Friday

July 29, 2016
Number of results: 30,627

**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*

**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*

**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**

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*

**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*

**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*

**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*

**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**

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*

**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*

**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**

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*

**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*

**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*

**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*

**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*

**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*

**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**

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*

**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*

**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*

**chemistry**

A 0.15M solution of weak triprotic acid is adjusted (base added) so that the pH is 9.27(you can assume minimal volume change). The triprotic acid(H3A) has the following acid ionization constants: Kal=1.0*e-3, ka2=1*e-8,ka3=1*e-12. which species given below is present in the ...
*May 13, 2011 by vivanh*

**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*

**College Chemistry (DrBob222)**

You have 120.0 mL of a 0.245 M solution of NaCl in an open beaker. After several days, you test the solution and find that it now has a concentration of 0.348 M. How much water must have evaporated from the beaker given the new concentration?
*March 25, 2014 by Anonymous*

**chemistry**

A student weighs out 0.568 g of KHP (molar mass = 204 g/mol) and titrates to the equivalence point with 36.78 mL of a stock NaOH solution. What is the concentration of the stock NaOH solution? KHP is an acid with one acidic proton. a. 3.15 M b. 0.0757 M c. 0.943 M d. 0.100 M ...
*October 12, 2014 by mathew*

**Math ---HELP!!!!!**

sample of nine students is selected from among the students taking a particular exam. The nine students were asked how much time they had spent studying for the exam and the responses (in hours) were as follows: 18, 7, 10, 13, 12, 16, 5, 20, 21 Estimate the mean study time of...
*May 30, 2016 by angela*

**Probability and Statistics**

The proportion of adults living in a small town who are college graduates is estimated to be p = 0.6. To test this hypothesis, a random sample of 15 adults is selected. If the number of college graduates in the sample is anywhere from 6 to 12, we shall not reject the null ...
*November 29, 2013 by Katy*

**Probability and Statistics**

The proportion of adults living in a small town who are college graduates is estimated to be p = 0.6. To test this hypothesis, a random sample of 15 adults is selected. If the number of college graduates in the sample is anywhere from 6 to 12, we shall not reject the null ...
*November 30, 2013 by Katy*

**Probability and Statistics**

The proportion of adults living in a small town who are college graduates is estimated to be p = 0.6. To test this hypothesis, a random sample of 15 adults is selected. If the number of college graduates in the sample is anywhere from 6 to 12, we shall not reject the null ...
*November 30, 2013 by Katy*

**math,correction**

can you check if how i solved it to show that my answer is no is correct. Is -4 a solution to the equation 7x-5+3x=6+x-10 This is what i did: 7(-4)-5+3(-4)=6+(-4)-10 -28-5-12=2-10 -45=-8 so the answer is no -4 is not the solution to the equation. Yes this is fine yes this is fine
*February 13, 2007 by jasmine20*

**Chemistry**

How would you prepare 150.0 mL of a 0.200 M aqueous solution of potassium chloride from a 0.500 M aqueous solution of potassium chloride?
*November 21, 2010 by Kiesha*

**chemistry**

is the following false the boiling point of a 0.5 aqueous solution of koh is higher than the boiling point of a 0.5m aqueous solution of kcl?
*December 2, 2010 by micki*

**chemistry**

if 10 ml of a 2M standard solution is used to neutralize 20mL of an unknown base what is the molarity of the unknown and is this standard solution an acid or base?
*June 7, 2011 by jessica*

**Chem 151**

A solution of ammonia and water contains 3.50×10^25 water molecules and 5.00×10^24 ammonia molecules. How many total hydrogen atoms are in this solution?
*September 13, 2011 by Tyler*

**chemistry**

A chemist wants to make 5.50 L of a 0.300 M lithium phosphate solution. What mass of lithium phosphate must be used to make this solution?
*November 3, 2014 by James*

**Chemistry**

What is the molarity of a solution that contains 2.17 moles of (SrCl2) in 2,660ml of solution? I know that the formula is molarity=moles/liters Liters=.2660
*June 21, 2015 by Ocean*

**chemistry**

Suppose 70.00 mL of a lithium hydroxide, LiOH, solution requires 55.42 mL of a 0.1050 M solution of propanoic acid, C2H5COOH, for neutralization. LiOH + C2H5COOH ® C2H5COOLi + H2O What is the concentration of the base solution? 0.08313 M 0.1663 M 0.3325 M 0.6650 M Question 2 4...
*October 9, 2010 by hope*

**Chemistry**

Redox Titrations I did a redox titration of NaBO3 with KMnO4. I used a .0545 M NaBO3 solution, and an average of .026 L of .01M KMnO4. I have to standardize the KMnO4 solution, does anyone know how to do this?
*March 25, 2009 by Ryan*

**Chemistry**

Trichloroacetic acid (CCl3CO2H) is a corrosive acid that is used to precipitate proteins. The pH of a 0.050 M solution of trichloroacetic acid is the same as the pH of a 0.040 M HClO4 solution. Calculate Ka for trichloroacetic acid.
*November 23, 2011 by Kaleen*

**mixture**

Sugar solution is composed of 40 grams of sugar and 200 grams of water. How many grams of sugar must be added to make a 60% sugar solution? (Kindly write the equation..... tnx)
*November 22, 2012 by HELP HELP MNHS*

**chemistry**

You have a solution that contains 340ml of water and 20ml of ethanol. Find the concentration of ethanol in this solution in each of the following units: (density of water is 1.00 g/ml, density of ethanol is 0.789g/ml)
*February 18, 2014 by Anonymous*

**chemisty problem help**

Carbon-12 contains 6 protons and 6 neutrons. The radius of the nucleus is approximately 70 pm. Calculate the volume of the nucleus and the volume of the atom. What percentage of the carbon atom's volume is occupied by the nucleus? Can someone tell me how to do this? Volume= 4/...
*February 8, 2007 by Tagen*

**Thin Layer Chromotography**

Can you use TLC to distinguish various isomers from one another? In what kind of substance can you NOT distinguish the isomers from each other? i think it is not possible to distinguish If I have an unknown sample containing several ketones and want to use TLC to identify the ...
*November 5, 2006 by Sarah*

**chemistry**

a new compound composed of just Hex-Nuts and bolts is formed.A 13.7 Kg sample of the new compound is separated into its component elements with the following result 3.84 kg. of hex-nuts and 9.90 kg of bolts. 1. How many hex-nuts are present in the 13.7 kg sample 2. how many ...
*October 10, 2012 by Amanda*

**chem**

a new compound composed of just Hex-Nuts and bolts is formed.A 13.7 Kg sample of the new compound is separated into its component elements with the following result 3.84 kg. of hex-nuts and 9.90 kg of bolts. 1. How many hex-nuts are present in the 13.7 kg sample 2. how many ...
*October 22, 2012 by Amanda*