# why does the equation x^2=-9 has no real solution why does the equation x^2 = 9 has two solutions

56,329 questions, page 462
1. ## chemistry

sandstone contains 30% by weight of CaCO3, and the remaining is SiO2. 1g is dissolved in 200ml of 1 mol per litre of HCL...what will the concentration of calcium in the solution?

asked by wills on May 3, 2010
2. ## Chemistry

If 18.7 mL of 0.14 M MgCl2 are mixed with 24.2 mL of 0.52 M NaOH, what will be the final concentration of Mg2+ in solution when equilibrium is established? Assume the volumes are additive. Ksp = 1.2 10-11 for Mg(OH)2.

asked by Arturo on March 14, 2013
3. ## Math

Find the volume of revolution when the region enclosed by the functions f(x)= e^x , g(x)=e^-x ,and the two lines is revolved about the x-axis Solution V=intergrate e^2x-e^-2x dx From -1to1 1/2e^+e^-2x when you sub and cal. =0 why please help me

asked by Ali on May 11, 2016
4. ## chemistry

Describe in detail the steps one would go through to make (in reality) 500mL of a 0.1M solution of cobalt(II) chloride from a container of powdered CoSO4.7H2O

asked by Sarah on January 18, 2010
5. ## Analytical Chemistry

Calculate the number of grams needed to be dissolved and diluted to 100 ml to prepare 0.200M solution for the following substance BaCrO4. huh?

asked by Stumped on October 16, 2011
6. ## Chemistry

What mass of MgSO4 · 7H2O is required to prepare 800 mL of a 0.442MMgSO4 solution? Answer in units of g. Would you use the formula M1V1=M2V2?

asked by Mike on October 11, 2010
7. ## Chem

In a 1.0× 10–2 M solution of CH3NH3Br(aq), identify the relative molar amounts from highest to lowest for : -Br- -OH- -CH3NH3+ -HBr -CH3NH2 -H3O+ -H2O

asked by Rich on November 8, 2013
8. ## biochemistry

Calculate the pH of the resultant solution of mixing together two solutions of 2 L of 1.0 M acetic acid, 0.5 L of 1.0 M sodium acetate and then adding 8 g of solid NaOH (MW = 40.0 g/mole).

asked by Dre on January 17, 2013
9. ## Chemistry

If a chemist titrates 300.0 mL of H2SO4 with a 3.0 M solution of NaOH and requires only 3.4 mL of the base to reach the endpoint, what is the concentration of the sulfuric acid?

asked by Spacy1996 on February 17, 2012
10. ## science

What volume of 0.1M Of sulphuric acid is needed to neutralize 100cm³ of a solution of sodium carbonate of mass concentration 20gram over dm³

asked by Denis on July 26, 2018
11. ## Chemistry

You are given 350 mL a stock solution of 8.32E-03 M benzoic acid, MW = 122.125 g/mol. If the actual density should be 1.05 g/mL. What is your percent error?

asked by Udith on April 3, 2008
12. ## Analytical chemistry

Calculate to four decimal places the mass of pure dry CaCO3 required to make 1 L of a 1000 ppm Ca stock solution.

asked by Angel on October 20, 2016
13. ## Chemistry

what is the hydronium-ion concentration in a 0.35m solution of NaCO3? For carbonic acid, Ka1=4.2x10^-7 and Ka2=4.8x10^-11. (Kw=1.0x10^-14)

asked by Sara on March 22, 2013
14. ## chemistry

What volume of 0.1M Of sulphuric acid is needed to neutralize 100cm³ of a solution of sodium carbonate of mass concentration 20gram over dm³

asked by Denis on July 26, 2018
15. ## chemistry

Describe in detail the steps one would go through to make (in reality) 500mL of a 0.1M solution of cobalt(II) chloride from a container of powdered CoSO4.7H2O

asked by Sarah on January 18, 2010
16. ## Aqueous Solution

Write the positive and negative ions that result when the following compounds are dissolved in aqueous solution: Na2S (aq): (NH4)2CO3 (aq): K2SO4 (aq):

asked by Annette W on March 17, 2013
17. ## Chemistry

what is the molecular weight (G/mol) of a diprotic acid 0.43 sample that needed 35.46 ml of 0.100 M of NaOH solution to reach a phenolphthalein point?

asked by Judy on January 24, 2011
18. ## chemistry

Calculate the total amount (in moles) of Ca and Mg present in a sample of water that required 12.86 ml of 0.0005M EDTA solution to completely complex them.

asked by Ana on March 29, 2010
19. ## chem

how much of each of the following substances would you add to water to prepare 1.20L of a .85M solution? (sodium carbonate from the pure solid) ? I am stuck on how to work this one out, too. thanks

asked by mel on November 2, 2007
20. ## chemistry

What is the molarity of a nitric acid solution prepared by diluting 1.5L of 3.00M HNO3 to a total volume of 2.50L? Is the correct answer 1.8M or do I have to do more???

asked by yppum on December 13, 2009
21. ## Chemistry

Can anyone answer this question please. (Determine the concentration of an aqueous NaCl solution if 31.5 mL are required to reach the equivalence point when titrated with 25.0 mL of 0.20 M AgNO3.)

asked by John on September 19, 2010
22. ## Chemistry

The solubility of calcium sulfate at 30 degrees C is .209 g/100mL solution. Calculate its Ksp i calculated it and got 1.5 x 10 ^-2 but the program said that it was wrong if you could help explain how to do it i would appreciate it

asked by Joe on November 30, 2010
23. ## Chemistry

If 11.6 mL of 0.17 M MgCl2 are mixed with 24.9 mL of 0.58 M NaOH, what will be the final concentration of Mg2+ in solution when equilibrium is established? Assume the volumes are additive. Ksp = 1.2 10-11 for Mg(OH)2

asked by Gregory on March 14, 2013
24. ## Chemistry

You are asked to go into the lab and prepare an acetic acid-sodium acetate buffer solution with a pH of 5.43 ± 0.02. What molar ratio of CH3COOH to CH3COONa should be used?

asked by Anonymous on March 12, 2011
25. ## Chemistry

The solubility of calcium sulfate at 30 degrees C is .209 g/100mL solution. Calculate its Ksp i calculated it and got 1.5 x 10 ^-2 but the program said that it was wrong if you could help explain how to do it i would appreciate it

asked by Joe on November 30, 2010
26. ## chemistry/help

65.933grams of barium fluoride are placed into a volumetric flask,and enough water is added to make 1.500 liters of solution. calculate the molarity.

asked by JOSEPH on April 28, 2012
27. ## ap

A saturated solution of which of the follow- ing substances in water would be the best conductor of electricity? 1. CH4 2. Hg2Cl2 3. HCl 4. NH3 5. CH3COOH

asked by cheri on October 5, 2012
28. ## Chemistry

Ca(OH)2 has a Ksp of 6.5 x 10^-6. If 0.37 g of Ca(OH)2 is added to 500 mL of water and the mixture is allowed to come to equilibrium, will the solution be saturated? pls help me I stayed up all last night trying to get this one question :(

asked by Kevin pls it's due at midnight :( on November 18, 2012
29. ## Chemistry--acids

Which of the following substances can act as a Bronsted acid in aqueous solution? (Select all that apply.) NH41+ H2 O2 C4H10 H2CO3 H2SO4 H3O1+

asked by Julie on February 23, 2014
30. ## AP Chemistry- Equilibrium

If 10.0 mL of 0.18 M MgCl2 are mixed with 20.1 mL of 0.56 M NaOH, what will be the final concentration of Mg2+ in solution when equilibrium is established? Assume the volumes are additive. Ksp = 1.2 ✕ 10-11 for Mg(OH)2.

asked by Danielle on February 9, 2014
31. ## Chemistry

Calculate the boiling tempature for a solution which contains 0.325 mol of calcium phosphate (Ca3(PO4)2) dissolved into 240.0 g of water.

asked by Hailey on March 23, 2011
32. ## Chemistry

What is the molar mass of 0.500 g of unknown monoprotic acid used in titration, if 22.5 mL of 0.15 M NaOH solution was required to neutralize it? I do not need the answer, but instead an example of how to do a question just like it.

asked by Cheyenne on November 12, 2014
33. ## Chemistry

A mixture of lead, magnesium, nitrate and chromate ions are present in a solution. What will the precipitate be?** a) MgPb b) Pb(NO3)2 c) PbCrO4 d) MgCO3

asked by Andrea on May 15, 2012
34. ## SCIENCE

3) You add 36 g of MgSO4 to pure water to a final volume of 200 mL. What concentration of solution did you make ? Express the results as percentage, % (w/v).

asked by LIN on February 5, 2017
35. ## Literacy

Discuss whether or not believe teaching classes intwo languages(Billingual) is a practical solution for English Language Learners?What are the advantages and disadvantage?

asked by Anonymous on April 21, 2010
36. ## chemistry

How many grams of sucrose (C12H22O11) must be dissolved in 200 g water to make a solution in which the mole fraction of su- crose is 0.1? Answer in units of g

asked by cheri on September 16, 2012
37. ## Algebra

using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this. 3x + 24y = 24 27x – 15y = -15

asked by Miguel on March 23, 2011
38. ## math

A physician orders 2gms of an antibiotic to be placed in 1000ml of D5W. Using a constituted injection that contains 300mg/2ml, how many mls should be added to the IV solution?

asked by melissa on March 9, 2008
39. ## Health care Information System

Analyze the causes of poor quality health care data and determine the single most significant cause, as well as an innovative solution that is addressed in the text.

asked by Anita on October 16, 2012
40. ## chemistry

{V1} mL of 0.100 M HCl is placed in a {V2}.0 mL volumetric flask and water is added to bring the final volume up to 250.0 mL. What is the molarity of the dilute solution?

asked by Brendon on November 12, 2014
41. ## chemistry

Potassium nitrate weighing 15 g was dissolved in water volume of 200 cm3. Calculate the mass fraction of KNO3 in solution.

asked by michelle on November 15, 2012
42. ## science

how to remove blue color from ammonium sulfate solution which occurs dues copper content in the spent acid we generate

asked by Anonymous on July 12, 2016
43. ## chemistry

Select the answer that best describes an aqueous solution made from each of the following substances: Reference: Ref 14-4 solid aluminum chloride (AlCl3)

asked by Anonymous on October 22, 2010
44. ## chemistry

The density of a 15.00% by mass aqueous solution of acetic acid, CH3COOH, is 1.0187g/mL. What is (a) the molarity? (b) the molality? (c) the mole fraction of each component?

asked by alicia on February 11, 2008
45. ## Chemistry

Showing all calculations and specific references to the equipment needed, describe how to prepare 500mL 0.250mol/L potassium iodide(KI) solution.

asked by Robyn on June 17, 2015
46. ## Math

Suppose f(x) is a polynomial of degree of 5 and with leading coefficient 2009. Supposdm further that f(1) = 1, f(2) = 3, f(3) = 5, f(4) = 7, f(5) = 9. What is the value of f(6). The answer given in book is 241091. Please work the complete solution.

asked by Watson on April 23, 2013
47. ## Chemistry

A 0.00400- mole sample of 2-chloro-2methylpropane is added to 150Ml of water, and the mixture is stirred till the p H levels off. What is the p H of the solution?

asked by Delli on November 12, 2007
48. ## chemistry

Commercial breathalyzers contain .75 mg of K2Cr2O7, 1.5 mL of H20 and 1.5 mL of H2SO4. What is the concentraion of the dichromate in the solution?(the acid is a solvent) don't want answer just want to know how to work it out.

asked by Anonymous on February 27, 2011
49. ## chemistry

Write a procedure in a number list for how you would make 300ml of a 7% (mass/volume) aluminum chloride solution. show all calculations

asked by Anonymous on May 15, 2011
50. ## Math

Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this. 10x + 5y = 52.5 30x – 7y = 80.5

asked by Shirley on February 5, 2012
51. ## chemistry

A buffer with a pH of 3.93 contains 0.17 M of sodium benzoate and 0.32 M of benzoic acid. What is the concentration of [H ] in the solution after the addition of 0.054 mol of HCl to a final volume of 1.5 L?

asked by Kira on November 4, 2014
52. ## chemistry

The Ksp of Ag2CrO4(s) is 1.12 x 10^-12. Calculate the molar solubility of AgCrO4(s) a) in pure water b)in a solution of 0.10 mol/L sodium chromate, Na2CrO4(s)

asked by John L on April 3, 2008
53. ## AP Chemistry- Equilibrium

If 10.0 mL of 0.18 M MgCl2 are mixed with 20.1 mL of 0.56 M NaOH, what will be the final concentration of Mg2+ in solution when equilibrium is established? Assume the volumes are additive. Ksp = 1.2 ✕ 10-11 for Mg(OH)2.

asked by Danielle on February 9, 2014
54. ## chemistry

What is the molarity (mol/dm3) of a solution prepared by dilution of 0.125 moles of sodium chloride (NaCl) to 2.50x102 mL with water?

asked by pippiserra on May 5, 2014
55. ## chemistry

How much Tris-Acetate-EDTA (TAE) stock buffer (3.25 M) is required to make 400 ml of solution that has a concentrations of 250 mM? How much water?

asked by Abass on July 8, 2013
56. ## chemistry

what is the mass of the precipitate formed when 45.0 milliliters of .250 M barium chloride solution reacts with 2.00 grams of copper(II) sulfae pentaydrate?

asked by jessica on January 24, 2013
57. ## chemistry

During electrolysis of an aqueous NaOH solution in the anode, 2.8 L of Oxygen are released (under conditions considered normal). How much hydrogen is free in the cathode?

asked by wallace on December 28, 2018

Where is the vertex of the graph of y equals negative x squared plus 2 x plus 5 located? (1,5) < it's not this one (1,6) (-1,3)

asked by KIM on February 12, 2017
59. ## Chemistry

What mass of glycerin (C3H8O3), a nonelectrolyte, must be dissolved in 400.0 g water in order to give a solution with a boiling point of 103.50 C?

asked by Shawn on December 17, 2012
60. ## Math-probability

Am I right? Did I write the solution the right way or do I need to put 50% or 50%? consider the experiments involving rolling a single die once. Give the probabilities of the event described. What is P (even or prime)? Would my answer be P(e)=3/6 or P(p) =

asked by bwb on April 27, 2010
61. ## Chemistry

Repost:: sorry couldn't understand it What is the concentration of C2O4^-2 in a 0.370M oxalic acid solution? Ka1=5.6x10^-2 and Ka2=5.1x10^-5

asked by V on March 20, 2013
62. ## Chemistry

Suppose a student titrates a 10.00-mL aliquot of saturated Ca(OH)2 solution to the equivalence point with 13.65 mL of 0.0234 M HCl. What was the initial [OH − ]? What is the experimental value of Ksp?

asked by Kelly on February 5, 2014
63. ## Chemistry

At 22 °C an excess amount of a generic metal hydroxide M(OH)2, is mixed with pure water. The resulting equilibrium solution has a pH of 10.49. What is the Ksp of the salt at 22 °C?

asked by Anon on March 16, 2013
64. ## Chemistry

A solution of 10g of a nonvolatile compound in 25g of water boils at 100.78C at 1 atm. What is the molecular mass of the solute?

asked by Cielo on December 31, 2014
65. ## Chemistry

What are the molality and mole fraction of solute in a 25.5 percent by mass aqueous solution of formic acid (HCOOH)? (Explain how you got the answer please)

asked by Brianna on February 19, 2017
66. ## Chemistry

Thallium(I) hydroxide is a strong base used in the synthesis of some organic compounds. Calculate the pH of a solution containing 2.57 g TlOH per liter. I got 1.44 but I'm pretty sure that's wrong?

asked by maath on November 3, 2018
67. ## Chemistry

What is the concentration of NaNO2 if 2.13g of N2O3 is added to excess NaOH and the resulting solution is diluted to a total volume of 500.0 mL?

asked by larry on July 17, 2011
68. ## Chemistry

Describe how to prepare a 500cm3 solution of 0.2moldm-3 sodium trioxocarbonate(iv) Give the Apparatus,Method, Theory, Conclusion and precautions.

asked by Favour on October 12, 2017
69. ## college chemistry

Describe the preparation of 250cm^3 of 0.05M H2SO4 given the following stock bottle solution. %purity=98 Specific gravity=1.84 Molecular weight=98

asked by Ezinase on October 28, 2015
70. ## chem

Calculate the mass of copper and volume of oxygen (at 25 C And 760 mmHg) that would be produced by passing a current of 0.5 A through a CuSO4 solution between Pt electrodes for 3

asked by Anonymous on March 4, 2013
71. ## chemistry

Which of the following compounds would result in an exchange reaction if mixed in an aqueous solution with (NH4)2S? a. SrCl2 b. Li2C2O4 c. CH3CO2Ag d. MnSO4 I don't know what to look for.

asked by Morgan on September 15, 2010
72. ## Chemistry AP

How many moles of sodium hydroxide would have to be added to 125 mL of a 0.411 M nitrous acid solution, in order to prepare a buffer with a pH of 2.990?

asked by Jessica on November 11, 2009
73. ## chemistry

an aqueous solution is formed b adding 50.1 g sucrose to 200.0g water. what is boilin point in degrees celcius of sgar soulution.

asked by Anonymous on February 9, 2010
74. ## Chemistry 1

What is the minimum amount of a 6.0 M solution of sulfuric acid necessary to produce 25 grams of hydrogen gas if the molar ratio in the chemical reaction is a 1:1

asked by Jordan on October 21, 2010
75. ## chemistry

What is the molarity (mol/dm3) of a solution prepared by dilution of 0.125 moles of sodium chloride (NaCl) to 2.50x102 mL with water?

asked by Josh on May 5, 2014
76. ## chemistry

At –14.5 °C (a common temperature for household freezers), what is the maximum mass of aspartame (C14H18N2O5) you can add to 3.00 kg of pure water and still have the solution freeze

asked by Anonymous on July 16, 2012
77. ## chemistry buffer

Calculate the amount of sodium acetate to be added to 100ml of a 0.100M acetic acid (pka=4.76) solution to obtain a buffer of pH 4.50.

asked by Mansura on April 24, 2016
78. ## AP Chemistry

We drop 17.3 grams of magnesium into 435 mL of a 2 M HCl solution. What is the maximum volume of dry hydrogen that could be produced by this reaction at STP?

asked by Anonymous on October 15, 2013
79. ## Help pls.

Compute the acceleration of the block sliding down a 30 deg inclined plane if the coefficient of kinetic friction is 0.20. Show solution pls.

asked by Yan-yan on August 23, 2014
80. ## chemistry

Reaction with Felings solution,if adding 2-butanol to potassium dichromate, in this experiment what spiecfic organic product would be form and structure.

asked by Hasina on March 25, 2007
81. ## Chemistry

How do you set up this problem? Calculate the volume , in ml of a 0.150 M NaOH soulution needed to neutralize 25.0ml of a 0.288 M HCl solution?

asked by Catherine on November 23, 2014
82. ## Chemistry

Which two processes are at equilibrium in a saturated sugar solution? ionization and recombination evaporation and condensation decomposition and synthesis dissolution and crystallization

asked by Sayum on April 2, 2018
83. ## Chemistry

FeSCN2+ -> Fe3+ + SCN- Solution is initially dark red. If some Ag+ is added to form AgSCN. what happens to position of equilibrium? what happens ot the color?

asked by Grace on February 8, 2011
84. ## aqueous solution

Write the positive and negative ions that result when the following compounds are dissolved in aqueous solution: Na2S (aq): (NH4)2CO3 (aq): K2SO4 (aq):

asked by Annette W on March 21, 2013
85. ## Chemistry II

Determine the grams of solute required to prepare 0.5 m solution HC2H3O containing 750 g of water. Make sure to show your work. **(Thanks for helping by the way.)**

asked by Chrystal on January 22, 2014
86. ## Chemistry

Calculate the mass of copper and volume of oxygen (at 25 C And 760mmHg) that would be produced by passing a current of 0.5 A through a CuSO4 solution between Pt electrodes for 3 hours.

asked by Fahmi on February 3, 2012
87. ## algebra

Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this. -x – 8y = 43 4x + 32y = 172

asked by Joel on February 22, 2011
88. ## ap chemistry

We drop 50.5 grams of magnesium into 572 mL of a 3 M HCl solution. What is the maximum volume of dry hydrogen that could be produced by this reaction at STP?

asked by Anonymous on April 28, 2013
89. ## physical science chemistry

calculate the mass of sodium nitrate needed to make 550 ml of solution of concentration 0;2 mol.dmc to the power of minus 3

asked by Thuba on April 8, 2013
90. ## Math ( i just need these two to finish my workshet

Show the solutions of 1. If a = 4, b = 3, and A = 36o. 2. If a = 3, b = 4, and A = 48.59o Finding a "solution" means solving for all missing sides and angle measures in each triangle.)

asked by Tony on July 28, 2012
91. ## Chemistry

How many grams of a sodium salt would you need to prepare 500 ml of a buffer at pH = 3.29, using 0.100M solution. (Use 3 sig fig , atomic wts to whole number)

asked by John on April 9, 2018
92. ## Chemistry

The density of a 15.00% by mass aqeous solution of acetic acid is 1.0181g/mL What(i)the molarity (ii)molality (iii) the mole fraction of each component?

asked by Wendy on August 13, 2018
93. ## Chemistry

Given 100 mL of pure water at 40C, what volume of a solution of hydrochloric acid, with a density of 1.175 g/mL and containing 34.4% HCI by weight, could be prepared?

asked by Sidney on May 22, 2016
94. ## chemistry

How much heat is gained in joules by the water where a chemical reaction takes place in 100 mL aqueous solution and has a temperature increase of 12 C

asked by Darryl on November 18, 2010
95. ## chemistry

Calculate the molarity of a solution made by adding 47.2g of NaNO3 to a flask and dissolving it with water to create a total volume of 1.80L .

asked by Sam on April 1, 2015
96. ## Chemistry

A current of 4.00 A is passed through a solution of AgNO3 for 1.00 hr. What mass of silver is deposited at the cathode? (In grams) Use Faraday's constant F = 9.65x10^4 C/mol

asked by Jon on January 11, 2015
97. ## science

During standardization of permanganate solution using sodium oxalate, can the titration between Mno4- and C2o42- at 25degree celcius be perform? state the reasons.

asked by Angela on October 29, 2013
98. ## Chemistry

What mass of sodium benzoate should be added to 160.0mL of a 0.17M benzoic acid solution in order to obtain a buffer with a pH of 4.30?