Tuesday

January 17, 2017
Number of results: 31,693

**algebra**

eq1 y = 2x + 3 eq2 y = 1x + 2 What is the solution for eq1 and eq 2? Remember we are looking for the "common" x and y pairs that solve BOTH equations. Are any of the following (x,y) pairs a solution to the above systems of equations? (2, 4) ? (-1, 1) ? Why?

*March 16, 2011 by bianca, pleeease help i'm lost*

**Chemistry**

How much 12 M HCl do you add to 1 L of water to obtain 0.2 HCl? Use this same approach to do the math for the dilution of 5.5 M of barium hydroxide solution to 0.5 M barium hydroxide solution.

*February 19, 2012 by Amanda*

**Chemistry**

How much 12 M HCl do you add to 1 L of water to obtain 0.2 HCl? Use this same approach to do the math for the dilution of 5.5 M of barium hydroxide solution to 0.5 M barium hydroxide solution.

*February 19, 2012 by Amanda*

**chemistry(Please Check)**

You dissolve 6.55 g of potassium nitrate in enough water to make a 250. mL solution. What is the molarity of this solution ?Answer: 0.0262 Please Check my answer

*April 23, 2012 by Wurola*

**Chemistry**

A glucose solution contains 55.0g of glucose C6H12O6 in 475g of water. Compute the freezing point and boiling point of the solution. Assume a density of 1.00g/mL for water.

*September 18, 2012 by Monica*

**Chem**

In the lab a 3.3mol per liter solution was prepared by adding H2O to 140mL of a 4.3mol Per Liter solution of HCL. How much water was added?

*March 19, 2014 by BILL*

**Science**

80ml of methyl alcohol water are mixed to give a solution that has a final volume of 154ml. What is the concentration of the solution expressed as percent by volume methyl alcohol?

*July 7, 2014 by Araceli*

**Algebra**

Find the values of a in the domain of f for which f(a)equals the given number. (If there is no solution, enter NO SOLUTION.) f(x) = x2 − 4x − 19; f(a) = 13 a = ____ (smaller value) a = ____ (larger value)

*October 13, 2014 by Kim*

**Chemistry **

Make 50.0 mL of a 0.500 M solution of acetic acid (CH3COOH) from the 1.00 M CH3COOH using a 50.0 mL graduated cylinder. 1. Show your calculations and explain how you made the acetic acid solution.

*February 25, 2015 by Kate*

**SCIENCE**

Indicate how to mix two of the first concentration 3.2 M hydrochloric acid solution and the second to 15% by weight and density 1.30Kg / L to obtain 2.5 L of hydrochloric acid solution in 4.2M concentration

*February 17, 2016 by ATTILIA*

**Chem 205**

A solution of ammonia and water contains 3.50×1025 water molecules and 9.00×1024 ammonia molecules. How many total hydrogen atoms are in this solution? Any help would be appreciated, thank you!

*September 11, 2016 by Melissa*

**Chemistry **

The concentration of ammonium ion in the solution of the salt called ferrous ammonium sulfate, formula [Fe(NH4)]2(SO4)3, is 0.360 M. The concentration of sulfate ions in this solution is?

*September 27, 2016 by Colby*

**chemistry**

Assume that it is necessary to determine the [FE^3+ in a solution that may be 0.0001 to 0.0005 M range . Outline the spectrophotometric method that would accurately give the required data. Be spectific about the solutions that you would use. I know I have to work up a ...

*November 13, 2016 by jxv*

**Statistics**

Suppose the U.S. president wants an estimate of the proportion of the population who support his current policy toward revisions in the Social Security system. The president wants the estimate to be within 0.028 of the true proportion. Assume a 99 percent level of confidence. ...

*March 31, 2013 by Adam Dane*

**NEED HELP!**

A mixture contained CaCO3 and MgCo3. A sample of this mixture weighing 7.85g was reacted with excess HCl. The reactions are-- CaCO3 + 2HCl --> CaCl2 + H2O + CO2 MgCO3 + 2HCl --> MgCl2 + H2O + CO2 Is the sample reacted completely and produced 1.94L of CO2, at 25 degrees C...

*November 5, 2009 by Mary*

**chemistry help!**

A mixture contained CaCO3 and MgCo3. A sample of this mixture weighing 7.85g was reacted with excess HCl. The reactions are-- CaCO3 + 2HCl --> CaCl2 + H2O + CO2 MgCO3 + 2HCl --> MgCl2 + H2O + CO2 Is the sample reacted completely and produced 1.94L of CO2, at 25 degrees C...

*November 6, 2009 by Mary*

**Science- Chemistry**

A test tube containing a mixture of compounds X, Y, and a small amount of Z weighs 25.4886 g. The tube is emptied into a beaker and the empty tube is reweighed, giving a value of 10.2586 g. The mixture is separated into two components by dissolving in water, filtering off the ...

*October 13, 2012 by Sonia*

**CHEMISTRY PLEASE HELP**

Using the data collected for part c on your data sheet and assuming the density of the vinegar is 1.00g/mL, 1) calculate the molar concentration of acetic acid (CH3COOH) in the vinegar sample using the average volume of NaOH. 2) calculate the mass percent of acetic acid in the...

*October 24, 2011 by Josh*

**Chemistry**

How do you calculate alkalinity in chemistry? Ex: List the values for total alkalinity for Sample A and Sample B A 104 drops of titrant (5.25mL) 3 drops of C20 H14 O4 B 81 drops of titrant (4.25mL) 3 drops od C20 H14 O4

*August 15, 2016 by anon*

**Math**

Suppose that you have a supply of a 25% solution of alcohol and a 75% solution of alcohol. How many quarts of each should be mixed to produce 90 quarts that is 60% alcohol?

*January 29, 2013 by Chanelle*

**chemistry**

A nitric acid solution containing 71.0% by mass of the acid has a density of 1.42g/ml how many grams of nitric acid are present in 1.0L of this solution

*May 3, 2013 by cheryl*

**sails math**

A chemist has a solution that is 70% acid and another that is 45% acid. How many liters of each should he mix to obtain 300 liters of a solution that is 65% acid?

*April 29, 2016 by Brooke*

**Biology**

In class, I did an experiment with water and iodine solution in a beaker and also starch in a dialysis tube tied and placed in the beaker. There were discussion questions I couldn't answer surely... please check my answers. 1. a)Use your results to determine the direction of ...

*April 3, 2012 by CrissyXD*

**chem**

Liquids A and B form an ideal solution. A certain solution contains 25 mole % of A, whereas the vapor in equilibrium with the solution at 25 degrees C contains 50. mole % of A. The heat of vaporization of A is 5 kcal/mol; that of B is 7 kcal/mol. a) Calculate the ratio of the ...

*March 28, 2007 by Chris*

**Chemistry**

Concentrated sulfuric acid is 18.4 molar and has a density of 1.84 grams per milliliter. After dilution with water to 5.20 molar the solution has a density of 1.38 grams per milliliter. This concentration of H2SO4 is often used in lead storage batteries(like a car battery). 1....

*January 13, 2011 by K*

**Statistics **

The number of books sold over the course of the three-day book fair were: 365, 303, 401. Assume that samples of size 2 are randomly selected with replacement from this population of three values. a. List the different possible samples, and find the mean of each of them. b. ...

*July 20, 2015 by Elizabeth*

**chemistry**

how would i calculate; a 50g sample of water at 100 degrees is poured into a 50g sample of water at 25 degrees. with a specific heat of water (l) being 4.184 j/g degrees C.what will be the final temperature of the water? heat gained + heat lost = 0 [massH2O*specificheat*(Tf-Ti...

*January 14, 2007 by Noreen*

**Chemistry **

40.0 ml of an acetic acid of unknown concentration is titrated with 0.100 M NaOH. After 20.0 mL of the base solution has been added, the pH in the titration flask is 5.10. What was the concentration of the original acetic acid solution? (Ka(CH3COOH) = 1.8 × 10−5)

*April 10, 2011 by Bob*

**Chemistry**

Compound Z has a MW of 100. Your lab partner weighed 25 grams of compound Z and dissolved it in water to a final volume of 1 liter. a) What is the concentration of the solution expressed as a percentage by weight (w/v)? b) What is the concentration of the solution expressed as...

*August 29, 2011 by Ty*

**Chemestry**

Have two tanks of 100 liters each, with salt solution. One is at 9% and 4% other. How many liters at least must be removed from each container, so that upon mixing which is removed to obtain a 7% solution of salt concentration?

*June 4, 2013 by RFT*

**chemistry**

use the Henderson-Hasselbalch equation to calculate the pH of a buffer solution prepared by mixing equal volumes of 0.20 M NaHCO3 and 0.10M Na2CO3.(Ka=5.6x10^-11). how would you prepare NaHCO3-Na2CO3 buffer solution that has the pH of 10.40.

*February 28, 2014 by abc*

**AP Chemistry**

The Ksp of Ni(CN)2 is 3.0 × 10−23. What is the molar solubility of Ni(CN)2 in a 0.065 M KCN solution? Answer in units of mol/L. I found that the normal molar solubility is 1.957x10^-8, but I don't know how the KCN solution affects it. Sig figs aren't accounted for.

*January 20, 2015 by Q*

**chemistry**

You wish to prepare 100.0 mL of a 800.0 ppm w/v sodium (MW = 22.9897 g/mol) solution. How many grams of sodium dichromate dihydrate (Na2Cr2O7·2H2O, MW = 297.998 g/mol) are needed to prepare this solution?

*January 26, 2015 by Chase*

**Math Check**

Hi! Can someone check these two answers? Thanks! Directions: Find the correct number of solutions for the following system of equations. 1.) 5x - 3y + 2z = 3 2x + 4y-z = 7 x - 11y + 4z = 3 2.) 2x + y- 3z = 4 4x + 2z = 10 -2x + 3y - 13z = -8 A.) One Solution B.) Infinitely Many...

*March 6, 2015 by Gigi*

**chemistry**

Calculate the approximate pH of a 0.1 M solution of ethanoic acid at 298 K, given that the dissociation constant, Ka, is 1.75 x 10-5 mol/L at 298 K.Ethanoic acid dissociates in aqueous solution as follows: CH3COOH(aq) + H2O H3O+(aq) + CH3COO-(aq)

*April 28, 2015 by Emily*

**Chemistry**

If you try to carry out a double displacement reaction by mixing together equal volumes of a solution that contains dissolved NaF and a solution that contains dissolved NaCl. Would you expect a reaction? Why or why not?

*November 28, 2016 by Rebecca*

**Chemistry**

Phthalic acid, H2C8H404, is a diprotic acid used in the synthesis of phenolphthalein indicator. Ka1= 1.2x 10^-3, and Ka2 = 3.9 x 10^-6. a) Calculate the hydrongen-ion concentration of a .015 M solution. b) What is the concentration of the C8H4O4^2- ion in the solution?

*November 29, 2016 by Crystal*

**Statistics**

The president of a bank selected a sample of 1500 applications to check if the approval or rejection of an application depends on which one of the two loan officers handles the application. The information obtained from the sample is summarized in the following 2 way table. ...

*April 16, 2013 by Bettie*

**Chemistry**

Using the data collected for part c on your data sheet and assuming the density of the vinegar is 1.00g/mL, 1) calculate the molar concentration of acetic acid (CH3COOH) in the vinegar sample using the average volume of NaOH. 2) calculate the mass percent of acetic acid in the...

*October 24, 2011 by Josh*

**math **

Ok, so when you are solving an equation, and you have an answer such as 5x=0 , does that mean that it is no solution or all real #s? And, when the answer is 4=4 , does that mean it is no solution or all real #s? And when the answer is 2x=2x, does that mean it is no solution or...

*May 7, 2013 by K*

**physics**

Define STPD, ATPD, BTPS and list the values. I'm in college and our books haven't came in from the bookstore. I don't understand how the prof. is still making us do this HW. my younger brother told me I should try to get help from this site since it helped him. This is all I ...

*January 27, 2008 by jamie*

**Chemistry Check Please!**

A solution is prepared by dissolving 3.44 g of sucrose, C12H22O11, in 118 g of water. a) What is the molality of the resulting solution? b) What is the mole fraction of water in this solution? B) moles of h2o=118g/18(g/mol)=6.5556 mol moles of c12h22O11= 3.44g/342.3(g/mol)=0....

*January 16, 2014 by Kate *

**Statistics**

part 2 - An entertainment company owns and operates movie theaters in Wyoming. The president of the company is concerned that film rentals are hurting the business. They directed a staff member to estimate the total number of films rented by households in wyoming in a ...

*March 2, 2007 by Jason L*

**institute of health sciences**

Chemistry A) determine the mass of sodium hydroxide needed to prepare 100ml of 0.5M standard solution B) describe the procedure used to prepare the standard solution C) use the 100ml stock solution of 0.5M sodium hydroxide to neutralize H2SO4 by volumetric analysis I) ...

*November 12, 2015 by trendy*

**Stats**

Childhood participation in sports, cultural groups, and youth groups appears to be related to improved self-esteem for adolescents. (McGee, Williams, Howden-Chapman, Martin & Kawachi, 2006). In representative study, a sample of n = 100 adolescents with a history of group ...

*November 16, 2016 by Adriana*

**chemistry**

Iron(II) can be oxidized by an acidic K2Cr2O7 solution according to the net ionic equation. Cr2O72− + 6 Fe2+ + 14 H+ 2 Cr3+ + 6 Fe3+ + 7 H2O If it takes 44.0 mL of 0.0250 M K2Cr2O7 to titrate 25.0 mL of a solution containing Fe2+, what is the molar concentration of Fe2+?

*March 3, 2011 by Robert*

**chemistry**

A 100.0 mL portion of 0.250 M calium nitrate solution is mixed with 400.0 mL of .100M nitric acid solution. What is the final concentration of the nitrate ion? BOB PURSLEY PLEASE EXPLAIN MORE THOROUGHLY HOW YOU GOT THE NITRATE ION TO BE .5M

*October 24, 2010 by alex*

**pcc**

A volume of 40.0mL of aqueous potassium hydroxide (KOH) was titrated against a standard solution of sulfuric acid (H2SO4). What was the molarity of the KOH solution if 21.7mL of 1.50 M H2SO4 was needed? The equation is 2KOH(aq)+H2SO4(aq)→K2SO4(aq)+2H2O(l)

*July 15, 2013 by jose*

**Chemistry**

A volume of 80.0mL of aqueous potassium hydroxide (KOH) was titrated against a standard solution of sulfuric acid (H2SO4). What was the molarity of the KOH solution if 21.7mL of 1.50 M H2SO4 was needed? The equation is 2KOH(aq)+H2SO4(aq)→K2SO4(aq)+2H2O(l)

*February 24, 2014 by carley*

**organic chemistry**

a compound you have prepared is reported in the literature to have a pale yellow color. when the substance is dissolved in hot solvent to purify by crystallization, the resulting solution is yellow. explain if you should us decolorizing charcoal before allowing the solution to...

*August 25, 2008 by mekonen*

**chemistry**

the molar heat capacity of water at 25 degrees celsius is 75.29JK/mol. an exothermic reaction with -5.00kJ proceeded to completion in a 200mL dilute aqueous solution,initially at 16.0 degrees celsius. what is the final temperature of the solution ? clearly show all working

*April 11, 2012 by ayanda*

**Physical Sciences**

I have a project practical investigation to do and I have no idea how to go about with it. The problem is: Calculate the mass of sodium hydroxide used to prepare a 0,5M NaOH solution in a 250ml volumetric flask. Determine the concentration of the acetic acid solution used (...

*August 10, 2012 by Cindy*

**General Chemistry.**

The absorbance of a chlorophyll a standard solution in ethanol (density = 0.785 g/mL) is measured in a 1.3 cm cuvette or path length. The absorbance is 0.765 and the molar absorptivity coefficient is 86,300 M–1cm–1. The molecular weight for chlorophyll a is 893.49 g/mol. ...

*November 7, 2012 by Shardae.*

**chemistry clearly step by step**

Al2(s04)3 solution of 1 molal concentration is present in 1 litre solution of 2.684g/cc.How many moles of bas04 would be precipitation on adding bacl2 in excess? The answer 6M I do not understand pls explain step by step Thank a lot all tutors

*July 20, 2014 by Ken*

**chem**

You mix 5.32 g of solid magnesium sulfate with 105.24 g of water inside a calorimeter. As the magnesium sulfate dissolves, the temperature of the solution rises from 24.5°C to 30.1°C. Calculate the amount of energy in kJ that was transferred into the surroundings through ...

*November 11, 2015 by Anonymous*

**chemistry**

a student was investigating the properties of a liquid L. He found that it turned phenolphthalein indicator red but when a piece of litmus paper was dipped into liquid L it turned blue. Which of these liquids could it be? a Aqueous ammonia b Lemon juice c copper sulphate ...

*February 18, 2016 by vidya*

**chemistry**

In a solution of Al2(SO4)3 the Al3+ concentration is .12 M. What mass of Al2(SO4)3 is in 50 mL of this solution. Please explain the steps. Thanks. The Al3+ part confuses me the most.

*August 26, 2011 by Van M*

**algebra **

Which has a Unique solution, No solution, or infinitely many solutions? 1. 2X + 3 = 9 2. 9X+ 2 = 9X+ 2 3. (1/2X+3) = (1/3x+9) 4. (x+2)(x+3) = x*x (x squared) + 5x + 6 5. 2(2x+3) = 4x+6 my guess is 1. unique 2. no 3. unique 4. unique 5. infinite 6. infinte but I know at least ...

*September 16, 2010 by Pam*

**CHEMISTRY- boiling point**

0.1m aqueous solution of HCl and 0.1m aqueous solution of C6H12O6. calculate the boiling point of each i know the eq. dTb=Kbm but i have no temperatures. this is the question

*October 15, 2010 by lulu78*

**Chemistry**

If you begin with 100.0 mL of a 3.0 Molar solution of ammonium sulfate and 100mL of a 2.0 Molar solution of barium phosphate how many grams of Barium sulfate would be produced?

*February 10, 2011 by jackie*

**chemistry**

If you begin with 100.0 mL of a 3.0 Molar solution of ammonium sulfate and 100mL of a 2.0 Molar solution of barium phosphate how many grams of Barium sulfate would be produced?

*February 10, 2011 by jackie*

**Chemistry**

Urea, (NH2)2CO, is dissolved in 73.5 g of water. The solution freezes at -0.095°C. How many grams of urea were dissolved to make this solution? (Answer must be in grams)

*March 29, 2011 by Irma*

**chem**

How many liters of 12.3 molar NaOH stock solution will be needed to make 12.4 liters of a 1.2 molar NaOH solution? Show the work used to solve this problem.

*April 6, 2011 by jose*

**Math**

If a system has an infinite number of solutions, use set-builder notation to write the solution set. If a system has no solution, state this. 6x − 2y = 2, 9x − 3y = 1

*August 5, 2011 by Anonymous*

**Chemistry**

How many grams of CO2 would be produced from the following reaction sequence? HI + KHCO3 -> KI + H2CO3 H2CO3 -> H2O + CO2 if 20.0 ml of 1.00 M KHCO3 solution is mixed with 20.0 ml of 1.50 M HI solution.

*November 15, 2011 by Kristi*

**Chemistry**

Predict the color change when an aqueous solution containing Ag+ ion is added to a green solution of the copper (II) ion. It is green because HCL has been added. Thanks.

*March 28, 2012 by Kate*

**Chemistry**

A solution of ammonia and water contains 2.90×1025 water molecules and 9.00×1024 ammonia molecules. How many total hydrogen atoms are in this solution? any help would be great.

*September 8, 2012 by Pam*

**Chemistry**

How would a student make 500.0 mL of a 0.08500 M solution of iron(III) using a stock solution that is 0.3180 M in iron(III)? Explain how this would be done.

*November 21, 2012 by Gabby*

**Chemistry**

Suppose a solution containing 4.50g of sodium phosphate is mixed with a solution containing 3.75g of barium nitrate. How many grams of barium phosphate can be produced?

*August 6, 2013 by Stockton*

**chemistry heelp **

What volume of a solution that is 15.7 % (w/w) lolinic acid (density = 1.64 g/mL) contains 4.25 g of lolinic acid15. What is the molarity of a 20.2 % (w/w) solution of rossonic acid (423.6 g mol-1) that has a density of 1.78 g mL-1?

*January 31, 2014 by nene *

**Chemistry**

A solution contains 5.6g of solute in 16 cm cubed of water. When the solution is cooled, crystals begin to appear at 11 degrees celsius. What is the solubility of the solute at 11 degrees celsius?

*September 29, 2014 by Caoilfhinn*

**chemistry**

A solution contains 5.00g of urea per 0.100kg of water (COCNH2)2 if the vapour pressure of pure water at 25°c is 23.7ton. What is the vapour pressure of the solution

*January 27, 2015 by Opite*

**Chemistry**

A student mixes 764 mL of water and 476 mL of 1.00 x 10-5 M orange food dye solution. What is the concentration of this new dilute solution of orange food dye?

*July 5, 2015 by George*

**math**

Which statement concerning the equation x^2+2=x is true? Its discriminant is 0 , so it has no solution. Its discriminant is 0 , so it has one real solution. Its discriminant is -7, so it has two complex solutions. Its discriminant is -7, so its solutions are negative.

*May 9, 2016 by Claire*

**Chemistry**

Your lab partner tells you that he has prepared a solution that contains 1.5 moles of NaOH in 1.5 L of aqueous solution, and therefore that the concentration of NaOH is 1.5 M. (a) Is he correct (b) If not what is the correct concentration

*September 10, 2016 by John*

**Statistics- quick! Is this right?**

I need to verify one of my answers quickly...the problem is: The mean annual salary for classroom teachers is $43,658. Assume a standard deviation of $8000. 1) Determine the sampling distribution of the sample mean for a sample of size 256. Interpret your answer in terms of ...

*November 1, 2007 by Laura*

**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 should it be? 2) What...

*October 1, 2011 by anonymous*

**Chemistry 12**

9. According to Arrhenius, which of the following groups contain: i)only acids ii)only bases a. NaOH, H2CO3, KCl b. MgCl2, H2SO4, HCl c. HNO3, HCl, H3PO4 d. Mg(OH)2, AgBr, HF e. KOH, NH4OH, Ba(OH)2 10. Enough water is added to 100 g of sodium hydroxide in order to obtain a one...

*May 22, 2011 by Kavitha*

**statistics**

The average age of evening students at a local college has been 21. A sample of 19 students was selected in order to determine whether the average age of students had increased. The average age of the students in the sample was 23 with a standard deviation of 3.5. Determine ...

*January 4, 2011 by carrie*

**math URGENT!**

28. You are surveying students to find out their opinion of the quality of food served in the school cafeteria. You decide to poll only those students who buy hot lunch on a particular day. Is your sample random? Explain. 29. Ira wants to determine the fast–food restaurant ...

*April 27, 2012 by jksl*

**Math**

A candidate for a political office claims that he will win the election. A poll is conducted, and 35 of 150 voters indicate that they will vote for the candidate, 100 voters indicate that they will vote for his opponent, and 15 voters are undecided. a. What is the population ...

*October 10, 2011 by Jen*

**physics**

The half-life of Th(227) is 18.72 days. It decays by alfa emission to Ra(223), an alfa emitter whose half-life is 11.43 days. A particular sample contains 10^6 [10E(+6)] atoms of Th(227) and no Ra(223) at time t=0. a) How many atoms of each type will be in the sample at t=15 ...

*November 6, 2014 by Mag*

**chem!**

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 the right formula? or no?

*May 16, 2007 by Mistra*

**Chemistry**

If 0.250 moles of NaOH are dissolved in 125g of water, what is the %m/m of NaOH in this solution? I converted 0.250 mol to 10.0 g. Then using the equation mass solute/mass solution * 100 I came up with the final answer of 7.41 %m/m. Is that correct?

*April 29, 2008 by Jen*

**science**

Please check my work 3M solution of NaOH (1 liter worth) molecular weight: 39.99 3 x 39.99= 119.97 grams dilute to 1000mL 3 M solution of HCl (1 L) c1v1=c2v2 (12M)(?)= (3M)(1000mL) ?= 250 mL please check thank you

*October 13, 2008 by ag*

**chem**

what precautions should be observed when an aqueous sodium carbonate solution is used to extract an organic solution containing traces of acid? is it that aqueous sodium carbonate is extremely combustible, which can't be exposed to an open flame?

*October 28, 2008 by Jason*

**chem**

what precautions should be observed when an aqueous sodium carbonate solution is used to extract an organic solution containing traces of acid? is it that aqueous sodium carbonate is extremely combustible, which can't be exposed to an open flame?

*October 28, 2008 by Jason*

**chemestry**

an aqueous solution was prepared by dissolving 1438.0g of a nonelectrolyte in 469.0g of water at 25*c. the Vapor pressure of the resulting solution was found to be 20.5 torr. what is the molar mass of the unknown compound? the vapor pressure of the water at 25*c is 23.76torr.

*March 2, 2011 by Nick*

**chemistry**

A graduated cylinder was used to transfer 201 mL of a 0.478 M solution of KCl to a beaker which was subsequently diluted to a final volume of 1.092 L. What is the final molarity of the KCl in the beaker after the solution is thoroughly mixed?

*February 8, 2012 by Alex*

**Chemistry**

A solution of 1.50g of solute dissolved in 25.0 mL of H2O at 25C has a boiling point of 100.95C. What is the molar mass of the solute if it is a nonvolatile non electrolyte and the solution behaves ideally. (d of H2O at 25C=0.997g/mL)?

*February 12, 2012 by Tori*

**ap chemistry**

A voltaic cell made of a Cr electrode in a solution of 1.0 M in Cr 3+ and a gold electrode in a solution that is 1.0 M in Au 3+ . a) Provide the half cell reactions for each of the electrodes. b) Which is the anode and which is the cathode? How did you decide? c) Give an ...

*April 17, 2012 by megan*

**Chemistry**

When sulfuric acid reacts with ammonia solution an ammonium salt and water are produced. Calculate the volume of 3mol/dm3 of acid required to react exactly with 25ml of a 2.5mol/dm3 of ammonia solution.

*June 5, 2012 by Jeconiah*

**pre-calculus**

solve the equation 1. In x + In (x+12) =2 x= ? or either there is no solution 2. solve the exponential equation 9^x=6 What is the exact answer? 3. Use transformations to indentify the graph of the function. Then determine its domain, range, and horizontal asymptote. f(x)=2^-x+...

*October 6, 2012 by ladybug*

**chem**

A solution is prepared by dissolving 25 grams of sodium sulfate in enough water to give a total volume of 500. mL. The molar mass of sodium sulfate is 142 grams per mole. What is the molarity of the solution?

*November 14, 2012 by jennifer*

**chemistry (Pls Bob check for me)**

A 150 mg/dl glucose solution was diluted 1:2. Then 0.5ml of it was added to 4.5ml saline 2 ml of this solution was diluted to 10ml. What is the final concentration of glucose? 1L= 10dl 1dl =100mL Answer 0.015mg/dl

*March 16, 2013 by Fai*

**chemistry**

How would you prepare a solution of about 8mg/100ml of ascorbic acid in water (25ml)? I'm not sure if they mean to use that ratio of ascorbic acid in water to make a 25 ml solution or if the wording means something else.

*February 22, 2014 by solution chemistry*

**Chemistry**

A 1.50 L buffer solution is 0.250 mol L-1 in HF and 0.250 mol L-1 in NaF. Calculate the pH of the solution after the addition of 0.0500 moles of solid NaOH. Assume no volume change upon the addition of the base. The Ka for HF is 3.5 × 10-4. Thanks in advance!

*June 21, 2015 by B*

**chemistry **

Choose the pair of substances that are most likely to form a homogeneous solution. N2O4 and NH4Cl C6H14 and C10H20 LiBr and C5H12 C6H14 and H2O None of the pairs above will form a homogeneous solution.

*February 3, 2016 by reem*

**Gen Chem**

A mixture of NaCl and sucrose (C12H22O11) of combined mass 10.2 g is dissolved in enough water to make up a 250 mL solution. The osmotic pressure of the solution is 8.29 atm at 23°C. Calculate the mass percent of NaCl in the mixture.

*February 4, 2016 by Brittany*

**Math...PLEASE HELP!!!!**

A candidate for a political office claims that he will win the election. A poll is conducted, and 35 of 150 voters indicate that they will vote for the candidate, 100 voters indicate that they will vote for his opponent, and 15 voters are undecided. a. What is the population ...

*October 9, 2011 by Jen*