# 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 281-
## calculus

Question: "Plutonium isotope Pu-239 has a half-life of 24,100 years. Suppose that 10 grams of Pu-239 was released in the Chernobyl nuclear accident. How long will it take for the 10 grams to decay to 1 gram?" I know that I am suppose to use y= ye^kt , to

*asked by zak on February 26, 2009* -
## Chemistry

I have some enthalpies of formation for a reactant and transition state but calculated using different computational methods. I want to find the ratio of the forward rate constants determined using both methods but I'm not really sure how. I thought I

*asked by Alice on March 13, 2010* -
## Physics

A rock is dropped from a sea cliff and the sound of it striking the ocean is heard 3.9 s later. If the speed of sound is 340 m/s, how high is the cliff? i know you use the equation y=(initial velocity)(time) + (1/2)(acceleration)(time^2) but I'm having

*asked by Marissa on July 2, 2012* -
## Math

A football is punted. Its height, H metres is given by the quadratic relation with equation: H = -5t2 + 21t, where t is the time in seconds after the punt. I tried to do this question on a test but I just ran out of time How is the easiest and quickest way

*asked by Fred on November 20, 2015* -
## updated question

I am given this data table: Time After Consumption (min): 30, 60, 90, 120, 150, 180 Amount of Codeine in Blood (mg): 27.0, 23.5, 21.2, 18.7, 16.6, 14.5 Question: I created a scatter plot of the data. Would y=3.5/30x+30.5 be an equation to model the amount

*asked by sandy on June 2, 2014* -
## PHYSICS 2

A 2.0 kg cylinder (radius = 0.08 m, length = 0.50 m) is released from rest at the top of a ramp and allowed to roll without slipping. The ramp is 0.77 m high and 5.0 m long. (b) What is its rotational kinetic energy? ? J (c) What is its translational

*asked by kelsey on October 20, 2008* -
## Chemistry

Write a balanced equation for the following reaction. Use whole number coefficients and subscripts as appropriate. Carbon tetrachloride is an industrial liquid solvent. It is made by combining methane gas with elemental chlorine. These react to form carbon

*asked by Mike on February 1, 2016* -
## Chemistry

I will do an experiment that includes 4 grams of aluminum hydroxide and iron (III) oxide mixture, where 75% of it is Al(OH)3, and 15 ml of water and 25 ml of 2M KOH will be added and then boiled so that the Al(OH)3 dissolves. It will be filtered and then

*asked by Tiffany on March 25, 2012* -
## Math, slope

The cost of a taxi ride is $5.00 plus $0.75 for every 0.5 km. Graph this relation Identify the slope and the vertical intercept of the line. What do the represent? Write an equation relating the cost and the distance traveled. I'm not sure how I was

*asked by Kai on April 4, 2017* -
## Chemistry

How many grams of glycine amide (FM 74.08) should be used with 1.0 gram of glycine amide HCl (FM 110.54, pKa=8.20) to give 100 mL at pH 8.0? The buffer equilibrium reaction is: GlycineAmideHCl GlycineAmide + H+ which has the general form: BH+ B + H+ I'm

*asked by Ken on October 30, 2011* -
## College Chemistry

The concentration of lead ions (Pb^2+) in a sample of polluted water that also contains nitrate ions (NO3) is determined by adding solid sodium sulfate (Na2SO4) to the sample of the water. Write the net ionic equation for the reaction. Do not forget to

*asked by KELLY on September 27, 2010* -
## Chemistry

HELP PLEASE. I have no idea how to set this up. I tried using the q=mc(change in temp) equation but its not working out. A 59.8 g block of an unknown metal at 87.5 degrees Celsius was dropped into an insulated vesssel containing approximately 33 g of ice

*asked by Taylor on September 30, 2014* -
## chemistry

I have to write a balanced equation for the decompostion of solid copper (ii) sulfate to form the gaseous sulfur trioxide and solid coper (ii) oxide. I would appreciate it if you could tell me if I have written it correctly. CuSO4 >>> SO3 + CuO If I did

*asked by jazz on April 14, 2014* -
## physics

A person sitting in a chair (combined mass 80kg) is attached to a 6m long cable. The person moves in a horizontal circle. The cables angle is 62 degrees below the horizontal. What is the persons speed? Note: the radius of the circle is not 6m. I really

*asked by Todd on December 15, 2014* -
## chemistry

assuming the volume of h2so4 needed to completely neutralize naoh of concentration 0.2m is 23.50ml take the volume of base to be 2ml question write a balance equation for the neutralization calculate the concentration of the acid what indicator can be used

*asked by chiemelie on May 15, 2016* -
## 8th Grade Algebra

You know how to solve quadratic equations using algebra, graphs and the quadratic formula. Sometimes one method of solving is more convenient than another method. Describe how you would solve each equation. Give reasons for you answers. A) 16x^2 = 1600 B)

*asked by Joy on March 30, 2009* -
## chemistry

I am having a hard time with this problem. I was wondering where I went wrong. The problem says The equilibrium constant, Kc, for the reaction of H2 and N2 is 1.7×10^2 at 225 ∘C. 3H2(g)+N2(g)←→2NH3(g) If the system at equilibrium contains 0.16M H2

*asked by chelsea on November 13, 2013* -
## Math

270 tickets were sold at a school event. The total money collected is $1700, if the adults cost $10 and the student section cost $5. How many adult tickets were sold? My teacher gave this to us but he didn't explain it how. Can you help me answer this

*asked by Anonymous on September 18, 2016* -
## College Algebra

A 50 gallon barrel plumb full of water springs a leak in the bottom and leaks at a constant rate of two gallons per minute. Write an equation that relates the amount of water left in the barrel, y in terms of how many minutes have passed since the leak

*asked by Haley on November 20, 2013* -
## Maths

Solve the equation:a right pyramid with vertical height stand on rectangular base widith that measures 20cm by 14cm the hieght of the pyramid is 10cm calculate to 3 significant figure the length of the slant height , the surface area of the pyramid, volume

*asked by Thomas on February 18, 2013* -
## Calc 2

The figure shows a semicircle with radius 1, horizontal diameter PQ, and tangent lines at P and Q. At what height above the diameter should the horizontal line be placed so as to minimize the shaded area? I would post the figure but the website is not

*asked by gabby on March 28, 2016* -
## Chemistry

I have a table that has the vapor pressure of water at selected temperatures. It is converted from celsius to torr. For example: 18°C = 15.5 torr 19°C = 16.5 torr Unfortunately, the temperature I got is 18.5°C. How do I convert it to torr? The book has

*asked by Alan on March 30, 2007* -
## Math

Jasmine has taken an online boating safety course and is now completing her end of course exam. As she answers each question.,the progrss bar at the bottom She has just completed question 16 and the test bar how she is 20% of questions. How many total

*asked by Jennifer on October 29, 2013* -
## Chemistry

8.40 grams of Hydrogen gas reacts with 48.2 grams of Oxygen gas. Give the mass of the water vapor produced and the mass of the excess reactant left over. Can somebody please explain stoichiometry to me? I've failed the test and the retest. I'm usually able

*asked by Anna on November 29, 2010* -
## math

a patrol boat took 2.5 hours for a round trip 12km upriver and 12km back. the speed of the current was 2 km/h. what was the speed of the boat in still water? ps: i just need to know how to make equations from the question above. it's supposed to create

*asked by lawrence on October 15, 2010* -
## Chemmistry gas laws

CH2==Ch2(g) ----> CH4(g) + C (graphite) If the decomposition begina at 10 degrees C and 50.0 atm with a gas density of 0.215 g/mL and the temperature increases by 950K, what is the final pressure of the confined gas (ignore the volume of graphite and use

*asked by tori on October 13, 2011* -
## Trig

The original screamer radius =100 feet rotated 1 deg per sec. The engg decided to make it scarier by making it rotate 18 deg per second. Write the new equation for the vertical position of a passenger on the screamer where the domain is now the time per

*asked by skk on March 10, 2016* -
## English

1. Do-it-yourself fashion can be your solution. 2. Do-It-Yourself fashion can be your solution. 3. Diy fashion can be your solution. 4. DIY fashion can be your solution. ================================== Which one is correctly spelled?

*asked by rfvv on May 12, 2015* -
## physic

3) A shell is fired from ground level with a muzzle speed of 350 ft / s and elevation and angle of 60 . Find (a) parametric equation for the shell’s trajectory (b) the maximum height reached by the shell (c) the horizontal distance traveled by the shell

*asked by jack on April 24, 2013* -
## calculus

3) A shell is fired from ground level with a muzzle speed of 350 ft / s and elevation and angle of 60 . Find (a) parametric equation for the shell’s trajectory (b) the maximum height reached by the shell (c) the horizontal distance traveled by the shell

*asked by jack on April 24, 2013* -
## MATH

45. Express each equation in the specified form. a. y = (x – 3)² - 25 in standard form B. y = 2(x – 7)(x + 3) in standard form. C. y = - 2x² + 28x – 26 in factored form D. y = -9x² + 72x + 81 in vertex form

*asked by newbie on December 31, 2018* -
## Math

Ernesto loses 14.5 pounds in 7 months. Now he weighs 156.5 pounds. Which equation can be used to find out how much he weighed before? A. x+14.5=156.5 B. x-14.5=156.5 C. 7x+14.5=156.5 D. 7x-14.5=156.5 Is the answer B?

*asked by Gwen on September 8, 2014* -
## English

“The real world is riddled with people who have never learned to carry their own skis…” What does this quote from “Carry Your Own Skis” mean? A. A lot of people who go skiing don’t know how to carry their own skis. B. A lot of people in the

*asked by quick help needed on May 10, 2016* -
## chemistry

1) Starting with 75.00 g of 1-propanol and 75.00 g of PCl 3. Calculate the theoretical yield of 1-chloropropane. 3CH3CH2CH2OH + PCl 3 --> 3CH3CH2CH2Cl + H3PO3 Answer in terms of grams. the answer that i got is 98.12, is this right and how many sig figs

*asked by anonymous on October 1, 2011* -
## Chemistry

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

*asked by Sherryl on February 8, 2010* -
## General Chemistry

Carbonic acid forms when carbon dioxide dissolves in water. A typical can of soda contains a 0.120 M solution of CO2. Assuming that all dissolved CO2 is present as carbonic acid, and that no other substances dissolved in solution affect the pH, what is the

*asked by Erik on March 11, 2016* -
## chemistry

A student placed 11.5 of glucose () in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100.- mark on the neck of the flask was reached. The flask was then shaken until the solution

*asked by sam on January 31, 2010* -
## chemistry

Predict if a precipitate will form when 20.00 mL of the 50% saturated solution is mixed with 20.00 mL of 0.0100M of the following solutions.? the saturated solution is : BaCO3, it has the Ksp of 5.1 x 10^-9 the solubility is 7.1 x 10^-5 M. I don't know how

*asked by Crystal on February 17, 2015* -
## chemistry

A student placed 12.5 of glucose () in a 100.- volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the calibration mark on the neck of the flask was reached. The flask was then shaken until

*asked by tomi on March 12, 2009* -
## Chemistry

A student placed 12.0g 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 Steve on September 29, 2010* -
## Chemistry Help Please!!!

A student placed 17.0 g 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 Christy on June 4, 2011* -
## chemistry

n the spectroscopic analysis of many substances, a series of standard solutions of known concentration are measured to generate a calibration curve. How would you prepare standard solutions containing 10.0, 25.0, 50.0, 75.0, and 100. ppm of copper from a

*asked by mathew on October 6, 2014* -
## Algebra 2

Which describes the number and type of roots of the equation x^3 - 4x^2 + 50x + 7 = 0? a. 1 positive, 2 negative b. 2 positive, 1 negative c. 3 negative d. 3 positive How do I figure this out?

*asked by huncho jack on January 29, 2018* -
## math

John has $2.50 in nickels and dimes in his wallet. He has twice as many dimes as nickels. How many of each coin does he have? Let dimes = _____. Let nickels = _______. Equation:________________

*asked by sal on November 11, 2008* -
## algebra 2

I don't know how to do this. Which describes the number and type of roots of the equation x^3 - 4x^2 + 50x + 7 = 0? a. 1 positive, 2 negative b. 2 positive, 1 negative c. 3 negative d. 3 positive.

*asked by lizzie on August 14, 2011* -
## Algebra 2

The vertices of a feasible region are A(1,2), B(5,2), C(1,40. Write a function that satisfies each equation. a) A is the maximum and B is the minimum. b) C is the maximum and B is the minimum. c) B is the maximum and A is the minimum.

*asked by Marilu on October 18, 2012* -
## Algebra 2

The vertices of a feasible region are A(1,2), B(5,2), C(1,4). Write a function that satisfies each equation. a) A is the maximum and B is the minimum. b) C is the maximum and B is the minimum. c) B is the maximum and A is the minimum.

*asked by Marilu on October 18, 2012* -
## Algebra II

What is the equation of the line, in point -slope form, that passes through the given point and has the given slope point: (11,3); slope: 4/11 A. y-3=4/11(x+11) B. y-3=4/11(x-11) C. y-3=-4/11(x-11) D. y-11=4/11(x-3) I think it is A or B...just a lil

*asked by Cassie on December 16, 2013* -
## math

How do you solve this problem? Find the slope-intercept equation of the line that has the given characteristics. Slope 8 and y-intercept (0,5) The slope-intercept equations is y=

*asked by samuel-32 on January 13, 2011* -
## Math

Find the POI (point of intersection) for the following set of lines: y=4x-1 and y=3x+4 I know how to plot them on a graph, and find out the POI that way, but how can I find the POI through an equation?

*asked by Raluca on March 1, 2012* -
## please help meDr.Bob

I would appreciate very much If you guys could show me how to approach this problem. A solution is prepared by dissolving 10.8g of ammonium sulfate in enough water to make 100.0mL of stock solution. A 10.00mL sample of this stock solution is added to

*asked by claudia on September 23, 2007* -
## college-history

1. Should American foreign policy be based on our values and beliefs or on “real politics” (the real world)? Explain 2. Was American foreign policy, during the period 1890-1917, based upon humanitarian assumptions, bringing about a better world, or

*asked by sunshine on February 6, 2009* -
## chemistry

Rachel adds together 450.9g of a 22.0% solution of potassium carbonate and 275 grams of a 5.57m solution of Barium chlorate. How many grams of precipitate does she produce?

*asked by guadalope on May 22, 2011* -
## chemistry

What are the products formed when sulfuric acid solution reacts with potassium hydroxide(KOH) solution? Is this correct H2SO4+KOH>KS04+H30

*asked by Majra on November 20, 2007* -
## Chemistry

Give the half equations at the anode and cathode for a dilute hydrochloric acid,dilute copper chloride solution and the concentrated magnesium solution.

*asked by Eddie on May 18, 2014* -
## physics

How many grams of KOH are required to neutralized 300ml of 5.0 N HN03 solution? final answer nyan 84 grams kailangan nalang namen ng solution

*asked by jhon earl on April 10, 2012* -
## Chemistry

What will the molarity be if 12 drops of the blue dye solution is mixed with enough water to make one liter of solution (assume that 20 drops is equivalent to 1mL) Im not sure where to start?

*asked by Kristen on March 1, 2012* -
## Math

A doctor writes a prescription for 20 mg of Tobramycin antibiotic saline solution. The solution is to be injected intravenously one time a day. On hand we have a 30 mg/2 ml vial of Tobramycin.

*asked by Jenise on September 16, 2014* -
## chemistry

ahhh im confused!! Calculate the pH of a solution formed by mixing 372 mL of a solution containing 4.4 x 10-6 M NaOH with 286 mL of 6.0 x 10-2 M NaOH. Report your answer to 2 decimal places.

*asked by mark on November 16, 2007* -
## chemistry

What is the molarity of a salt solution in which 117.0 grams of salt (NaCl) is dissolved in water to give 5.00 L of solution? Show all work including units.

*asked by len on August 23, 2011* -
## difficult chemistry

Calculate the molarity of thiosulfate solution if 0.400mg of Kl03 required 100ml of the thiosulfate solution provided that excess kl and hcl were added. Who helps me

*asked by Fai on January 12, 2013* -
## corrected repost chemistry

to what volume should you dilute 125mL of an 8.00M CuCl2 solution so that 50.0mL of the diluted solution contains 5.9g CuCl2 I have a hard time determing the M1V1=M2V2 is

*asked by Monique on November 6, 2011* -
## Chemistry

1.5mL of a 0.05M solution of calcium chloride (CaCl2) was diluted with water to a volume of 10L. What was the concentration of Cl- ions in the diluted solution in ppm.

*asked by Rav on July 31, 2016* -
## Chemistry

A buffer solution of volume 100.0 mL is 0.140 M Na2HPO4(aq) and 0.120 M KH2PO4(aq). What are the pH and the pH change resulting from the addition of 55.7 mL of 0.0100 M NaOH(aq) to the buffer solution?

*asked by Jessica on October 21, 2014* -
## chemistry

You transfer a 2M stock solution of Y into a container using a slightly wet pipet containing water drops. The concentration of the transferred solution Y has a ? (lower, higher, or same) concentration than(as) 2M.

*asked by Un on April 3, 2008* -
## chemistry(rusting)

Why metal(eg. iron)placed at aqueous solution will be more easily occur rusting?Is it due to the mobile ions in the aqueous solution ?Please give me an detail explanation ,thank you.

*asked by Kong on November 4, 2011* -
## chemistry

Imagine that you have been asked to prepare 500ml of a 0.25 mol L solution of Sodium Hydroxide, NaOH. Describe how you would prepare this solution. Include any calculations that you would perform.

*asked by Dexter on October 14, 2010* -
## chemistry

Calculate the solubility (in grams per 100 mL of solution) of magnesium hydroxide in a solution buffered at pH = 12. I can get the answer in grams per mole, but i am having difficulty changing it to g/100ml.

*asked by moe on November 1, 2010* -
## chemistry

20mL ethanol(density=o.789g/mol) is dissolved in sufficient water to produce a 200mL solution. the density of the solution is 0.982g/mL. what is the molarity?

*asked by mj on March 11, 2013* -
## Chemistry

Consider the following chemical reaction 2HCl+Ca(OH) CaCl+2H2O you have a mixed solution with 20.00mL of 0.100M Ca(OH)2 solution What is the molarity of the HCl,Ca(OH)2 and CaCl2 after the reaction has stopped?

*asked by Ruffles on December 4, 2013* -
## Chemistry

An solution of antifreeze is prepared by mixing 23.0mL of ethylene glycol (d = 1.11 g/mL;molar mass = 62.07 g/mol) with 50.0 mL H2O (d = 1.00 g/mL) at 25°C. If the density of the antifreeze solution is 1.07 g/mL, what is its molaritY?

*asked by Mae on September 28, 2017* -
## Math/dilution

A powder concentrate contains 2% w/w of active ingredient. What would be the percentage concentration (w/v) of the resultant solution after a 5-g packet of powder is dissolved in enough water to make 1 quart of solution?

*asked by Anonymous on May 20, 2016* -
## chemistry

3. If 5.20 g of HCl is added to enough distilled water to form 3.00 L of solution, what is the molarity of the solution? [Use molecular weight: HCl, 36.46 amu] 5.20/36.46= 0.1426 X 3.00=0.428 M IS THIS CORRECT

*asked by Anonymous on November 8, 2014* -
## chemistry

what is the molarity of a solution prepared by dissolving 2.24 grams of NaOH in enough deionized water to obtain 500.0ml of solution?The molar mass of NaOH is 40.0g

*asked by denis on October 31, 2011* -
## chemistry

A solution is prepared by dissolving 23.7 g of CaCl2 in 375 g of water. The density of the resulting solution? is 1.05 g/ml. the concentration of CaCl2 is ________% by mass. answer: 5.94 can someone tell me the steps?

*asked by john on September 15, 2010* -
## chemistry

what is the molarity of a solution prepared by dissolving 2.24 grams of NaOH in enough deionized water to obtain 500.0ml of solution?The molar mass of NaOH is 40.0g

*asked by denis on October 30, 2011* -
## chemistry help asap please

You have been given a sample of unknown molarity. Calculate the molarity of a solution which has been prepared by dissolving 8.75 moles of sodium chloride in enough water to produce a solution of 6.22l.

*asked by David on January 9, 2017* -
## CHEMISTRY

You have been given a sample of unknown molarity. Calculate the molarity of a solution which has been prepared by dissolving 8.75 moles of sodium chloride in enough water to produce a solution of 6.22l.

*asked by Jason on January 9, 2017* -
## Chemistry

Briefly explain what the consequense would be if excess 6M NaOH solution instead of ^m NH3 solution were used to separate Fe3+ and Al3+ ions from Ca2+, Cu2+,and K+ ions at pH 9-10.

*asked by Cherie on November 27, 2012* -
## Chemistry

In a titration experiment, 15.0 mL of 0.10 M Ba(OH)2 is required to titrate a 10.0 mL of an unknown solution of HNO3. Calculate the concentration of the HNO3 solution using the data. 2HNO3 + Ba(OH)2 ® Ba(NO3)2 + 2H2O

*asked by Kevin on April 18, 2018* -
## Science- bio- Please help!!

Pretend you are a medical professional and it your job to make an I.V. solution for a patient that has a total cellular solute count of 1.19%. What would be the perfect I.V. solution to administer to your patient?

*asked by Sal on October 6, 2017* -
## chemistry

The boiling point of an aqueous solution is elevated by 0.15 degrees celcius. the change in freezing point of the solution, delta T, is? a.) -6.32 b.) 0.15 c.) -0.15 d.) 0.54 e.) -0.54 I know the answer is d, i just don't understand how to get it! thanks!

*asked by Emily on December 14, 2010* -
## science

A solution of NaOH(molar mass 40g mol-1)is prepared by dissolving 1.6g of NaOH in 500 cm cube of water.Calculate molarity(M) of the solution

*asked by Divya on April 6, 2013* -
## Chemistry

A solution was prepared by dissolving 0.817g of sulfur S8, in 100.0g of acetic acid, HC2H3O2. Calculate the freezing point and boiling point of the solution

*asked by Lauren on February 7, 2008* -
## CHEMISTRY

How many grams of NaNO2 should be dissolved in 500cm3 solution of nitrous acid (HNO2) with concentration of 0.03mol/dm3 if we wish the solution to show a pH of 3.2 Ka = 4.5 * 10^-4 M(NaNO2) = 69 g/mol

*asked by Anonymous on February 12, 2013* -
## Chemistry

Thanks in advance. A student prepared a solution of NaCl by dissolving 55.0 grams of sodium chloride in 570 mL of water. What is the percent by mass of the NaCl solution?

*asked by Dalal on February 13, 2018* -
## chemistry

A 1.0 L solution has 10.00 grams of CaCl2 dissolved in it. What is the Molar solubility of AgCl in this same solution? The Ksp for AgCl is 1.6 x 10-10 at this temperature. Hint: watch out for the common ion again.

*asked by bekah on April 12, 2014* -
## chemistry

in making a solution of an unknown solid substance to test it for the presence of ions, would it matter if you used pure water or tap water to make the solution

*asked by lester on December 17, 2009* -
## Pharmacy Calculations

6. A doctor writes a prescription for 20 mg of Tobramycin antibiotic saline solution. The solution is to be injected intravenously one time a day. On hand we have a 30 mg/2 ml vial of Tobramycin.

*asked by Jenise on September 14, 2014* -
## college algebra

Solve the system of linear equations and check any solutions algebraically. (If there is no solution, enter NO SOLUTION. If the system is dependent, express x, y, and z in terms of the parameter a.) x +2z=5 3x-y-z=12 6x-y-5z=27

*asked by Keith on April 24, 2017* -
## Math

What must be true about the solution to this system of equations? x+4y+9z = -96 -2y+9z = -47 z = -7 a) The solution will describe the intersection point(s) of the 3 graphs. b) The value of z must be -7. c) The solutions will have values for x, y, and z. d)

*asked by David on June 9, 2016* -
## chemistry

Calculate the volume of 0.1 molar hydrochloric acide solution required for titration of 20 ml of 0.5 molar sdium carbonat solution till complete reaction

*asked by Anonymous on December 21, 2010* -
## chemistry

a 340.4 ml sample of solution contains 27.4 g of cacl2. calcuate the molar concentration of calcium ion in this solution. this is what i did 27.4(110.98) =.247mol .247mol/34.4L=.726Mcacl2 is this correct?

*asked by amber on October 3, 2010* -
## Chemistry

Calculate the solubility of LaF3 in grams per liter in the following solutions. The Ksp of LaF3 is 2.01 e-19. (a) pure water (b) 0.051 M KF solution (c) 0.065 M LaCl3 solution

*asked by Tiffany on October 1, 2010* -
## Chem !!!!!!!!!!!!!!!!

a) What properties are important for a solvent to be used to extract a compound from an aqueous solution? b) When carrying out an extraction what are the advantages/disadvantages of having your extraction solution more/less dense than water? Thank you!

*asked by Jay-Jay on September 14, 2014* -
## Chemistry

The blank solution used to calibrate the spectrophotometer is 10.0mL of 0.2M Fe(NO3)3 diluted to 25.0mL with 0.1M HNO3. Why is this solution preferred to simply using de-ionized water for the calibration?

*asked by Sue on March 12, 2011* -
## Chemistry

A watch is to be electroplated with gold. - provide a solution that would make a suitable electrolyte for this cell. I'm not quite sure how to figure out what the electrolyte solution is made of. Any help you can give me would be wonderful!

*asked by Hannah on September 10, 2012* -
## Chemistry

Assuming the sample is pure sodium sulfate, how many mL of 5% BaCl2.2H20 solution would be required to precipitate the sulfate. Density of barium shloride solution of 1.00 g/mL.

*asked by Mika on October 8, 2011* -
## pre - CALCULUS

Solve the system by the method of your choice. Identify systems with no solution and systems with infinitely many solutions, using set notation to express their solution sets. x + y = -8 x - y = 14 A. {( 3, -11)} B. {( 3, 11)} C. {(x, y) | x + y = -8} D.

*asked by Ciara on April 11, 2015* -
## chemistry

If an aqueous solution of sulfuric acid (H2SO4) is neutralized by 3.20 mol of sodium hydroxide (NaOH), how many moles of acid were originally present in the solution?

*asked by Anonymous on May 10, 2011*

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