Friday

August 26, 2016
Number of results: 30,724

**maths**

(a)(i)use the composite rule to differentiate the function f(x)=(x^2-6x+23)^(3/2). (ii)use the composite rule and your answer to part (a)(i) to show that the function g(x)=(x-2)/(x^2-6x+23)^(3/2) has derivative g'(x)=(5+9x-2x^2)/(x^2-6x+23)^(5/2). (iii)find any staionary ...
*May 20, 2011 by alan*

**Statistics (45)**

In developing patient appointment schedules, a medical center wants to estimate the mean time that a staff member spends with each patient. How large a sample should be taken if the desired margin of error is two minutes at a 95% level of confidence? How large a sample should ...
*May 6, 2014 by Mia*

**chemistry**

Expressing concentration in units of μg/mL or mg/mL are common in biochemistry, where accurate molecular weights of biomolecules are not always known. The plot below is the standard curve of a Bradford assay, a colorimetric method used to determine the concentration of ...
*September 17, 2013 by Libbie*

**Chemistry**

In a titration for the determination of the chloride ion, a solution of 0.1M agno3 is used against a solution, the volume of which is 100ml. At the completion of the titration, the residual concentrations of silver and chloride ions are equal and the total volume is now 125ml...
*October 22, 2014 by Michelle *

**chemistry**

he Fe(ox)33– complex ion creates an emerald green solution when dissolved. The observed solution color of the complex indicates the size of o is: A. large. B. small. C. in between. D. inconclusive, more information is needed. The observed solution color of the complex ...
*June 30, 2010 by ....*

**science**

i need help with a packet that im struggling with my questions are write the total number of atoms present for the following questions: a. 4SO2 now i tried and got 8O'S and 1S b. 8O2 i tried and got 16 all together c. 3Al2(SO4)3 i tried and got 6Al, 3S, and 12O my next ...
*January 12, 2015 by maddy*

**Chemistry II**

Acetone, C3H6O, is the main ingredient of nail polish remover. A solution is made up by adding 35.0mL of acetone(d=0.790g/mL) to 50.0mL of ethyl alcohol,C2H6O(d=0.798 g/mL). Assume that the volumes are additive. From this information calculate the molarity of acetone in the ...
*September 27, 2009 by Mandy*

**Chemistry**

Which of the following pairs would make a good buffer solution in an aqueous solution? A) H2SO4 and NaHSO4 B) Ca(NO3)2 and HNO3 C) HCl and NaCl D) HF and NaOH E) none of them I know the answer is D but I don't understand why. I would think it would be C since a goo buffer is a...
*March 20, 2013 by Jonah*

**chemistry**

What is the pH of a buffer solution that is made by adding 21.0 grams of sodium fluoride to 1.00 Liter of 0.15M hydrofluoric acid? (see the Table above for the Ka of hydrofluoric acid; calculate the pH to 2 decimal places) hint: you will have to find the molarity of NaF in ...
*June 16, 2013 by dennis*

**chemistry**

What is the pH of a buffer solution that is made by adding 21.0 grams of sodium fluoride to 1.00 Liter of 0.15M hydrofluoric acid? (see the Table above for the Ka of hydrofluoric acid; calculate the pH to 2 decimal places) hint: you will have to find the molarity of NaF in ...
*June 16, 2013 by Dennis*

**Chemistry**

What is the pH of a buffer solution that is made by adding 21.0 grams of sodium fluoride to 1.00 Liter of 0.15M hydrofluoric acid? (see the Table above for the Ka of hydrofluoric acid; calculate the pH to 2 decimal places) hint: you will have to find the molarity of NaF in ...
*June 17, 2013 by D.J.*

**Anyone please help(math)**

Which number is a solution of the inequality? g>6.4 a. 7 b. 6 c. 6.4 d. -7 Which number is a solution of the inequality? g+3>6 a. 3 b. 4 c. -3 d. -4 Which number is a solution of the inequality? 12<y(8-y) a. 0 b. 1 c. 2 d. 3
*January 9, 2014 by Ashley mccgarvey*

**Math**

Let x be a random variable representing the monthly cost of joining a gym. We may assume that x has a normal distribution and that the population standard deviation is $5.20. A fitness magazine advertises that the mean monthly cost of joining a gym is $35. You work for a ...
*December 22, 2012 by Alison*

**Chemistry**

Titration was used to determine the molarity of acetic acid in vinegar. A primary standard solution of KHP was used to standardize the NaOH. 1. When performing this experiment, impure KHP was used to standardize the NaOH solution. If the impurity is neither acidic or basic, ...
*March 28, 2014 by Sandy*

**math help pls pls**

Maya had $27. She spent all the money on buying 3 burgers for $x each and 2 sandwiches for $y each. If Maya had bought 2 burgers and 1 sandwich, she would have been left with $11. A student concluded that the price of each burger is $5 and the price of each sandwich is $6. ...
*December 21, 2015 by Oscar*

**chemistry help!!! (clueless)**

1. Consider the conductance meter and the titration method of determining the salt content of a brine sample. Discuss at least two advantages and two disadvantages of each method. 2. A corrosion technologist pipetted a 50.00 mL sample of an unknown brine and titrated it with ...
*June 19, 2006 by lightning*

**Math**

The owner of a large company is conducting a survey about job satisfaction, including questions about salary, hours, stress, and other conditions. There are about 800 employees in the company, including 100 executive positions, 650 middle-management positions, and 50 custodial...
*August 7, 2012 by Fatima*

**chem??????????????????**

YEs, it is the correct balanced equation bobpursley A 2.80 mol/L solution of iron (II) dichromate is combined with 5.00L of a 2.25 mol/L acidic solution of tin (II) bromide. Calculate the volume of iron (II) dichromate required. FeCr2O7 + SnBr2 --> SnCr2O7 + FeBr2 Is this ...
*May 16, 2007 by bobpursley*

**Algebra **

A dehydrated patient needs a 3.82% saline IV. Unfortunately, the hospital only has bags of 4% and 3% saline solutions. How many liters of each of these solutions should be mixed together to yield 5 liters of the desired concentration? So far I've come up with this: x= 4% ...
*October 11, 2010 by JerryJ*

**CHEMISTRY**

Lysozmyne is an enzyme that breks bacterial cell walls. A solution containing 0.150g of this enzyme in 210ml of solution has an osmotic pressure of 0.217kPa at 25*C. What is the molar mass of Lysozmyne? I cant find the chemical formula anywhere. I have used the osmotice ...
*October 15, 2010 by lulu78*

**Chemistry**

Suppose you tired to carry out a double-replacement reaction by mixing together equal volumes of a solution that contained dissolved NaF and a solution that contained dissolved NaCl. Would you expect a reaction, if so write the balanced chemical equation?
*April 25, 2011 by Anonymous*

**chemistry**

2Na3PO4(aq)+3 Ba(NO3)2(aq)---->Ba3(PO4)2(s)+6NaNO3(aq) a solution containing 3.50g of Na3PO4 is mixed with a solution containing 6.40g of Ba(NO3)2 how many grams of product can be formed? and if the above reaction resulted in 3.659 g of white powder, what is the percent ...
*November 17, 2011 by mckayla*

**Chemistry**

1 g of acid was mixed with 120 ml of distilled water and the solution was filtered into a clean dry beaker. A 25 ml aliquot of this solution was titrated with 0.1120 M NaOH. The pH of the acid was recorded to be 4.42. Calculate the initial concentration of the weak acid and ...
*March 25, 2013 by Annie*

**Chemistry**

How do you calculate the standard enthalpy change for the reaction of an aqueous solution of barium hydroxide, Ba(OH)2, with an aqueous solution of ammonium nitrate, NH4NO3, at 25 degrees C? The complete ionic equation is: Ba2+(aq) + 2OH-(aq) + 2NH4+(aq) + 2NO3-(aq) ---> ...
*April 2, 2013 by Lisa*

**Organic-Chem Lab Question Need Help!!!**

a) Would 2-propanol be a suitable solvent to extract caffeine from an aqueous tea solution? Explain? b) You want to use 45 ml total of your extraction solution. Is it better to use three extractions of 15 ml each or one extraction of 45 ml? Explain your answer? Thanks!
*September 13, 2014 by Layla*

**Chemistry**

Suppose you tired to carry out a double-replacement reaction by mixing together equal volumes of a solution that contained dissolved NaF and a solution that contained dissolved NaCl. Would you expect a reaction, if so write the balanced chemical equation?
*January 29, 2015 by Keely*

**Chemistry Help**

How many milliliters of 0.534 M Ba(OH)2 solution are needed to completely neutralize 34.5 mL of 0.220 M HBr solution? The reaction is Ba(OH)2(aq) + 2HBr(aq) → BaBr2(aq) + 2H2O(l) I did 0.0345 * 0.220 = 0.00759 Moles of HCl =2*0.00759= 0.01518 0.01518*1000= 15.18 mL ...
*February 27, 2015 by Matthew*

**Chemistry**

I have water pH 7.0 insulation with various other things that do not affect pH, I am trying to add X amount of HCL to lower the solution to a pH of 1.5 I know pH=-log[HCl] but I'm not sure how to approach this problem, after this I am then trying to add NaOH to return the ...
*April 24, 2015 by Margaret*

**statistics**

Workers in several industries were surveyed to determine the proportion of workers who feel their industry is understaffed. In the government sector, 37% of the respondents said they were understaffed, in the health care sector 33% said they were understaffed, and in the ...
*October 20, 2014 by tia*

**Chemistry**

In a constant-pressure calorimeter, 50.0 mL of 0.300 M Ba(OH)2 was added to 50.0 mL of 0.600 M HCl. The reaction caused the temperature of the solution to rise from 23.77 °C to 27.86 °C. If the solution has the same density and specific heat as water (1.00 g/mL and 4.184 J/g·K...
*April 11, 2016 by Paul83*

**chemistry**

At equilibrium, a solution of formic acid at 25°C has a pH of 2.18. The pKa of formic acid, HCOOH, is 3.74. Which of the following is the initial concentration of the solution? Not sure what to do my thoughts: use henderson hasselback equation pH = pKa + log [conj base/acid] ...
*June 8, 2016 by James*

**Algebra Multiple choice!!! Help**

1.) Find the values of a, b, and c that will make the statement true. [5 a -2] [5 102] [3 4 –b] = [-3 -4 3] [2c 5 9] [-2 5 9] a.) 8R1-R2--> =R2 b.) -8R1-R2 -> =R2 c.) –8R1 +R2 -> =R2 d.) 8R1-R2 -> =R2 2.) Solve the system by triangularizing the augmented matrix and...
*March 28, 2013 by Kris*

**Chemistry**

I just need this checked over. I am not sure about the last part D. Temp c KBr 20 65 40 80 60 90 80 100 100 110 At 100 C, 10.5 g KBr/10gH2O = 105 g/100 g (just multiply the top and the bottom by 10 to give you 100 g H2O) B) Since the solubility at 100C is actually 110, no, it ...
*May 19, 2011 by Monster*

**Statistics**

The standard deviation of GPAs (grade point averages) of all male students at a college is .35 and the standard deviation of GPAs of all female students at the same college is .34. Suppose we take one sample of 40 male students and another sample of 50 female students from ...
*October 22, 2010 by Lisa*

**Statstics**

Let x be a random variable representing dividend yield of Australian bank stocks. We may assume that x has a normal distribution with \alpha =2.3% A random sample of 18 Australian bank stocks has a sample mean of x bar = 6.1%. For the entire Australian stock market, the mean ...
*August 7, 2011 by Justina*

**Physics**

If a supersaturated sugar solution is allowed to evaporate slowly, sugar crystals form in the container. Hence, sugar molecules go from a disordered form (in solution) to a highly ordered, crystalline form. Does this process violate the second law of thermodynamics? Explain.
*November 25, 2012 by S*

**Math**

1. –9p – 17 = 10 (1 point) –3 16 18 –16 2. w over four – 4 = 3 (1 point) –4 28 3 11 3. d over three+ 10 = 7 (1 point) 51 20 0 –9 4. –2(m – 30) = –6m (1 point) –15 –13 –8 8 5. 3n + 2= 8 + 2n (1 point) 3 4 5 6 Simplify the expression. 6. –6 – 7(c + 10) (1 point) 64 – 7c –76 – 7c...
*January 18, 2013 by plz help*

**chemistry**

PLEASE NOTE: Titration requires several steps in order to obtain exact results. The procedures described in this lab assume that you have already done the TITRATION TUTORIAL and are familiar with the technique. 1. Prepare the NaOH solution by dissolving approximately 4g of ...
*April 15, 2011 by Zach*

**Chemistry**

An aqueous solution contains 2.0 % NaCl by mass. (1) Calculate the molality (NOT molarity!) of the solution. (2) Calculate the mole fraction of the solution. I know how to solve both but the problem is missing one other compound/element. I know that molality is moles per kg of...
*January 26, 2010 by .*

**Chemistry please help**

Elemental mercury was first discovered when a mercury oxide was decomposed with heat, forming mercury metal and oxygen gas. When a 0.204-g sample of the mercury oxide is heated, 0.189 g of mercury metal remains. a)what is mole ratio of mercury to oxygen in the sample? would it...
*February 15, 2012 by Adam*

**chemistry**

A buffer is made by adding 0.300 mol HC2H3O2 and 0.300 mol NaC2H3O2 to enough water to make 1.00 L of solution. The pH of the buffer is 4.74 . Calculate the pH of this solution after 0.020 mol of NaOH is added.
*December 10, 2009 by Ericka*

**chemistry**

A solution is 2.0×10−2M in both chromate and sulfate anions and . To this solution, 0.55M Pb(NO)3 is slowly added. What is [Pb2+] at the point at which the second anion begins to precipitate (in M)? The second anion being the, sulfate anion.
*April 14, 2011 by nahang*

**Chemistry**

When 5.00 g of NaOH(s) are added to 100 g of water using a calorimeter, the temperature rises from 25.0 to 37.5 °C. Calculate the molar heat of solution. NaOH(s)--->Na(aq)+OH(aq) Assume that the specific heat capacity of water is 4.18 J/gK and that of the NaOH(aq) solution ...
*November 14, 2012 by FIrst_lady*

**math help please**

Which cannot describe a system of linear equations? no solution exactly two solutions infinite solutions exactly one solution I thought it was A or D but someone else is telling me it is B...no I'm confused...I thought it was 2 or more solutions
*November 23, 2012 by Deborah*

**Chemistry **

Help! I have to get this done tonight and I cannot get this answer right. A solution of water (Kf=1.86 ∘C/m) and glucose freezes at − 3.55 ∘C. What is the molal concentration of glucose in this solution? Assume that the freezing point of pure water is 0.00 &#...
*February 28, 2016 by Emmalee*

**Order Pairs Math**

Which ordered pair is a solution of the equation y = x – 3? (–2, 5) (–5, 2) (2, 5) (5, 2) Which ordered pair is a solution of the equation y = 5x? (–2, 10) (–5, 25) (–3, 15) (–2, –10) Which ordered pair is a solution of the equation y = –7x + 2? (1, 2) (8, –54) (5, –35) (1, –7)
*September 13, 2013 by Jman*

**ALGEBRA-MAT117**

How do you know if a quadratic equation will have one, two, or no solutions? How do you find a quadratic equation if you are only given the solution? Is it possible to have different quadratic equations with the same solution?
*January 12, 2009 by Paradise*

**College Chemistry**

A 30.00 mL volume of a weak acid, HA, (Ka = 3.8 x 10^-6) is titrated with 39.00 mL of 0.0958 M NaOH to the equivalence point. A.) What is the pH of the acid solution, before any base is added to it? B.) What is the pH of the acid solution after exactly 19.50 mL of NaOH is added?
*April 13, 2010 by Shell*

**chemistry**

a cell is constructed by immersing a strip of silver in .10 M AgNO3 solution and a strip of lead in 1.0 M Pb(NO3)2 solution. A wire and salt bridge complete the cell. What is the potential of the silver electrode in the cell?
*December 9, 2010 by audrey*

**science**

to prepare 500cm^3 of glucose solution of concerntration 1M. The chemical formula of glucose is C6H12O6.calculate (1)the relative molecular mass and molar mass.(2)the amount of glucose which will be in the solution.(3)the mass of glucose to be weighed
*July 1, 2012 by abajane*

**science**

to prepare 500cm^3 of glucose solution of concerntration 1M. The chemical formula of glucose is C6H12O6.calculate (1)the relative molecular mass and molar mass.(2)the amount of glucose which will be in the solution.(3)the mass of glucose to be weighed
*July 1, 2012 by abajane*

**Chemistry**

A solution is prepared by dissolving 0.1 mol of ethanoic acid (CH3COOH) in 500ml of water at 25 C. pKa of ethanoic acid is 4.7. What is the pH of the solution? I'm assuming the equation is pH = pKa + log[Base]/[Acid] but can't get it to work?
*October 21, 2015 by Becca*

**chemistry**

three student chemists measured 50.0 mL of 1.00 M NaOH in separate Styrofoam "coffee cup" calorimeters ( Part B). Brett added 50.0 mL of 1.10 M HCI to his solution of NaOH; Dale added 45.5 mL of 1.10 m HCL 9 eqaul moles) to his NaOH solution. Lyndsay added 50.0 mL of 1.00 m ...
*January 17, 2011 by Daniel*

**Chemistry**

Colligative Properties The freezing point of distilled water was determined by recording a thermogram: -0.176. The freezing point of a 0.200 m (molality) solution containing an unknown, ionic compound was determined by recording a second thermogram. a. Determine the freezing ...
*January 28, 2014 by Sam*

**chemistry**

I know everyone guessed i had a few more i couldnt do. Sorry but assistance please: 1.Sucralfate (molecular weight: 2087g/mol) is a major component of Carafate® which is prescribed for the treatment of gastrointestinal ulcers. The recommended dose for a duodenal ulcer is 1g ...
*November 17, 2015 by mikey*

**Chemistry**

A 2.50 L flask was used to collect a 5.65 g sample of propane gas, C3H8. After the sample was collected, the gas pressure was found to be 741 mmHg. What was the temperature of the propane in the flask. P= 741 mmHg(1 atm/760 mmHg)= .975 atm V= 2.50 L n= 5.65 g C3H8 (1 mol/44 g...
*October 23, 2007 by Lauren*

**Chemistry**

7.5 g of a solid are added to 87.6g of water at 23.7 degrees C. When the solid has all been dissolved and thoroughly mixed with the water, the temperature of the solution is decreased by 6.2 degrees C. Calculate the heat of the solution in joules per gram of the solid.
*July 15, 2008 by Anonymous*

**Math**

For problems 1 and 2, determine how many solutions there are for each triangle. You do not have to solve the triangle. 1. A = 29°, a = 13, c = 27 2. A = 100.1°, a = 20, b = 11 For problems 3-6, solve each triangle using the Law of Sines. If there is no solution, write “no ...
*January 13, 2011 by Tabitha*

**chemistry**

a portion (10.0 ml)of a solution containing the chloride anion was treated with silver nitrate to yield a precipitate (0.1713 g) of the silver chloride. calculate the molar concentration of the chloride anion in the solution. first write the equation.
*October 18, 2011 by TROUBLED*

**chemistry**

A solution is prepared by adding 30.00 g of lactose (milk sugar) to 110.0 g of water at 55 °C. The vapor pressure of pure water at 55 °C is 118.0 torr. The MW of lactose is 342.3 g/mol. What is the partial pressure of water above the solution?
*November 7, 2011 by Anonymous*

**chemistry**

The density of acetonitrile, CH3CN, is 0.786 g/mL, and the density of methanol, CH3OH, is 0.791 g/mL. A solution is made by dissolving 15.0 g of methanol in 250.0 mL of acetonitrile. Assuming that the volumes of the solute and solvent are additive, what is the molarity of ...
*February 5, 2015 by S*

**Chem 30 **

The solubility of KCL is water is 30g/100g of water at 20 degrees centigrade. A heated solution containing 60g of KCl in 140g of water is cooled to 20 degrees C. How many grams should precipitate out of solution?
*June 22, 2015 by Jim*

**Chemistry**

in this experiment you are you will begin by preparing a dilute soultion of sodium hydroxide by taking 50 ml of 3 M NaOh stock solution and diluting it with 250 ml of water. i found that and the answer was .5 but how do i do this b. calculate the number of moles and grams of ...
*February 23, 2010 by Chris*

**Chemistry**

A solution contains 0.0273 M HNO3, 0.0302 M HI, and 0.320 M formic acid, HCOOH. What is the pH? A solution contains 0.160 M Ba(OH)2 (strong base) and 0.360 M ammonia, NH3 (weak base). What is the pH? I'm really not sure how to do this. I tried and got .443 and 12.91 ...
*March 2, 2013 by Anonymous*

**Chemistry**

The following data was obtained from titrating a solution containing 25 mL of 0.0100 M MgCl2 solution, 1 mL of NH3OH buffer, and 10 drops of Calmagite with EDTA. Calculate the concentration of EDTA. Report the answer with three sig figs. Please help it only shows a graph with ...
*May 13, 2013 by shannon*

**biology **

You need a 5 microgram glucose/ml aqueous solution, but the lab balance is accurate to only 0.01g (ie., it displays 2 digits to the right of the decimal point) Describe 2 methods by which you could accurately prepare this solution using the lab balance. I don't know what to do...
*September 4, 2013 by alex*

**statistics**

The Sledge Tire and Rubber Company plans to warranty its new mountain bike tire for 12 months. However, before it does this, the company wants to be sure that the mean lifetime of the tires is at least 18 months under normal operations. It will put the warranty in place unless...
*March 12, 2012 by nouah*

**chemistry**

I know the formula is Ma x Mla / 1000 x Sa / Sb = Mb x Mlb / 1000 if 175 ml of KOH of unknown concentration with a methyl red indicator present is titrated with [0.275 M] H3PO4, the yellow solution turns red after 29.6 ml of the H3PO4 is added. What is the molarity of the KOH...
*September 4, 2008 by casey*

**Science**

Please check my answers (at the bottom) with these questions. 1. An apple quickly changes color when exposed to air. This demonstrates a ________. (1 point) physical property chemical property physical change all of the above 2. When a chunk of dry ice is at room temperature, ...
*May 7, 2013 by Annabelle Hartz*

**statistics**

A researcher wishes to estimate with 95% confidence the proportion of adults who have high speed internet access. Her estimate must be accurate within 4% of the true proportion. 1. Find the minimum sample size needed using a prior study that found that 48% of the respondents ...
*October 14, 2012 by Diana*

**Chemistry**

Prepare a theoretical titration curve for titration of 25.0 mL of 0.1037 formic acid (HCOOH; pKa = 3.75) solution (diluted to 100 mL volume with deionized water) by 0.0964 M solution of KOH. I have to determine volume of KOH needed to reach equivalence point, the pH of ...
*March 5, 2012 by Clint*

**Algebra**

How do you know if a quadratic equation will have one, two, or no solutions? How do you find a quadratic equation if you are only given the solution? Is it possible to have different quadratic equations with the same solution?
*September 30, 2008 by Laura*

**Algebra (please help!)**

Mary has a solution that is 60% alcohol and another that is 20% alcohol. How much of each should she use to make 100 milliliters of a solution that is 52% alcohol. I totally forget how to do this kind of problem. Please help if you can! Thank you so much! :)
*May 29, 2009 by Faith*

**ALGEBRA**

How do you know if a quadratic equation will have one, two, or no solutions? How do you find a quadratic equation if you are only given the solution? Is it possible to have different quadratic equations with the same solution?
*March 28, 2010 by GGIFT*

**Chemistry**

0.10 M solution of a weak monoprotic acid has a hydronium-ion concentration of 5.0 * 10^-4 M. What is the equilibrium constant, Ka, for this acid? a. 5.0 *10^-2 b. 5.0 * 10^-3 c. 2.5 * 10^-4 d. 2.5 * 10^-5 e. 2.5 * 10^-6 2. (Points: 1) What is the carbonate-ion, CO3^-2, ...
*May 13, 2010 by wite2khin*

**college Chemistry**

A 21.18 mL of 0.250 M NaOH is titrated with a H2SO4 solution. The initial volume of H2SO4 was 13.28 and the final volume of H2SO4 was 28.29 mL when the solution turned very slightly pink. What is the concentration of NaOH?
*December 6, 2010 by Ivy*

**Chemistry Help Pls!!!**

A 21.18 mL of 0.250 M NaOH is titrated with a H2SO4 solution. The initial volume of H2SO4 was 13.28 and the final volume of H2SO4 was 28.29 mL when the solution turned very slightly pink. What is the concentration of NaOH?
*December 6, 2010 by Jerome*

**college Chemistry**

A 21.18 mL of 0.250 M NaOH is titrated with a H2SO4 solution. The initial volume of H2SO4 was 13.28 and the final volume of H2SO4 was 28.29 mL when the solution turned very slightly pink. What is the concentration of NaOH?
*December 7, 2010 by Ivy*

**Precalculus **

Solve (log x)^2 = log x Also, when will their be a possibility that an equation will have an extraneous solution? Like if you got two solutions for a log equation, will a negative solution for x automatically be extraneous?
*November 20, 2012 by marcus *

**Chemistry**

A reference solution is to be prepared with 5 PPM parabenzopyrene (molecular weight = 252). The quantity of parabenzopyrene required for preparing one litre 5 PPM solution is (A) 252 mg (B) 25.2 mg (C) 5 mg (D) 252 g
*June 25, 2013 by rohit*

**math**

Weights of the vegetables in a field are normally distributed. From a sample Carl Cornfield determines the mean weight of a box of vegetables to be 180 oz. with a standard deviation of 8 oz. He wonders what percent of the vegetable boxes he has grouped for sale will have a ...
*April 9, 2014 by Anonymous*

**Econ 112**

A researcher believes that the average size of farms in the U.S. has increased from the 2002 mean of 471 acres. She took a sample of 23 farms in 2011 to test her belief and found a sample mean of 498.8 acres and a sample standard deviation of 46.9 acres. At a 5% levelof ...
*June 18, 2013 by Help*

**Statistics**

1. In developing patient appointment schedules, a medical center wants to estimate the mean time that a staff member spends with each patient. Using a value for the population standard deviation of eight minutes, determine: a. How large a sample should be taken if the desired ...
*October 27, 2008 by JYD*

**statistics**

Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5 stocks from the ...
*August 31, 2009 by Amy*

**Statistics**

Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5 stocks from the ...
*June 7, 2010 by Mary*

**QMB2100**

Chicken Delight claims that 90 percent of its orders are delivered within 10 minutes of the time the order is placed. A sample of 70 orders revealed that 60 were delivered within the promised time. At the .02 significance level, can we conclude that less than 90 percent of ...
*July 29, 2013 by Ariel*

**AP CHEM**

I have multiple... 1) If a metal ore contains 23.1% pure metal, how many pounds of pure metal can be obtained from 38 pounds of metal ore? Answer in units of pounds. 2) For the reaction 3 F2 + Cl2 → 2 ClF3 , what is the maximum amount of ClF3 (92.4482 g/mol) which could ...
*October 13, 2015 by Shannon*

**Chemistry**

A solution of household bleach contains 5.25% sodium hypochlorite, NaOCl, by mass. Assuming that the density of bleach is the same as water, calculate the volume of household bleach that should be diluted with water to make 500.0 mL of a pH = 10.23 solution.
*March 23, 2012 by Jematormal91*

**chemistry**

A solution of household bleach contains 5.25% sodium hypochlorite, NaOCl, by mass. Assuming that the density of bleach is the same as water, calculate the volume of household bleach that should be diluted with water to make 500.0 mL of a pH = 10.23 solution.
*April 10, 2013 by sara*

**Chemistry**

A solution of household bleach contains 5.25% sodium hypochlorite, NaOCl, by mass. Assuming that the density of bleach is the same as water, calculate the volume of household bleach that should be diluted with water to make 500.0 mL of a pH = 10.10 solution.
*May 29, 2013 by JayJay*

**chemistry**

if i have a 21% solution of a product, and i need to make it a 9% solution of the same product what do i do? i am trying to dilute a product that is 21% to a 9% soultion so it can safety be used on cats. i know what to dilute it with, but i do not know how much or the math to ...
*January 19, 2016 by michele*

**chemistry**

0.02 Moles of HCl were added to a buffer solution, prepared by fluxing 20 L of gaseous NH3 and 10 L of gaseous HCl, both measured in normal conditions, in 2L of water. Calculate the pH of the solution before and after the HCl addition. (Kb NH3 = 1.8 * 10-5).
*July 5, 2016 by Anonymous*

**statistics**

Customers arrive at a movie theater at the advertised movie time only to find that they have to sit through several previews and prepreview ads before the movie starts. Many complain that the time devoted to previews is too long (The Wall Street Journal, October 12, 2012). A ...
*November 16, 2014 by sean*

**Algebra**

Checking a few answers to some algebra problems: 1.Find the slope of the line that passes through the points (-4,1) and (3,5). I got m = 5-1 / 3-(4) Answer is m = 4/7 2.Find the equation, in slope-intercept form, of the line that passes through the points (-3, 3) and (-4, 2). ...
*October 15, 2007 by John*

**Physics**

You have a solution that contains Ca2+ ions and another that contains Na+ ions. How would adding a solution that contains CO2-3 ions enable you to tell which is which?
*March 15, 2015 by Channing*

**Statistics**

28. A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that students studied an average of...
*October 22, 2011 by Steph*

**chemistry**

Hydrocyanic acid (HCN) is a much weaker acid than nitrous acid (HNO2). The pH values of 0.1 M solutions of the potassium salts of these two acids were determined separately. The statement which describes these determinations most accurately is: a. ) Both solutions are acidic, ...
*November 2, 2008 by Anonymous*

**statistics**

The average gasoline price of one of the major oil companies has been $3.20 per gallon. Because of cost reduction measures, it is believed that there has been a significant reduction in the average price. In order to test this belief, we randomly selected a sample of 36 of the...
*November 12, 2013 by Alex*

**Chemistry II**

Acetone, C3H6O, is the main ingredient of nail polish remover. A solution is made up by adding 35.0mL of acetone(d=0.790g/mL) to 50.0mL of ethyl alcohol,C2H6O(d=0.798 g/mL). Assume that the volumes are additive. From this information calculate the molarity of acetone in the ...
*September 27, 2009 by Mandy*

**chemistry **

please check if I did this right ... calculate the mass of white solid CaCO3 that forms when 98ml of a 0.1M Ca(NO3)2 solution is mixed with 54 ml of a 2.5M Na2CO3 solution. Ca(NO3)2 + 2NaCO3 -> Ca(CO3)2 + 2NaNO3 .098*0.1 =.0090 .054*2.5 =.135 limiting reactant is Ca(NO3)2 ....
*January 29, 2010 by Krissy*