJ) *Fe3O4(s)+CO(g)-->3FeO(s)+CO2 (delta h is 18kJ) Desired:FeO(s)+CO(g)-->Fe(s)+CO2(g) find delta h for the desired reaction. which reactions do i

    asked by tanisha
  2. chemistry proofread

    write the chemical equations for the following sentences a) Aluminum reacts with oxygen to produce aluminum oxide I put Al + O2 ----------> 2Al2O3 b) Phosphoric acid, H3PO4, is produced through the reaction between tetraphosphorous decoxide and water I put

    asked by john
  3. Physics

    A steam engine's boiler completely converts 155 kg of water to steam. This process involves the transfer of 3.5 x 10^8 J by heat. If steam escaping a safety valve does 1.76 x 10^8 J of work against the outside atmosphere, what is the net internal energy of

    asked by Lindsay
  4. physics - energy question

    A simple pendulum, 2.0 m in length, is released with a push when the support string is at an angle of 25° from the vertical. If the initial speed of the suspended mass is 1.2 m/s when at the release point, what is its speed at the bottom of the swing? (g

    asked by icy
  5. grammar

    Identify the homonym the day, month, and year / a sweet fruit with a hard seed

    asked by chase
  6. PHYSICS

    An underwater scuba diver sees the sun at an apparent angle of 45 degrees from the vertical. What is the actual angle of the sun? i don't know how to get the answer but the book says its 19.5 degrees can anyone help me?

    asked by nat
  7. Physics

    Calculate the work done by planet X on its moon. Planet X applies a force of 5.6 x 10^10 N on its moon and the moon is 4.0 x 10^8 km away from the planet and it continues to circle the planet in a circular orbit of circumference of 2.5 x 10^9 m.

    asked by Marty
  8. physics

    A child looks at his reflection in a spherical tree ornament 12 cm in diameter, and sees an image of his face that is reduced by one-fourth. How far is his face from the ornament? I don't know what I would do with the given information. I know that M=-q/p

    asked by Anonymous
  9. Physics

    Why are the steam and ice points of water better fixed points for a thermometer than the temperature of a human body?

    asked by Jim
  10. SCIENCE

    According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactnats?

    asked by SONITRA
  11. physics => really need help on 2 problems (#1)

    A house has well insulated walls. It contains a vol of 100m^3 of air at 300K a) calculate the E required to increase the T of the diatomic gas by 1.00C b) If this E could be used to lift an object of mass m through a height of 2.00m what is the mass of m?

    asked by ~christina~
  12. physics

    In a television picture tube, electrons strike the screen after being accelerated from rest through a potential difference of 25000V. The speeds of the electrons are quite large, and for accurate calculations of the speeds, the effects of special

    asked by Cindy
  13. Calc

    Find a cartesian equation for the curve described by the given polar equation. a. r=2 b. r=3sin pheta c.r^2=sin2pheta I don't understand how to solve for this, especially for r squared. Would someone plz explain how o convert to a cartesian equation. any

    asked by Jessica
  14. last chem ?

    complete each of the following synthesis reactions by writing both a word equation and a chemical equation a) sodium + oxygen---------> ___________ b) Magnesium + Fluorine ------->_______

    asked by john
  15. physics!

    An electric car accelerates for 8.0s by drawing energy from its 320-V battery pack. During this time, 1300C of charge pass through the battery pack. Find the minimum horsepower rating of the car. I need some ideas to do it!!PLEASE HELP!!!THANK YOU SO

    asked by Karmen
  16. Physics

    Two people start at the same place and walk around a circular lake in opposite directions. One has an angular speed of 1.2 10-3 rad/s, while the other has an angular speed of 3.4 10-3 rad/s. How long will it be before they meet?

    asked by Erich
  17. English expression

    Look at the bingo board. There are nine sentences in nine boxes. Look at the small bingo board over the big one. There are three sentences having shortened words in three boxes. You should write down six more senetnces containing contractions in the six

    asked by John
  18. Physics

    A boy weighing 40kg runs at 8.0m/s grabs a rope and swings of level ground. What maximum height does the child reach? How do I solve this?? it is under the conservation of energy section of work, power and energy. any help would be great! thanks

    asked by Steven
  19. Physics

    At a height of 3.00 m above the ground, a 0.500-kg ball is thrown with an initial speed of 30.0 m/s in an arc from point A to point C. When the ball is 6.00 m above the ground travelling upward, what is the speed of the ball?

    asked by Marty
  20. Social Studies- Civil War

    1) Should the North help the South or not because they lost the Civil War? 2) Should Southerners be forgiven if they swear loyalty to the U.S.? 3) When a majority of Southerners pledge their loyalty to the U.S., should they be allowed back in the Union? 4)

    asked by Joy
  21. Physics

    These are questions that follow a lab on resonance with tuning forks and a resonance tube in a water-filled graduated cylinder in part 1 (closed tube), and tuning forks with a sliding tube in part 2 (open tube). What are some applications of this study of

    asked by Mike
  22. Physics (forgot to post this question #2)

    During the compression stroke of a certain gasoline engine, the pressure increases from 1.00atm to 20.0atm. If the process is adiabatic and the fuel air mixture behaves a a diatomic ideal gas a) by what factor does the volume change b) by what factor does

    asked by ~christina~
  23. Calc

    Find a polar equation for the curve represented by the given Cartesian equation. a. y=5 b.2xy=1 I know i posted a question just for the opposite..Im confused on how to convert the other way around as well. any advice?

    asked by Jessica
  24. science

    because they are the simplest units of structure and function capable of life, cells are often called the ______ of life.

    asked by cassie
  25. history

    Were the Korean and Vietnam Wars part of the Cold War? Thanks!

    asked by Liam
  26. chemistry

    Copper (II) flouride contains 37.42% F by mass. Use this percentage to calculate the mass of flourine (in grams) contained in 35.6 g of copper (II)fluoride. --- How many grams of Cl are present in 55g of CFCl3?

    asked by Anonymous
  27. Science fair project

    Anyone know of sites on compostie softball/baseball bats?

    asked by Chey
  28. John Jay

    Where can I find the correct meaning of the following terms: Stereotype, Gender group, Pluraism, Sociology, Minority group, Assimilation, Conflict perspective, Segregation, Ethnic group, Racism, Class Subordinate group, Social construction of race, Racial

    asked by Stacey
  29. Physics

    Which object in the following pair has greater total internal energy, assuming both objects in the pair are in thermal equilibrium? a 1kg block of ice at -25 degrees Celsius or seven 12g ice cubes at -25 degrees Celsius

    asked by Jim
  30. chemistry

    How many butane molecules are present in a sample that contains 5.0 moles of butane? (Butane- C4H10) What would be the mass of 75 moles of butane?

    asked by Kate
  31. math

    A standard tip for a waiter or waitress is between 15% and 20% of the bill. If Sue wants to tip 20% of her $45.00 dinner bill, how much should she leave the waiter as a tip?

    asked by marquis
  32. algebra 1

    juan drives to work. Because of traffic conditions, he averages 22 miles per hour. He returns home averaging about 32 miles per hour. the toatle time traveled is 2 and 1/4 hours.define a variable for the time Juan takes to drive to travel to work write an

    asked by nathan
  33. Physics

    During a tennis serve, a racket is given an angular acceleration of magnitude 155 rad/s2. At the top of the serve, the racket has an angular speed of 13 rad/s. If the distance between the top of the racket and the shoulder is 1.5 m, find the magnitude of

    asked by Zach
  34. science- small intestine

    how does mechanical digestion occur in the small intestine? What three enzymes are involved in chemical digestion of small intestine and what 3 sugars do they break down?

    asked by john
  35. computers

    When I get to the series part of Microsoft Excel 2003 during graphing, what am I supposed to do?

    asked by Nina
  36. Law

    Discuss some of the possible motivations of a white-collar criminal. Why would the CEO of a Fortune 500 company embezzle money? In addition, discuss some strategies you would suggest as a business's security manager to discourage white-collar crime. Can

    asked by April
  37. Algebra

    How do I solve the equation: 4x + 3 = x = 12 using a pan balance?

    asked by Ashley
  38. Physics DC Circuit

    A |-----2 ohm r-----------2 ohm r--| | | | ___ 5 ohm r 3 ohm r - | | | ___ _ 2 ohm r - ___ | | | | I3 | | | | |-----

    asked by Bobby
  39. AP PHYSICS

    An electron and a proton are initially very far apart (effectively an infinite distance apart). They are then brought together to form a hydrogen atom, in which the electron orbits the proton at an average distance of 5.29*10^.11m. What is the change in

    asked by Becky
  40. physics

    if it costs 4.5 to 7.5 cents per kilowatt-hour (wind energy) what is the price per kW?

    asked by Tim
  41. Calc

    Find the cartesian coordinates of the following points given in polar coordinates. b. (2 rt2, 3pi/4) I cant figure this one out

    asked by Jessica
  42. chemistry 1

    k2=[H][SO4]/[HSO4] .012=(.01+x)(x)/(.01-x) Solve for x, and calculate pH where H is .01+x When I am solving for x does it become .012= .01x + x^2/ .01 -x.. what is the next step of solving for x?

    asked by lyne
  43. geography

    Need to know the principal rivers, mountains, and bodies of salt and fresh waters within and around China, Taiwan, Japan, North and South Korea. Thanks.

    asked by Dave
  44. managerial economics

    You have a friend who is always getting into trouble by taking unwise risks. What advice would you give this person? What advice would you give someone you believe to be excessively wary of risk? Also, assume you are an investor in the stock market. What

    asked by jean
  45. Physics

    The burning of gas in a car produces about 12,600 kJ/gallon of energy. If a car averages 35 km/gal when driving 90 km/hr, which requires 18.5 kW, what is the efficiency of the engine under those conditions? ...please help?

    asked by Lindsay
  46. memorization

    does anybody have any tips on memorizing things? i have to memorize one of juleit's speeches in romeo and juliet in act 2 scene 1. Please help!!

    asked by anonymous
  47. Gen Chemistry

    What is the pH ( 3 significant digits) of a 0.01 M solution of sulfuric acid? Hint is that the first ionization constant is "large", and the second is finite, and the [H+] donated by the second equilibrium depends upon the amount of [H+] already donated by

    asked by lyne
  48. Maths (coordinate geometry)

    two lines y=-2x+6 and y=1.5x+1 intersect. What is the size of the acute angle at the intersection? Ive got 59.4 degrees. Any confirmation/slight alteration?

    asked by Mikal
  49. Math

    Write each of the following ratios in simplest form. The ratio 5 3/5 to 2 1/10

    asked by Ms. Teri
  50. Spanish year 1

    Puedes jugar al tenis conmigo? No,no ___________jugar al tenis. a. juegas b.jugamos c.puedes d. se with a tilde or whatever over the e I think it says Can you play tennis with me? and the choices are you play, we play, you can, and I know how, but it seems

    asked by Alehanda
  51. Work and Family Life (WFL)

    For my Work and Family Life class I my teacher gave us a picture of a child. Everyone has a child from a different country. My girl is from South Africa. On the back of the picture it talks about the girl (age, name ect. ). Then it says the child's

    asked by Taylor
  52. Physics

    A battery with voltage drop of 120V is connected in a ciruit containing both series and parallel. Moving in a clockwise direction. R1= 3 ohms. Suddenly there is a connection of point A to point B. In between these two points is a parallel circuit with R2=

    asked by Andrea
  53. math

    How would I write the following quadratic function in standard form? The function is -(9x+2)^2+4x? What is the process for changing this to standard form?

    asked by Claire
  54. physics

    A gyroscope consists of a rotating uniform disk with a 60-cm radius, suitably mounted at one end of a 15-cm-long axle (of negligible mass) so that the gyroscope can spin and precess freely. Its spin rate is 1540-rev/min. What is the rate of precession if

    asked by kelly
  55. Science

    What solid melts at 35 degrees celsius

    asked by Alex
  56. chemistry

    Posted by lyne on Tuesday, March 25, 2008 at 11:44pm. What is the pH ( 3 significant digits) of a 0.01 M solution of sulfuric acid? Hint is that the first ionization constant is "large", and the second is finite, and the [H+] donated by the second

    asked by lyne
  57. Physical Chemistry

    Let's say we are given 1.0 mol of an ideal gas, and we are given a starting temperature, and and initial pressure the gas exerts. We are now told that the gas expands adiabatically until it reaches some other pressure, p2. How do we calculate w and dH for

    asked by AJ
  58. science

    name two factors that affect gravitional force exerted on an object?

    asked by MTH
  59. Equations and variables

    Why are variables and equations such an important part of algebraic reasoning?

    asked by Sarah
  60. Math

    Write the proportion that is equivalent to the given statement If Maria hit 8 home runs in 15 softball games, then she should hit 24 home runs in 45 games.

    asked by Ms. Teri
  61. job search

    plan for a job search by considering how you would manage the 'resume', job application letter, interview, and follow-up letter.

    asked by Anonymous
  62. ENGLISH

    I REALLY NEED HELP ON THIS. I WOULD BE GRATEFUL IF SOMEBODY COULD FIGURE IT OUT: A A A AIRBORNE AND AND AND AND AND AND BECOMES BILLS CO2 CONSTRUCTION CONVERSION DECK DISRUPTIVE DUST DUSTY EXPENSIVE FAR GO HEATING IN INSULATES LESS LOFT LOFT MOISTURE ONE

    asked by harry
  63. chemistry

    for each of the following synthesis reaction indentify the missing reactant(s) or product(s) and then balance the resulting equation a) Mg +__________ ----------> MgO b) _________ + O2-----------> Fe2O3 c) Li + Cl2 -------> _________ d) Ca +

    asked by john
  64. English expression

    The th in brother is a voiced sound, and the th in three is a voiceless sound. Do you know how to pronounce the th sound? Stick out your tongue between upper teeth and lower teeth, that is, put your tongue between your upper teeth and lower teeth and say

    asked by John
  65. math...help me! this is hard!!!!

    you have three jugs and a river of water. The jugs are known to hold exactly 3, 7, and 10 liters. How can you use these jugs to measure exactly 5 liters of water?

    asked by Kelly
  66. English expression

    Let's play the 'who is it' game, in which the appropriate person stands up. Class, first, stand up. I will ask you questions. If your answer is 'Yes, I do' or 'Yes, I am', you should remain standing. However, if your answer is 'No, I'm not' or 'No, I

    asked by John
  67. statistics

    What does the area corresponding to the critical value zcrt mean? There is a graph that has a normal bell shape curve that has a vertical arrow that intersects the x axis far from the y axis. then everything to the left of the the vertical arrow is colored

    asked by stats
  68. social studies

    what is the capital and distribution of smoothies

    asked by nya
  69. Dr.Bob

    I replied to that post from yesterday. I don't know if you saw it.

    asked by ~christina~
  70. Science 8th grade

    What is it called if you get pain in you leg when you walk and the pain stops if rest ?

    asked by Anonymous
  71. World Religion

    How does the NICA help Natives advance

    asked by Sara
  72. Physics

    The following appliances are being used simultaneously: toster oven, TV, computer, three 100 W light bulbs and an iron. Yet the circuit breaker (15 A) has not tripped. Does that necessarily mean that not all of these appliacnces are connected to a single

    asked by Andrea
  73. Algebra

    What misconceptions do children have about expressions such as 4+8 and the equal sign that can cause difficulty working with equations?

    asked by Mike
  74. Algebra

    What is algebraic reasoning? What does it mean?

    asked by Jordon
  75. chem

    What is the pH ( 3 significant digits) of a 0.01 M solution of sulfuric acid? Hint is that the first ionization constant is "large", and the second is finite, and the [H+] donated by the second equilibrium depends upon the amount of [H+] already donated by

    asked by lyne
  76. chem

    Next step, multiply both sides by (.01-x) .012(.01-x)=.01x+x^2 gather terms, put in standard binomial form, use the quadratic equation, and solve for x. is the standard binomial x^2+.022x-1.2x10^-4

    asked by lyne
  77. math

    Next step, multiply both sides by (.01-x) .012(.01-x)=.01x+x^2 is the binomial x^2 + .002x-1.2x10^-4 what is the next step is the answer -.021 and -.023 for x

    asked by lyne
  78. chem

    DrBob has given you the equation to use: k2 = [H^+][SO4^-]/[HSO4^-] and the values to substitute [H^+] = 0.01 + x [SO4^-2] = x [HSO4^-] = 0.01 - x k2 = 1.2 x 10^-2 you need to substitute these and solve for x. Remember that you are after 0.01+x [H^+] to

    asked by lyne
  79. U.S. History

    Any websites (about) or knowledge of: U.S. economic trends throughout the ‘60s, ‘70s, and ‘80s.

    asked by Saleshia
  80. Math

    what does this, ~, mean?

    asked by Chey
  81. biology

    Is a starch molecule smaller or larger than an iodine molecule?

    asked by Claire
  82. microsoft excel 2003

    How would I graph equations in Microsoft Excel 2003 and the residuals? I want to graph linear, quadratic and exponential equations but I don't know how.

    asked by Nina
  83. Marketing

    Hello, My group has been assigned to do a General Market Survey on a foreign country (we picked France). Can anyone give us some pointers on what topics/statistics to include, where to find information, anything at all? We are to use secondary data to

    asked by Chloe
  84. english

    why do mail trucks have one seat

    asked by alyssa
  85. algebra 1

    i need the rate of change for: growing from 1.4 to 1.6m in one year

    asked by taylor
  86. Communication

    What characteristics of reporting enable you to judge whether or not information is reliable? Please use examples of specific people, events, or phenomena to support your answer.

    asked by Jean
  87. ecology

    what does commensalasion mean and give an example

    asked by m
  88. science

    how does GOES help meteorologists

    asked by Anonymous
  89. Science 8th grade

    please check my answer thanks True or false Blood gains oxygen when it passes through the liver I said True

    asked by Anonymous
  90. algebra

    Explain three rules for exponents

    asked by janet barnes
  91. social studies

    Where can I find the Flags of Texas in order?

    asked by Ken
  92. algebra

    Can someone tell me if I did this the right way? It seemed easy but it makes me worried that I did it wrong. h is not equal to 0 f(x)=7x-9 f(x+h)-f(x)/h= 7(x+h)-9-(7x-9)/h= 7x+7h-9-7x+9/h= 7h/h= 7

    asked by sara
  93. history

    What does class-system and class-state mean? I can't find the meanings in the dictionary.

    asked by laney
  94. Physics

    In a certain process, 2.11x10^5 J of heat are supplied to a system and at the same time, the system expands against a constant external pressure of 6.89x10^5 Pa. Given that the temperature of the system does not change, find the increase in volume of the

    asked by Lindsay
  95. Business Studies

    hi why do brand names are dold at a higher price ? So for example even though we have two identical products , one with a brand name , and the other without , why will the brand name have a more chargable price ?

    asked by Student 1
  96. Algebra

    What misconceptions do children have about expressions such as 4+8 and the equal sign that can cause difficulty working with equations?

    asked by sarah
  97. English - Critique Essay Please

    This is how much I've done so far, not finished yet but could you see if I'm on the right track? I'm following the structure of Introduction, 3 Main Body Paragraphs and a Conclusion. Explain how the themes of prejudice and tolerance are explored in the

    asked by TP
  98. english

    can you make me a sentence out of the word interracial

    asked by chequan
  99. Apartheid

    What are the four rules of apartheid?

    asked by Cindy
  100. Math

    Marc took 3 hours (h) to mow a lawn while Angelina took 150 minutes (min) to mow the same lawn a week earlier. Write the ratio of Marc’s time to Angelina’s time as a ratio of whole numbers

    asked by Ms. Teri
  101. Math

    Find each rate. 240 pounds of fertilizer 6 lawns

    asked by Ms. Teri
  102. Math

    What are the steps to doing y = mx + b case for system of linear equations?

    asked by Selene