Sunday

November 23, 2014

November 23, 2014

Number of results: 26,070

**Chemistry**

The Question Is: "A student weighs 0.347 g of KHP on a laboratory balance. The KHP was titrated with NaOH and the concentration of the NaOH determined to be 0.110 M. For the second titration, the student correctly diluted 6 M HCl from the reagent shelf using a graduated ...
*October 20, 2010 by James*

**College Chemistry**

"A student weighs 0.347 g of KHP on a laboratory balance. The KHP was titrated with NaOH and the concentration of the NaOH determined to be 0.110 M. For the second titration, the student correctly diluted 6 M HCl from the reagent shelf using a graduated cylinder to obtain ...
*October 20, 2010 by James*

**statistics**

Suppose that the weights of airline passenger bags are normally distributed with a mean of 48.08 pounds and a standard deviation of 3.13 pounds. A)Let X represent the weight of a randomly selected bag. For what value of c is P(E(X) - c < X < E(X) + c)=0.84? Give your ...
*February 19, 2012 by Joe *

**Calculus**

A large tank is filled with 200 gallons of pure water. Brine containing 1 pound of salt per gallon is pumped into the tank at the rate of 5 gallon per minute. The well-mixed solution is pumped out at the same rate. (a) Find the number A(t) of pounds of salt in the tank at any ...
*November 23, 2009 by Thomas*

**chemistry**

in HNO3 titration, you add few drops of phenolphthalein indicator to 50.0 mL of acid in a flask. you quickly add 20.00 mL of 0.0547 M NaOH but overshoot the end point, and the solutions turn deep pink. instead of starting over, you add 30.00 mL of acid, and the solution turns ...
*September 27, 2014 by shane*

**Chemistry**

A student mixes four reagents together, thinking that the solutions will neutralize each other. The solutions mixed together are 50.0 mL of 0.100 M hydrochloric acid, 100.0 mL of 0.200 M of nintric acid,500. mL of 0.0100 M calcium hydroxide, and 200.0 mL of 0.100 M rubidium ...
*October 7, 2014 by melbell*

**chemistry need help plzzz tomorrow is a TEST!!!**

phosphoric acid is the active ingredient in many commercial rust-removing solution.calculate the volume of concentrated phosphoric acid (14.6 mol/L)that must be diluted to prepare 500mL of a 1.25 mol/L solution. how can i calulate the volume cocentration for this question.... ...
*December 9, 2010 by TARA*

**gr.7 math**

each expression has four 4s and equals 1. 4+4/4-4 (4+4) / (4+4) 44/44 a. Evalute the xpressions to show that they all have a value of 1. b. Make new expressions that equal each whole number from 2 to 10 for example, 4/4+4/4=2 -you may combine digits. -you can multiply, divide...
*September 22, 2009 by vanny :)*

**math**

each expression has four 4s and equals 1. 4+4/4-4 (4+4) / (4+4) 44/44 a. Evalute the xpressions to show that they all have a value of 1. b. Make new expressions that equal each whole number from 2 to 10 for example, 4/4+4/4=2 -you may combine digits. -you can multiply, divide...
*September 22, 2009 by marry*

**math**

each expression has four 4s and equals 1. 4+4/4-4 (4+4) / (4+4) 44/44 a. Evalute the xpressions to show that they all have a value of 1. b. Make new expressions that equal each whole number from 2 to 10 for example, 4/4+4/4=2 -you may combine digits. -you can multiply, divide...
*September 22, 2009 by ashely*

**MATH**

each expression has four 4s and equals 1. 4+4/4-4 (4+4) / (4+4) 44/44 a. Evalute the xpressions to show that they all have a value of 1. b. Make new expressions that equal each whole number from 2 to 10 for example, 4/4+4/4=2 -you may combine digits. -you can multiply, divide...
*September 22, 2009 by NEED HELP IN MATH PLEASE!*

**P. Chemistry **

Can anyone direct me on how to solve this problem? All of the variables are makin my head spin--not sure how to organize them. If you can give equations to use that would help.Thnx! 1 L of an impure water solution has a freezing point of -11 °C. Which of the following is the ...
*March 7, 2010 by Tommy*

**AP Chemistry**

How can you find the average temperature of a refrigerator or any fridge by using colligative properties?? I am doing a lab in school and i'm not sure how to approach or start this. I know that you have to have two solutions where on one solution, you put a tremendous amount ...
*December 30, 2012 by Sarah*

**Chemistry**

I am stuck in this problem I need to calculate the molality first so I could find T but I don't know which one is the solvent and which one is the solution the problem is to calculate the freezing point of a solution containing 12.2g of benzoic acid, dissolved in 250g of ...
*October 27, 2008 by Maria*

**Chemistry**

A solution household bleach contains 5.25% NaClO, by mass. Assuming that the density of bleach is the same as water(1.0g/ml). Calculate the volume in mL of household bleach that should be diluted with water to make 500.0 ml of a pH= 9.80 solution. Here's what I've done so far...
*April 20, 2012 by Katherine*

**physics**

A hypodermic syringe is attached to a needle that has an internal radius of 0.303 mm and a length of 3.02 cm. The needle is filled with a solution of viscosity 2.00 10-3 Pa · s; it is injected into a vein at a gauge pressure of 16.1 mm Hg. Ignore the extra pressure required to...
*March 22, 2013 by ray*

**chemistry**

Given a solution in moles per litre how would you convert to parts per million)ppm.) could you help,no other information given apart from solution contains a known concentation of aluminium mols/L. Convert mols to grams. That will be grams per 1000 mL. Convert that to mg/L. ...
*August 9, 2007 by walter*

**chemistry**

Assuming the density of a 5% acetic acid solution is 1g/ml, determine the volume of the acetic acid solution necessary to neutralize 25ml of 0.1m naoh also record this calculation on your report My calculation 1g/ml x 1000ml x 0.05/61 = 0.81M 0.81m = 25ml x 0.1 0.81m = 2.5 x= ...
*September 9, 2012 by Fai*

**chemistry**

sorry to keep bugging you, but if it makes you feel better i am understanding it more. what if you have the same numbers, but you are trying to find the concentration of an UNKNOWN acid. all you have is: Volume of Unknown Acid Volume of Stock Solution Concentration of Stock ...
*October 31, 2008 by Vanessa*

**Math**

A state university wants to increase its retention rate of 4% for graduating students from the previous year. After implementing several new programs during the last two years, the university reevaluated its retention rate. Identify the Type I error in this context. A) The ...
*December 5, 2009 by Jennifer*

**Chemistry**

25 mL of a 0.10 M solution of the weak acid hydrofluoric acid, HF, (Ka = 7.2 x 10-4) is titrated with a 0.10 M solution of the weak base ammonia, NH3 (Kb = 1.8 x 10-5). Will the pH at the equivalence point be less than 7, equal to 7, or greater than 7? Explain. I’m guessing it...
*February 4, 2009 by Larry*

**math,correction**

can someone correct this for me. Directions: Solve the following systems by using either addition or substitution. If a unique solution does not exist, state whether the system is dependent or inconsistent. 10x + 2y = 7 y = -5x + 3 the answer: The variable disappeared and 6 ...
*February 5, 2007 by jasmine20*

**Chem!!!!!!**

5. Concentration of 0.24L KMnO4 solution required to oxidize 2.7g of Oxalic Acid??? 5H2C2O4 (aq) + 6H+ + 2MnO4- (aq) --> 10CO2 (g) + 2 Mn2+(aq) +8H20 (l) 4.How many grams of calcium chloride can be prepared if a student uses 500g if calcium carbonate and 2.00L of a 4.00 Mol...
*June 5, 2009 by Alex*

**Error ! question**

If the company administers n=10 identical triangle taste tests to this job applicant and if we say that ‘x’ is the number of correct identifications made (in n=10 trials), then the Rejection Region is the “set of values which ‘x’ could assume that will lead us to reject the ...
*December 2, 2009 by Desire*

**math**

Determind the nature of the solutions of the equation x^2+4=0 Choose the nature of the solutions of the equation. A) 2 imaginary solution b) 1 real solution c) 2 real solutions Thank you for your help.
*August 1, 2009 by Kay*

**chemistry**

An ice-bath made with sodium chloride will be 9 ± 1 oC when the solution is about 23% sodium chloride by mass. The density of solid sodium chloride is about 2 g/cm3. What volume of solid NaCl would you add to 200 g water to make a 23% NaCl solution? ANY HELP WOULD BE AWESOME!...
*February 13, 2014 by Jamie*

**Maybe you know this one..**

Heyy, I posted this before but it kinda got pushed down and ignored, and I was hoping maybe DrBob might have an idea since no one else did! okay I have this question about chemistry and its driving me nuts. It feels like I am so close but am just missing something. The ...
*February 3, 2007 by Tracy*

**chemistry**

What is the vapor pressure at 23 ¢ªC of a solution of 1.20 g of naphthalene, C10H8, in 25.6 g of benzene, C6H6? The vapor pressure of pure benzene at 23 ¢ªC is 86.0 mmHg; the vapor pressure of naphthalene can be neglected. Calculate the vapor pressure lowering of the solution.
*April 15, 2013 by george*

**Chemistry**

a volume of 50mL of a standard HCl solution is needed to neutralize 50 mL of 1x10-2 M NaOH. what volume of this HCl solution is needed to neutralize 50 mL of 1x10-2 M Ba(OH)2
*May 3, 2010 by Bianca*

**chemistry**

Question: When a pink aqueous solution of potassium permanganate, faintly acidified with dilute sulfuric acid was treated with 10% aq. hydrogen peroxide, the reaction took place with the evolution of gas bubbles, and the pink solution was turned colorless. Further chemical ...
*May 5, 2011 by Shadow*

**Pre-calculus-check answers**

Describe the linear programming situation for this system of inequalities where you are asked to find the maximum value of f(x,y)=x+y. Answer: an optimal solution 2)Describe the linear programming situation for this system of inequalities: Answer: an optomal solution
*August 23, 2008 by Lucy*

**Pre-Calculus-check answers**

Describe the linear programming situation for this system of inequalities where you are asked to find the maximum value of f(x,y)=x+y. Answer: an optimal solution 2)Describe the linear programming situation for this system of inequalities: Answer: an optomal solution
*August 30, 2008 by Lucy*

**Pre-Calculus check answers**

Describe the linear programming situation for this system of inequalities where you are asked to find the maximum value of f(x,y)=x+y. Answer: an optimal solution 2)Describe the linear programming situation for this system of inequalities: Answer: an optomal solution
*August 31, 2008 by Lucy*

**Chemistry**

If a buffer solution is 0.190 M in a weak acid (Ka = 5.8 x 10^-5) and 0.550 M in its conjugate base, what is the pH? What if it said "if a buffer solution is ___ M in a weak base (Kb = ____) and ___ M in its conjugate acid, what is the pH? Would the steps from the first ...
*April 22, 2012 by Katherine*

**Chemistry**

A solution of iodine (I2) in carbon tetra-chloride(CCl4) is used when iodine is needed for certain chemical tests. how much iodine must be added to prepare a 0.480 m solution of iodine in CCl4 if 100.0g of carbon tetra-chloride is used?
*June 15, 2012 by punk480*

**College Chemistry**

The Question Is: "A student weighs 0.347 g of KHP on a laboratory balance. The KHP was titrated with NaOH and the concentration of the NaOH determined to be 0.110 M. For the second titration, the student correctly diluted 6 M HCl from the reagent shelf using a graduated ...
*October 19, 2010 by James*

**AP CHEM**

I'm currently working on a lab in which I have to make the solution boil at 245 degrees F. The solution will be a mix of ethylene glycol and I have to caluculate the volumes of water and solute needed to make the solution. here's my work so far. X= mL C2H4(OH)2 175mL-X=mL H20 ...
*February 10, 2008 by Jonathan*

**math**

WageWeb is a service of HRPDI and provides compensation information on more than 170 benchmark positions in human resources. The October 2003 posting indicated that labor relation managers earn a mean annual salary of $88,000. Assume that annual salaries are normally ...
*June 20, 2013 by TOM7*

**Chemistry- test for presence of sulphate**

I have a solution of Fe2(SO4)3, i.e. iron(III) sulphate solution. To test for the presence of the sulphate anion, nitric acid & barium nitrate were added. A white precipitate was obtained. Please help to check if the following equation is correct for the above reaction? Fe2(...
*January 18, 2009 by june*

**Chemistry**

A reaction is said to be diffusion controlled when it occurs as fast as the reactants diffuse through the solution. The following is an example of a diffusion controlled reaction. The rate constant for this reaction is 1.4x1011 M-1s-1 at 25oC and the reaction obeys the ...
*May 19, 2009 by Kevin*

**chemistry**

a patient receives 250 mL of a 4.0% (m/v) amino acid solution twice a day. a) how many grams of amino acids are in 250mL of solution? b) how many grams of amino acids does the patient receive in one day? For a) I came up w/10g and for b) I came up w/ 20g in 1 day. Is this ...
*May 4, 2011 by Connie*

**chemistry**

Benzoic acid and quinine are dissolved in a solution of dichloromethane. Besides the normal neutral forms for benzoic acid and quinine, will there be any other chemical form(s) present in the dichloromethane solution? (benzoic acid pKa = 4.2; quinine pKa = 8.5)
*August 22, 2010 by Kay*

**Chemistry (urgent)**

Hydrolysis of a compound A, C7H6cl2 was carried out by refluxing with excess potassium hydroxide solution. the resulting solution was acidified with dilute HNO3 acid and excess silver nitrate was added to precipitate the chloride ions as silver chloride. 0.718g of silver ...
*October 23, 2014 by Kris*

**chemistry**

The vapor pressure of pure water at 70°C is 231 mm Hg. What is the vapor pressure depression of a solution of 115 g of the antifreeze ethylene glycol, C2H6O2, a nonvolatile compound, in 205 g of water? Use molar masses with at least as many significant figures as the data ...
*December 12, 2012 by Brad*

**chem**

a 2.50g sample of hydrate of calcium sulfate losses 0.523g of water when heated. what is the mass percent of water in the hydrate and the formula for the hydrate difference of the two masses divided by the initial mass. I believe Adam should reconsider his answer. mass percent...
*June 19, 2007 by mocha81*

**math**

can someone check and see if i did this right An 800 g solution of acid and water contains 128 g of acid. What percent of the solution is acid? 100=128/800*100 128/800=6.25 6.25*100=625
*January 31, 2008 by jj*

**algebra 2**

i forget what the n in the factorial theorem (n/r-1) is. Does anyone know? In statistics, "n" typically stands for the number of scores in a sample. I hope this helps. Thanks for asking.
*May 1, 2007 by Bob*

**English**

i need a sample lesson plan for what makes us grow with 15 childrens objectives, material,learning activites
*October 7, 2007 by Anna*

**Career**

How do i create a creative Portfolio Cover Page. what should be on it? where can i find one already comlete a sample?
*November 20, 2007 by Bryan*

**government**

a candidate's victory in an election is sometimes interpreted by him or her as a. a representative sample b. a medium c. a sound bite d. a mandate a
*December 28, 2007 by jere*

**government**

a candidate's victory in an election is sometimes interpreted by him or her as a. a representative sample b. a medium c. a sound bite d. a mandate a
*December 28, 2007 by jere*

**Chemistry**

Which sample contains particles in a rigid, fixed, geometric pattern? a. CO2 b. HCl c. KCl d. H2O
*March 5, 2008 by John*

**chemistry**

Using a BCA table, calculate the molarity of a 25.0 mL sample of HNO3 thats is titrated to its endpoint with 22.7 mL of 0.200 M NaOH.
*May 11, 2008 by caleb*

**chemistry**

What approach do you suggest using to prevent your water sample from cooling off before you start your measurements?
*October 23, 2008 by Lilit****

**DDP...help**

if the accepteable range is between .745 in and .755 in, what percentage of your sample blocks would be considered unaccesptable?
*November 8, 2008 by Anonymous*

**Biochemistry**

For dialysis, why is leaving it overnight a more adopted practise than measuring the sample during the lab period?
*February 6, 2009 by Chris*

**Chemistry**

Calculate the molar concentration of acetic acid (CH3COOH) in a 5.00-mL sample of vinegar (density is 1.00 g/mL) if it is titrated with 25.00 mL of NaOH.
*March 4, 2009 by Jake*

**college**

Request for sample letters containing bad news messages. Need a few realy quick
*March 24, 2009 by Jason*

**IT**

I need to create a sample plan on remodeling a bathroom this is for class IT 221N Analysis and Design Information Systems
*May 19, 2009 by Becky*

**Chemistry**

Is the following statement true? Explain fully. "Any sample made up of only one substance is homogeneous."
*September 9, 2009 by George*

**Statistics**

A random sample of 50 students has a test score average with a standard deviation of 10.9. Find the margin of error if c = 0.90.
*November 28, 2009 by Jessica*

**Chemistry**

As a sample of the radioactive isotope 131 I decays, its half-life a)decreases b)increases c)remains the same
*May 5, 2010 by Danny*

**environmental science**

Should humans strive to preserve a representative sample of all biomes or aquatic zones
*May 13, 2010 by Anonymous*

**Chemistry**

If radon-222 has a half-life of 3.8 days, determine how long it takes for only 1/8 of a sample to remain.
*June 1, 2010 by Joe*

**statistics**

There are 120 possible samples of size n=3 which can be drawn from this population of 10 scores: 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 Write each sample and calculate its mean
*June 15, 2010 by Joe*

**CHEM**

A 60.0 sample of water is heated to its boiling point. How much heat (in ) is required to vaporize it? (Assume a density of 1.00 .)
*September 2, 2010 by Anonymous*

**expository essays**

i do not know how to do the above. Can you walk me throw it? Or where can I finda a sample paper and follow it with my own essay title?
*September 9, 2010 by diane*

**Chemistry**

A sample of gas occupies 3.00 L at 760 torr. Calculate the volume it will occupy at 1.45 atm and the same temperature?
*September 23, 2010 by Lisa*

**math**

Assume that your sample space is S = {O1, O2, O3, O4, O5, O6 } with associated weights (probabilities) w1 = 0.15, w2 = 0.25, w3 = 0.10, w4 = 0.20, w5 = 0.15, and w6 = 0.15. Determine the probability of the following events: {O3 }∩{O5 }:
*September 29, 2010 by Tiff*

**statistics**

Assume that your sample space is S = {O1, O2, O3, O4, O5, O6 } with associated weights (probabilities) w1 = 0.15, w2 = 0.25, w3 = 0.10, w4 = 0.20, w5 = 0.15, and w6 = 0.15. Determine the probability of the following events: {O3 }∩{O5 }:
*September 29, 2010 by Tiff*

**Chem**

A 50 ml sample of 0.025M AgNo3 is mixed with 15 ml of 0.04 M CrCl3. How many grams of AgCl will precipitate? Please show steps
*October 9, 2010 by MAX*

**General Chemistry**

How much heat is absorbed by a 25.0-g sample of gold at 25.0 degrees celcius when it is immersed in boiling water?
*October 15, 2010 by Saw*

**College Chem**

How many calories of energy are needed to vaporize a 20.2 g sample of liquid ethanol at its normal boiling point of 78 oC?
*October 24, 2010 by Sam*

**Chemistry**

what would an open manometer look like in which the pressure of the gas sample is 34.5 kPa higher than the atmosphere?
*January 6, 2011 by al*

**Chemistry 125**

What is the maximum mass of water that can be released by heating a 6.895 g sample of nickel(II) sulfate heptahydrate?
*February 10, 2011 by Andrew *

**math**

For a sample of n = 20 individuals, how large a Pearson correlation is necessary to be statistically significant for a two-tailed test with a = .05?
*November 2, 2012 by meka*

**statistics**

A 99% confidence interval for population variance is being formulated based on a sample of 16 observations. What are appropriate values for X^2
*March 13, 2011 by Sandy*

**Chemistry**

A sample of a gas weighs 4.526g and has a volume of 890.0 mL at 645.0 torr and 29(degrees C). What is its molar mass?
*March 31, 2011 by Toni Jones*

**Chemistry**

why the acidic medium is used for determination of the amount if iorn in a sample of soil using standard KMnO4
*April 4, 2011 by DILANI*

**chem**

what is the total mass of rn-222 remaining in an original 160g sample after 19.1 days? 1 2.5g 2 5.0 g 3 10g 4 20g how do you do this ?
*May 16, 2011 by John *

**Chemistry**

A few drops of AgNO3 is added to a sample of the unknown. A white precipitate appears. Which ion is present?
*June 6, 2011 by Adam*

**chemistry**

A sample of oxygen occupies 38.9L at STP. What will the pressure need to be in Torr. if the volume is to be changed to 32.2L without a change in T.
*June 9, 2011 by kathleen*

**Math**

How long will it take for a 1 g sample of Polonium 210 to lose all but 1/28 of its radioactivity if the half-life is 140 d?
*August 1, 2011 by Kate*

**Math**

How long will it take for a 1 g sample of Polonium 210 to lose all but 1/28 of its radioactivity if the half-life is 140 d?
*August 1, 2011 by Kate*

**Science economic**

Cesium 138 has a half life equal to 32.2 minutes. how long will it take for 2/4 of this sample to decay
*September 5, 2011 by christine*

**Chemistry**

Given that a sample of air is made up of nitrogen, oxygen, and argon in the mole fractions 78% N2, 21% O2, and 1.0% Ar, what is the density at stp?
*September 11, 2011 by Anonymous*

**buss/stats**

what is it called when all the items in the population have the same chance of being selected for the sample?
*October 8, 2011 by Tim*

**Chemistry**

How many grams of a 250- g sample of thorium - 234 would remain after 40 days had passed?
*October 23, 2011 by Divine*

**chemistry**

calculate the quantity of heat (J) which flows froma 125g sample of magnesium as it cools from 650K to 300K
*November 3, 2011 by payton*

**statistics**

The following is a sample of 19 Novemeber utilily bills(in dollars) from a neighorhood: 52,62,66,68,72,74,74,76,76,76,78,78,82,84,84,86,88,92,96. Find the five-number summary.
*March 7, 2012 by Rose*

**calculus**

a radiotactive isotope lose 1/5 of its atoms in a sample decay after 14 years. find the half life.
*April 12, 2012 by Mackenzie*

**critical thinking**

a topic of interest to you and explain how you would come up with a reliable sample for obtaining peoples' opinions.
*May 26, 2012 by rb*

**Chemistry Science**

. When a 28.7 g sample of KI dissolves in 60.0 g of water in a calorimeter, the temperature drops from 27.2oC to 13.2 oC . Calculate ΔH for the process.
*May 29, 2012 by science girl*

**statistics**

how large a sample size is needed for 2 sided 95% confidence interval to have a length of 2 weeks when mean is 3.6
*June 28, 2012 by jo*

**Chemistry 1046**

If a sample of Sr-90 initially contains 1.1 mmol of Sr-90, how many millimoles are left after 25.20 years? any ideas on where to start??
*July 3, 2012 by Anonymous*

**statistics 251**

how do i find the standard deviation and sample variance for $7448, $4911, $9051, $6374, $4227
*September 13, 2012 by amirah*

**statistic**

in a random sample of 400 voter, 120 plan to vote for candidate A. determine a 95% confidence interval
*November 1, 2012 by John*

**chemistry**

A 93L sample of dry air is cooled from 145 to-22 under constant pressure.What is the final volume?
*November 25, 2012 by nikki*

**biostatistic**

can we use t-test for two independent sample and dichotomus study with less than five success or failures?
*November 28, 2012 by nono*

**stats**

if i have a sample size of 200, 16% are poor, what is my mean and standard deviation. my answers do not make any sense
*January 1, 2013 by gary*

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