1. 4 grade math

    what are two addition problems with the answer of -30

    asked by priscilla on April 15, 2010
  2. social studies

    Did the aztecs and america have problems between each other

    asked by Nyan on February 21, 2017
  3. Math

    System of equations 1). 2/5x + 5/6y=6 Y/3=x/2+9. 2).4x+2=3y+5 2y-1=x+2 These are my last two problems and I can t get it Thanks for the help

    asked by Alena grace on February 3, 2014
  4. Math

    What does the y = in exponential problems? Y2 × y4 the exponents are the 2 and 4

    asked by Janica on February 7, 2017
  5. science

    what problems are acid precipition associated with

    asked by kenya on June 3, 2011
  6. Intermediate math

    I have to factor these two problems but am having some difficulties X^3y^6-64 & (x+y)^3+(x-y)^3

    asked by April on September 13, 2015
  7. Science - Physics - Optical Fibres

    What problems are associated with optical fibres?

    asked by Barbie on October 4, 2010
  8. social studies

    what are some problems that exist within Martinique

    asked by fardin on June 1, 2014
  9. math

    Can anyone give me any word problems

    asked by Nyan on March 13, 2017
  10. math

    show the work for these problems 4 2/3-1 1/6 = and 10 1/2-6 2/5=

    asked by sherm on February 17, 2014
  11. enviromental science

    what are three ocean resource problems

    asked by Michelle on October 19, 2008
  12. Math Last one

    I am down to 5 out of 49 problems that I can't figure out. Help is very much appreciated. Thanks ! c^2 +8c +15 =0

    asked by Christy on July 21, 2010
  13. math/algebra

    I need help with this problems graph inequalities 3x-4y

    asked by jaysgyrl on September 6, 2007
  14. math

    if x is zero, are the following problems equal? 9x-3x-4, 12x-4, 5x+x-4?

    asked by kyle on April 28, 2017
  15. algebra

    How do i solve these kind of problems? -ã((7c)^2)

    asked by Jackster on February 28, 2011
  16. math

    how do i work the problems 2 20-7=18-___

    asked by kiristen on December 12, 2013
  17. algebra

    Need help with 3 problems on page 167 X+2y=6 5x+3y=2 4x-3y=-20 -x-8y=5 5x+6y=-11 3x+y=-4

    asked by dee on May 14, 2013
  18. geography

    what are the problems caused by drought?

    asked by kirubel on May 18, 2010
  19. englis

    having problems with a "gerund" worksheet

    asked by lulu on May 22, 2013
  20. math

    how do I solve problems like this? 64x1 7/24

    asked by jessica on July 19, 2017
  21. Algebra

    I am having problems with polynomial functions. f(x)= (x-3)(x+2)(x+4)

    asked by Ian on August 29, 2010
  22. Social studies

    What are two organisation of environmental problems and how it help

    asked by Saytu on April 25, 2012
  23. Confused

    Find the slope of these problems y=-4x+3 and x+6y=12

    asked by Felicia on June 13, 2008
  24. math

    Can anyone give me any word problems

    asked by Nyan on April 9, 2017
  25. reading

    what problems did amelia earhart have

    asked by michaela on April 20, 2010
  26. Math

    Please help. Are the 2 problems correct? _ __ .52 < .52 .7 1/3 > .713

    asked by Adella on November 6, 2015
  27. Algebra 8th

    I Was Looking at The ProBlems of Paloma and i thing we have the same HW. so can You HelP Me On This? n=5.75

    asked by ricardo on August 31, 2010
  28. geometry

    how to solve sequence problems

    asked by shanda on June 2, 2008
  29. To Reiny

    Can you please help me with those problems i answered you back thanks! :)

    asked by Jen on July 23, 2011
  30. Pre-Algebra

    I am having problems with graphing inequalities how do you do them for example x + y < 3 or x> -2

    asked by Kate on May 18, 2008
  31. civic

    what are the local civic problems

    asked by mohammed on January 27, 2016
  32. math

    24-(8/2)+6= (8/4)*(7*0)= 5*(6-3)+ 10/(8-3)= What order do you use to solve these problems

    asked by Anonymous on November 8, 2012
  33. Physics

    I have some physics problems that I would like to get checked please?

    asked by Jesse on September 23, 2007
  34. math, answer please!

    I don't understand how you do these 2 problems. (p-7)(p+8) & (-7+p)(8+p)

    asked by Angelica on April 18, 2010
  35. Probability problems

    I need help with two word problems that have to do with probability. Can someone please help me?

    asked by Gayla on May 21, 2008
  36. math

    Can i get help in multiply and division problems?

    asked by henry on December 5, 2008
  37. chemistry

    1. When performing this experiment, a student mistakenly used impure KHP to standardize the NaOH solution. If the impurity is neither acidic nor basic, will the percent by mass of acetic acid in the vinegar solution determined by the student be too high or

    asked by anonymous on March 23, 2014
  38. MATH - immediate help needed!

    Please provide the solution to the below problems: In a certain state lottery, a player selects four different numbers from 1 through 30. Find the probability that a single choice of four numbers wins the lottery, assuming the order of the numbers is not

    asked by Vivan on February 2, 2013
  39. Chemistry

    List the grams of bleach solution necessary to provide 0.931g of NaClO(laundry bleach is 8.25% NaClO by weight) and the mL of bleach solution that contains the necessary amount... NaClO=74.442 g/mol. Need 0.931 grams of NaClO. Density of NaClO solution is

    asked by Niki on February 10, 2016
  40. chem

    part 1 When 0.633 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 103C is observed. Assume the solution's final volume is 200.0 mL, the density is 1.00 g/mL, and the heat capacity is 4.184 J/gC. (Note: Pay attention to

    asked by Anonymous on May 14, 2010
  41. Science

    why does all the information available state that the maximum amount of table salt that can dissolve in water is: 36-39 g/100 ml @ 20 degrees Celsius. i put 35.7 g in 100 ml over a week ago, check it 3 times daily and a lot of it never dissolved. the water

    asked by Eric on January 11, 2017
  42. chemistry

    Assume that it is necessary to determine the [FE^3+ in a solution that may be 0.0001 to 0.0005 M range . Outline the spectrophotometric method that would accurately give the required data. Be spectific about the solutions that you would use. I know I have

    asked by jxv on November 13, 2016
  43. help with websites and introduction asap plz

    i have to write an essay on this topic: The constitution was an attemt to addrss the problems that existed under the Articles of Confederation. A) list and explain three problems of decentralized power under the articles of confederation. for each problem

    asked by haley on July 27, 2006
  44. physics

    You observe someone pulling a block of mass 48 kg across a low-friction surface. While they pull a distance of 3.0 m in the direction of motion, the speed of the block changes from 4.9 m/s to 7.7 m/s. Calculate the magnitude of the force exerted by the

    asked by Amelie on April 14, 2011
  45. Physics

    You observe someone pulling a block of mass 48 kg across a low-friction surface. While they pull a distance of 3.0 m in the direction of motion, the speed of the block changes from 4.9 m/s to 7.7 m/s. Calculate the magnitude of the force exerted by the

    asked by Amelie on April 14, 2011
  46. chem help

    You need to produce a buffer solution that has a pH of 5.08. You already have a solution that contains 10 mmol (millimoles) of acetic acid. How many millimoles of acetate (the conjugate base of acetic acid) will you need to add to this solution? The of

    asked by chem on February 28, 2009
  47. Chemistry

    Consider the titration of 100.0 mL of 0.260 M propanoic acid (Ka = 1.3 ✕ 10−5) with 0.130 M NaOH. Calculate the pH of the resulting solution after each of the following volumes of NaOH has been added. (Assume that all solutions are at 25°C.) (a)

    asked by Rina on December 8, 2013
  48. algebra

    To solve the inequality -1/2 k is greater then or equal to -5, Danny multiplied both sides by the reciprocal of -1/2 . His solution was k is greater then or equal to 10.What mistake did he make? Danny checked his solution, but his check did not let him

    asked by lala on December 9, 2010
  49. Chemistry

    Metal cations can act as lewis acids in water to produce an acidic solution even though the metal ion contains no hydrogen. Water hydrates the ions in solution and partial loss of electrons from water allows hydrogen ion to be lost What is the pH of a

    asked by Jude on April 16, 2011
  50. Chemistry

    Henry constant for the dissolving of nitrogen in water was reported as 7e-4 mol/Latm at 20 deg Celsius. What is the value of the equilibrium constant, K, at 20 deg Celsius for the process N2(g0)=N2(aq). If the amount of nitrogen in aqueous solution is .1

    asked by Anonymous-PLEASE HELP!! on February 3, 2014
  51. Chemistry

    Henry constant for the dissolving of nitrogen in water was reported as 7e-4 mol/Latm at 20 deg Celsius. What is the value of the equilibrium constant, K, at 20 deg Celsius for the process N2(g0)=N2(aq). If the amount of nitrogen in aqueous solution is .1

    asked by Anonymous on January 31, 2014
  52. Chemistry

    A 0.150 M solution of nitrous acid (HNO2) is made. Ka = 4.5 x 10-4 1. Show the equilibrium which occurs when this acid is dissolved in water. 2. What is the pH of the solution? Show all work clearly. 3. 100.0 mL of the solution is titrated against 0.150 M

    asked by Tiri on April 6, 2012
  53. Chemistry

    A 0.150 M solution of nitrous acid (HNO2) is made. Ka = 4.5 x 10-4 1. Show the equilibrium which occurs when this acid is dissolved in water. 2. What is the pH of the solution? Show all work clearly. 3. 100.0 mL of the solution is titrated against 0.150 M

    asked by Tiri on April 6, 2012
  54. Chemistry Homework Help Please!

    1.) Quantify the pH for a solution prepared by dissolving 0.050 moles of Acetic Acid (CH3COOH) and 0.20 moles of Sodium Acetate (CH3COONa) in water and adjusting the volume to 500 mL. The pka for Acetic Acid (CH3COOH) is 4.75. 2.) Should 0.010 moles of

    asked by Always on November 24, 2014
  55. CHEMISTY HOMEWORK HELP ASAP

    1.) Quantify the pH for a solution prepared by dissolving 0.050 moles of Acetic Acid (CH3COOH) and 0.20 moles of Sodium Acetate (CH3COONa) in water and adjusting the volume to 500 mL. The pka for Acetic Acid (CH3COOH) is 4.75. 2.) Should 0.010 moles of

    asked by Always on November 24, 2014
  56. chemistry

    Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added. Calculate the pH of the solution after 500 mL

    asked by Jasmine on January 31, 2017
  57. chemistry

    Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added. Calculate the pH of the solution after 500 mL

    asked by Crystal on February 3, 2017
  58. Chemistry

    The enthalpy of solution is the amount of energy absorbed or released when a solute is dissolved in a solvent. Suppose a 650 g ‘cold pack’ drops in temperature from 24 Celsius to -15 Celsius when its constituents mix. Assuming the specific heat of this

    asked by Bobby on May 1, 2019
  59. Pre - Cal

    1. Find the vertex of the parabola: 4y^2+4y-16x=0 2. Find an equation of the parabola, opening down, with vertex (-3,1) and solution point (4,-5). 3. The main cables of a suspension bridge are 20 meters above the road at the towers and 4 meters above the

    asked by Veronica on May 5, 2014
  60. chem

    The pH of saturated Sr(OH)2 is found to be 13.12. A 15.0ml sample of saturated Sr(OH)2 is diluted to 250.0ml in a volumetric flask. A 15.0ml sample of the diluted Sr(OH)2 is transferred to a beaker, and some water is added. The resulting solution requires

    asked by tomi on April 2, 2009
  61. chemistry

    A 0.094 g of CuSO4*5H20is dissolved and diluted to the mark in a 500.0-mL volumetric flask. A 2.00-mL sample of this solution is transferred to a second 500.0-mL volumetric flask and diluted. What is the molarity of CuSO4 in the final solution? To prepare

    asked by Anonymous on August 29, 2011
  62. math

    A 9 percent salt-water solution is mixed with 4 ounces of an 18 percent salt-water solution in order to obtain a 15 percent salt-water solution. How much of the first solution should be used? 1 ounce 2 ounces 3 ounces 4 ounces Explain your answer.

    asked by M.A. on August 31, 2010
  63. Algebra

    I am having problems figuring out some of my word problems for this week. Could someone check these? The equation y=-1777x+27,153 can be used to predict the number of gun deaths in the U. S. x years after 2000, that is, x=0 corresponds to 2000, x=2,

    asked by Samantha on January 7, 2009
  64. Science

    1. You observe two beakers containing clear liquid and ice cubes. In the first beaker, the ice cubes are floating. In the second, the ice cubes are on the bottom of the beaker. Write a hypothesis to explain the difference in your observations about the two

    asked by Lyric on September 17, 2012
  65. College Chemistry - Science

    In an acid-base experiment at 25.0°C, a sodium hydroxide solution was standardized against KHP. The average value for the concentration of the sodium hydroxide solution was calculated to be 0.0125 M. This solution was used to titrate the phosphoric acid

    asked by Anonymous on March 2, 2014
  66. Chemistry - Science

    In an acid-base experiment at 25.0°C, a sodium hydroxide solution was standardized against KHP. The average value for the concentration of the sodium hydroxide solution was calculated to be 0.0125 M. This solution was used to titrate the phosphoric acid

    asked by Anonymous on March 2, 2014
  67. Chemistry

    A 100.0mL solution containing aqueous HCl and HBr was titrated with 0.1290M NaOH. The volume of base required to neutralize the acid was 47.56mL. Aqueous AgNO3 was then added to precipitate the Cl- and Br- ions as AgCl and AgBr. The mass of the silver

    asked by Melia on November 19, 2012
  68. Chemistry!!!!!! Please help immediately!!!

    Please show me step by step. Thank you. One commercial method used to peel potatoes is to soak them in a solution of NaOH for a short time, remove them from the NaOH, and spray off the peel. The concentration of NaOH is normally in the range of 3 to 6 M.

    asked by Lilyyyyyyyyyyyy!!!! on March 24, 2013
  69. Chemistry

    I am hoping to receive help getting started with this problem, possibly some steps in the correct direction. Here is the question: 5.0mLs of a 6.0M solution of HCl was transferred to a 1000ml volumetric flask and diluted to volume w/ water. 50mLs of this

    asked by Juggernaut on June 9, 2009
  70. Chemistry

    A sample of g 0.2050 oxalic acid (4.2 H2C2O H2O) required 25.52 mL of KOH solution to complete the neutralization according to rea tion: HOOCCOOH + 2 KOH + KOOCCOOK ↔ H2O Which the concentration in mol L-1 of this KOH solution? A sample of an unknown

    asked by Michaela on April 13, 2016
  71. Linear Algebra

    Hello ! i try to solve Linear algebra 2 questions(but need them be written properly as mathmatical proofs) Having A matrice nXn: 1)proove that if A^2=0 the columns of matrice A are vectors in solution space of the system Ax=0 (x and 0 are vectors of

    asked by Anatoly Z on January 11, 2009
  72. Religion

    If you were to learn about a new religion, what are the ten questions you would ask a person from that religion? Thank you for using the Jiskha Homework Help Forum. Without knowing what that new religion is, assuming it is already an established one, it is

    asked by Dena on February 1, 2007
  73. chem

    The units of parts per million (ppm) and parts per billion (ppb) are commonly used by environmental chemists. In general, 1 ppm means 1 part of solute for every 106 (one million) parts of solution. Mathematically by mass: ppm = µg solute / g solution = mg

    asked by mel on November 3, 2007
  74. Science (physics)

    The driver of a car travelling along a straight road with a speed of 72km/hour observe a signboard which give a speed limit to be 54 km/hour. The sign board is 70m ahead when the driver applies the break calculate the acceleration of the car which will

    asked by Garima on December 23, 2016
  75. chem

    1.Aqueous solutions of sodium and copper (II) chloride are mixed together. which statement is correct? a. both NaCl and CuS will precipitate from solution b. no precipitate will form c. CuS will precipitate from solution d. NaCl will precipitate from

    asked by audrianna on December 3, 2009
  76. Chemistry

    I have to match the items to the statements below, and I'm stuck! A Dilute B Unsaturated C Saturated D Supersaturated 1. Sodium acetate solution after the excess solute fell out of solution. 2. There is visible solute on the bottom of the container. 3. The

    asked by Lindsay on April 24, 2007
  77. Chemistry?

    You move a bar magnet two inches through a coil of wire. What do you observe in a galvanometer hooked up to the coil? The pointer moves one direction and then stops in that position. The pointer moves one direction and then goes back to center. The pointer

    asked by Bleaktuber on February 18, 2019
  78. SPELLING

    HOW DO YOU SPELL ARGUEMENT IS THAT THE CORRECT SPELLING? argument thank you I feel so dumb sometimes If you have a spell checker on your application, this can help you more quickly. As some extra information, there is a difference between being ignorant

    asked by patti on November 21, 2006
  79. chemisrty

    Q1) A solution of ascorbic acid (C6H8O6, Formula mass = 176 g/mol) is made up by dissolving 80.5 g of ascorbic acid in 210 g of water, and has a density of 1.22 g/mL at 55 oC. Calculate the following: a) the mass percentage of ascorbic acid b) the mole

    asked by lyan on January 16, 2012
  80. Math... please help me

    Please can you help me to solve and get the solution for these problems. how to get the solution please help me question: 1.Find the price of a 10% coupon bond with 10 years to maturity if interest rates: A) increase by 1% B) decrease by 1% C) increase by

    asked by jessie on September 11, 2011
  81. College Chemistry

    A student placed 14.0g of glucose (C6H1206) in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100.-mL mark on the neck of the flask was reached. The flask was then shaken until

    asked by Christian Gillard on February 21, 2010
  82. College Chemistry

    A student placed 14.0g of glucose (C6H1206) in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100.-mL mark on the neck of the flask was reached. The flask was then shaken until

    asked by Christian Gillard on February 21, 2010
  83. chemistry

    A total of 2.00 \rm mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 115 g of solution. The reaction caused the temperature of the solution to rise from 21.0 to 24.7 ^\circ \rm C. What is the enthalpy of this

    asked by Anonymous on October 2, 2011
  84. physical science

    To create a supernaturated solution, a student heats a beaker of water on a hot plate and adds sugar until no more sugar will dissolve. The student then strains the solution through a funnel using filter paper and allows the solution to cool. Name two

    asked by 132 on January 11, 2011
  85. College Chemistry

    A student placed 14.0g of glucose (C6H1206) in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100.-mL mark on the neck of the flask was reached. The flask was then shaken until

    asked by Christian Gillard on February 21, 2010
  86. Physical Science

    To create a supernaturated solution, a student heats a beaker of water on a hot plate and adds sugar until no more sugar will dissolve. The student then strains the solution through a funnel using filter paper and allows the solution to cool. Name two

    asked by SHAZAM on January 12, 2011
  87. chemistry Who clearlyexplain step by step

    1g of mixture na2c03 and k2c03 was made upto 250ml is aqueous solution. 25ml of this solution was neutralized 20ml of hcl of unknown concentration. The neutralized solution requires 16.24ml of 0.1N agn03 for precipitation Calculate A) the k2c03 is mixture

    asked by Ferda on January 18, 2014
  88. chem

    determine the osmotic pressure of the solution at STP. (Assume these solutions behave ideally.) a)0.116 mol fraction glucose (C6H12O6) in water (Assume the density of the solution is 1.02 g/mL.) b)0.0948 mol fraction NaCl in water (Assume the density of

    asked by Rukky on January 26, 2011
  89. Chemistry

    7) A 3.33 g sample of iron ore is transformed into a solution of iron (II) sulfate. And this solution is titrated with 0.0150 M potassium dichromate. If it requires 41.40 mL potassium dichromate solution to titrate the FeSO4, find the percentage of iron in

    asked by CHIPNDALE on November 21, 2015
  90. Chemistry

    1.630 g of iron ore is dissolved in an acidic solution. This solution is titrated to a pink endpoint with 27.15 mL of a 0.020 M KMnO4 solution. a. How many moles of MnO4- ions were consumed? b. How many moles of Fe2+ were in the iron ore sample? c. What is

    asked by Ray on September 8, 2014
  91. CHEMISTRY

    In a chemically active extraction, a three-component mixture of acetylsalicylic acid, acetaminophen, and caffeine in ethyl acetate solution is separated into its individual components first by extraction with a pH 8 buffer solution, then a subsequent

    asked by Gabby on September 9, 2012
  92. Chemistry: Raoult's Law

    If 0.380 mol of a nonvolatile nonelectrolyte are dissolved in 3.00 mol of water, what is the vapor pressure P(H2O) of the resulting solution? The vapor pressure of pure water is 23.8 torr at 25 C. I got this answer correct: 21.1 torr A solution is composed

    asked by Sar on September 2, 2010
  93. Chemisty

    A 2.5 L volume of sodium hydroxide solution was prepared. The titrant was standarized against primary standard oxalic acid dihydrate, H2C2O4*H2O(molar mass is 126.06) if a 0.4774g sample of the prmiary standard consumed 31.94mL of the base solution in

    asked by Brittany on May 9, 2012
  94. chemistry

    Online chemistry lab preparing standards help? I was told to prepare some standard for a chemistry lab and here where the instructions: Obtain a solution of known phosphate concentration. In this lab we will use (1.e-002M) potassium dihydrogen phosphate,

    asked by Gweedo8 on July 1, 2009
  95. College Chemistry

    Calculate the concentrations of the following solutions, assuming the volumes are exact measurements: a. 18.64g of sodium hydroxide in 350mL of solution b. 8.97mL of 18M hydrochloric acid in 250mL of solution

    asked by Bekah on October 4, 2011
  96. chemistry

    Moles chemistry? Calculate the mass of solute required to prepare ib the solution 200cm^3 of solution containig 0.50 mol dm ^-3 cl-iond prepared by dissolving cacl2.6h2o in water.

    asked by joanna on December 8, 2016
  97. chemistry

    When .03 mol Na is added to 100g of water, the temp. of the resulting solution rises from 25C to 37.9C. If the specific heat of the solution is 4.18 J/(g C), calculate delta H for the reaction, 2Na(s) + 2H2O(l) --> 2NaOH(aq) + H2(g)

    asked by Amanda on July 7, 2010
  98. Chemistry

    How many grams of KNO3 are needed to make 450 mL of a solution that is to contain 5.50 mg/mL of potassium ion? Calculate the molarity of the solution. ______g ______M i honestly don't know where to start, but i know that M=mol/L will be involved

    asked by Sam on May 10, 2011
  99. chemistry

    a solution (S) is prepared by dissolving 50.0 g calcium chloride in 250 ml volumetric flask wich is then filled with distilled water up to the line mark. calculate the molar concentration of solution (S)

    asked by alia on March 10, 2013
  100. Chemistry

    Suppose 49.6 mL of 0.242 M CoCl2 solution is added to 23.8 mL of 0.361 M NiCl2 solution. Calculate the concentration, in moles per liter, of each of the ions present after mixing. Assume that the volumes are additive. I'm not sure what to do! Thank you!

    asked by Michael on May 9, 2010