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

27,836 results
1. ## chemistry

When 50.0mL of 1.20 M of HCl (aq)is combined with 50.0mL of 1.30 M of NaOH (aq) in a coffee-cup calorimeter, the temperature of the solution increases by 8.01 Degrees C. What is the change in enthalpy for this balanced reaction? HCl(aq) + NaOH(aq)

2. ## chemistry

If you dilute 10.0mL of the stock solution to a final volume of 0.350L , what will be the concentration of the diluted solution?

3. ## chemistry

Four solution are prepared and mixed together: Start with 100.0ml of 0.100M BaCl2. Add 50.0ml of 0.100M AgNO3. Add 50.0ml of 0.100M H2So4. Add 250.0ml of 0.100M NH4. Write an equation for any reaction that occurs after each step and calculate the

4. ## chemistry

If 25.0mL of 0.56 M H2SO4 is diluted to a volume of 125 mL, what is the molarity of the resulting solution?

5. ## Chemistry

WOULD THE VOLUME OF A 0.10M NAOH SOLUTION NEEDED TO TITRATE25.0ML OF A 0.10M HNO2 ( A WEAK ACID)SOLUTION BE DIFFERENT FROMTHAT NEEDED TO TITRATE 25.0ML OF A 0.10M HCL (A STRONGACID)SOLUTION?

6. ## corrected repost chemistry

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

7. ## Chemistry

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

8. ## Chemistry

I need to figure out the molarity in the problem. A) 3.60g of sulfuric acid in 450.0mL of solution I was going to take 3.60 / 450.0mL = 0.008 B) 2.0 x 10-3 mol Iron(II)nitrate in 12.0mL of Solution 10 *3=30 then I was going to take 30*2.0 =60 60/12.0= 5 I

9. ## chem

Calculate the final concentration of a. 4.0 L of a 4.0 M HNO3 solution is added to water so that the final volume is 8.0L b. Water is added to 0.35L of a 6.0M KOH solution to make 2.0L of a diluted KOH solution. c.A 20.0 mL sample of 8.0% (m/v)NaOH is

10. ## chemistry

A solution is prepared by dissolving 0.5842g of oxalic acid (H2C2O4) in enough water to make 100.0ml of solution. A 10.00ml aliquot (portion) of this solution is then diluted to a final volume of 250.0ml. What is the final molarity of thus prepared oxalic

11. ## Chemistry

Determine how many mL of solution A (acetic acid-indicator solution) must be added to solution B (sodium acetate-indicator solution) to obtain a buffer solution that is equimolar in acetate and acetic acid. Solution A: 10.0 mL 3.0e-4M bromescol green

12. ## Chemistry

Determine the volume, in milliliters, required to prepare each of the following diluted solutions. 40.0mL of a 2.75M KNO3 solution using a 1.00M KNO3 solution 45.0mL of a 2.90M H2SO4 solution using a 6.00M H2SO4 solution 0.700L of a 2.10M NH4Cl solution

13. ## AP Chemistry

A chemist mixes 200.0mL of 0.800 M Fe(NO3)3 and 300.0 mL of 0.750 M K2Cr04 and enough of either 0.400 M KOH or 0.400 M Pb(no3)2 to end up with only two spectator ions in solution. a. How much precipitate will be formed b. How many mL of KOH or Pb(No3)2

14. ## chem

The pH of saturated Sr(OH)2 is found to be 13.12. A 15.0ml sample of saturated Sr(OH)2 is diluted to 250.0ml in a volumetric flask. A 15.0ml sample of the diluted Sr(OH)2 is transferred to a beaker, and some water is added. The resulting solution requires

15. ## Chem

When 20.0mL of 1.40M solution of calcium nitrate is mixed with 70.0mL of 0.234M potassium iodate, a precipitate Ca (IO3)2 is formed. Calculate the concentrations of both NO3- and IO3- before mixing and after mixing.

16. ## Chemistry

A 60.0ml 0.513M glucose solution is mixed with 120.0ml of 2.33 M glucose solution. What is the concentration of the final solution. assume volumes are additive.

17. ## Chenistry

Be able to calculate the pH of a solution prepared by mixing 50.0mL of 0.200M NaH2PO4 (pKa2=7.20) with 50.0mL of 0.120M NaOH. I did work out a pH of 7.38 but I am not sure if i need to take into account any dilution of the mixing of solutions and do you

18. ## Chemistry (Help)

0.275gAgNO3 is dissolved in 500mL of solution. a. What is the molarity of this solution. b. If 10.0 mL of this solution are transferred to a flask and diluted to 500mL, what is the concentration of the resulting solution? c. If 10.0mL of the solution in

19. ## Chemistry

Then calculate the inital ClO^- concencentrations for 1st, 2nd, and 3rd reactions. Calculate [ClO^-] in a 6% bleach solution. A 6% bleach solution contains 6 grams of NaClO per 100 grams bleach. The density of 6% bleach is 1.07g/mL. Chemical reaction: Blue

20. ## Chemistry

A stock solution of sulfuric acid must be diluted by adding 25.0mL of 7.50M H2SO4 to enough water to make 500mL of diluted soultion. What is the concentration of the diluted solution?

21. ## Chemistry

a domestic cleaner contains concentrated hydrochloric acid as the active ingredient. a titration experiment was carried out to determine the concentration of hydrochloric acid in the domestic cleanser. 20.0mL of the cleanser were diluted to 250.0mL with

22. ## chemistry

If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

Please help to determine the (%w/w) benzoyl peroxide (C14H20O4) in a sample. Procedure: 2.500g of sample was dissolved in 75ml dimethylformamide and diluted to 100.0ml with the same solvent. (Solution T). To 5.0ml of Solution T, 20ml of acetone and 3ml of

24. ## chm

Calculate the PH OF A SOLUTION prepared by mixing 15.0mL OF 0.50 M OF NaOH AND 30.0mL OF 0.50 M BENZOIC ACID SOLUTION?( Benzoicacid is monoprotic and its dissociation constant is 6.5*10^-5)

25. ## Chemistry

A 15.0mL solution of H2SO3 is neutralized by 12.0mL of a standardized 1.00M NaOH solution. What is the concentration of the H2SO3 solution? Please reply with the steps on how to do this question so I can learn. I can't find examples or anything related in

26. ## Chemistry

the following acid—base neutralization reaction HNO3 (aq)+ KOH (aq) --KNO3(aq) + H2O (I) What is the molarity (M) of an HNO3 solution if 50.0ml is needed to react with 25.0ml of 0.150M KOH solution?

27. ## 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

28. ## Science

A 5.0ml aliquot of a sample was transferred to a 25.0ml flask and acidified by addition of 2.5ml of 0.1M HClO4 and diluted to mark. 1.0ml of that solution was mixed with 5.0ml of 1 X 10-4M AYR(Aluminum)dye and 15.0ml ethanol in a 25.0ml flask and diluted

29. ## Chemistry

Please help, I can't do this and its stressing me out ?!?! A 25.0 mL aliquot of an aqeuous quinine solution was diluted to 50.0mL and was found to have an absorbance of 0.832 at 348nm when measured in 2.00cm cell. A second 25.0mL aliquot was mixed with

30. ## chemistry

The pH of saturated is found to be 13.12. A 15.0mL sample of saturated Sr(OH)2 is diluted to 250.0mL in a volumetric flask. A 15.0 mL sample of the diluted Sr(OH)2 is transferred to a beaker, and some water is added. The resulting solution requires 27.6mL

31. ## chemistry

2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

32. ## chemistry

2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

33. ## Chemistry (Dilution) Help please?

Calculate how to prepare 100.0mL of a 1.25x10^-4 M aqueous solution of Fe(NO3)3(aq) by dilution of stock of 0.0025M Fe(NO3)3(aq) in a 100.0mL volumetric flask? I tried using the m1v1=m2v2 equation but it doesn't look like that equation would work for this

34. ## chemistry

calculate the pH of the solution when 25.0ml of 0.0920M HCL is titrated with 0.15ml, 23.0ml, 30.0ml of 0.10M NaOH

35. ## Chemistry

How many grams of lead(ii)iodide are generated when 400.0ml of 1.25M NaI reacts with 525.0ml of 1.00M Pb(NO3)2 according to the following balanced equeation? 2NaI + Pb(NO3)2---> 2NaNO3 + PbI2

36. ## Chemistry

How do you prepare 600.0mL of 0.48M Al(NO3)3*9H2O? Is this correct? 1. Measure out 71g of solution 2. Put approx. 300.0mL of water into container 3. Add the 71g of solution to the water and mix 4. Add more water until 600.0mL of solution is obtained 5. Mix

37. ## Chemistry

How do you prepare 600.0mL of 0.48M Al(NO3)3*9H2O? Is this correct? 1. Measure out 71g of solution 2. Put approx. 300.0mL of water into container 3. Add the 71g of solution to the water and mix 4. Add more water until 600.0mL of solution is obtained 5. Mix

38. ## Chemistry

I do not know how to solve this problem. Could you show me how? You have a stock solution of 5.00M H3PO4. a.) What would be the concentration if 20.0mL of the stock solution is diluted to 250.0mL? b.) What volume of the dilute solution would you need if

39. ## chemistry

If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

40. ## Chem Urgent

Volume of stock solution a. 5.0mL b.10.0mL c.15.0mL d.20.0mL Prepare 25mL of each of the four different dilute solution Concentration of stock- 1.01E-5 Calculate molarity for a,b,c,d Molarity=m1V1/V2 for a would the answer be 2.02E6?????

41. ## Chemistry Lab

So I did a kinetics lab on the rate of reaction of peroxydisulfate ion with iodide ion. Part 1 was the effect of concentration. One of the questions asked is to calculate the amount of thiosulfate consumed in moles. My results for trial 1 were (Times taken

42. ## chem

A 75.0mL sample of 1.56×10−2M Na2SO4(aq) is added to 75.0mL of 1.22×10−2M of Ca(NO3)2(aq). What percentage of the Ca+ remains unprecipitated?

43. ## AP Chemistry

If 15.0mL of 2.50M NaCl is mixed with 60.0mL of 0.300M Pb(NO3)2, what is the mass of the precipitate

44. ## chem

A 75.0mL sample of 1.56×10−2M Na2SO4(aq) is added to 75.0mL of 1.22×10−2M of Ca(NO3)2(aq). What percentage of the Ca+ remains unprecipitated?

45. ## Chemistry

When 20.0mL of 1.40M solution of calcium nitrate is mixed with 70.0mL of 0.234M potassium iodate, a precipitate Ca (IO3)2 is formed. Calculate the concentrations of both NO3- and IO3- before mixing and after mixing

46. ## chemistry

A 250.0mL sample of 0.0012M Pb(No3)2 (aq) is mixed with 150.0mL of 0.0640M Na (aq) should precipitation of PbI2 (s) ,Ksp=7.1¡Á10^-9, occur?

47. ## science

Which of the following samples will react completely with 20.0 mL of 0.200 M LiOH 10.0ML of 0.100 M HCL 10.0mL of 0.200 M H2SO4 10.0mL of 0.100 M HNO3 20.0mL of 0.200 M H3PO4 20.0mL of 0.100 M HBr How do I do this problem??

48. ## chemistry

2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

49. ## chemistry

2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

50. ## chemistry

If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

51. ## science

To 90.0mL of a solution that contains 0.100M Cr(NO3)2 and 0.490M HNO3 is added 30.0mL of 0.170M K2Cr2O7. The dichromate and chromium(II) ions react to give chromium(III) ions. Write a balanced net ionic equation for the reaction.

52. ## Chemistry

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this

53. ## Chemistry

From your Dilution Data in the procedure 3 and 4, calculate the initial concentration of Fe3+ (aq) ion for tubes 2-5. 1. Add 5.00ml of 1.00 x10^-3 M KSCN to all tubes. 2. To test tube 1 add 5 ml of 0.200M Fe(NO3)3. 3. Measure 8.00ml of 0.200M Fe(NO3)3 into

54. ## Chemistry

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this

55. ## Chemistry

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this

56. ## Chemistry

A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 2. Calculate the % concentration of this

57. ## Chem (ques 2)

The analysis of some household cloudy ammonia cleaner involved diluting a 50.0mL sample of the cleaner to a volume of 250.0mL then titrating this diluted solution. The diluted sample was found to have an NH3 (aq) concentration of 0.350 mole per L. What is

58. ## Chemistry

A 36.0mL sample of 1.20 M KBr and a 56.0mL sample of 0.700 M KBr are mixed. The solution is then heated to evaporate water until the total volume is 60.0mL. What is the molarity of the KBr in the final solution?

59. ## Chemistry

A 36.0mL sample of 1.20 M KBr and a 56.0mL sample of 0.700 M KBr are mixed. The solution is then heated to evaporate water until the total volume is 60.0mL. What is the molarity of the KBr in the final solution?

60. ## Chemistry

If 15.0ml of a 6.0M HCl solution is diluted to 75.00ml, what is the molarity of the diluted solution?

61. ## chemistry

What is the mole ratio of the reactants in a tube containing: Pb(NO3) 22.0mL 0.5 mol NaI 16.0mL 0.5 mol

62. ## Chemistry

Suppose we have a solution of lead nitrate, Pb(NO3). A solution of NaCl(aq) is added slowly until no further precipitation occurs. The precipitate is collected by filtration, dried and weighed. A total of 10.27g of PbCl2(s) is obtained from 200.0mL of the

63. ## chemistry

What's the percentage of the H202 that has been consumed if you use 11.5ml of water, 3.0ml buffer, 2.5ml KI, 1.0ml starch, 1.0ml Na2S203.and 1.0ml H202

64. ## Chemistry

what is the molar concentration of h2so4 solution is 2.0ml of which is completely neutralized by 45.0ml of 0.115 mol/L NaOH solution?

65. ## Chemistry- Drbob-help

I have placed the answer I got please help. A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter. 1. What is the volume of this solution? 870mL

66. ## Chemistry

Calculate the pH of the solution formed by adding 15.0ml of 0.1M sodium hydroxide to 30.0ml of 0.1M propanoic acid.

67. ## chemistry

You have a 1.0 M stock solution of H2SO4 in a large flask. You need to dilute this to make a 0.25M solution of H2SO4 for an experiment. If you need exactly 100.0mL of the diluted solution, how would you make the diluted solution?

68. ## chemistry

You are given a 25.0mL volumetric flask, describe the procedure you will follow in lab to prepare 25.0mL of a 0.019 M solution of NaCl?

69. ## Chemistry

What is the molarity of the solution prepared by diluting 25.0ml of 0.220M NaCl to 75.0ml of final volume?( explain your steps)

70. ## chemistry

You are given a 25.0mL volumetric flask, describe the procedure you will follow in lab to prepare 25.0mL of a 0.019 M solution of NaCl?

71. ## Chemistry

a 20.0ml sample of HCL solution is placed in a flask with a few drops of indicator. If 30.0ml of a 0.240 M NaOH solution is needed to reach the endpoint, what is the molarity of the HCL solution?

72. ## analytical chemistry

Calculate the ph during the titration of 20.0ml 0.5000M ethanoic acid Ka=0.0000175 with 0.500M NaOH after the addition of 0.0ml and 10.0ml NaOH

73. ## Chemistry- acids/bases

Find the concentration of OH- of a solution of 45.0mL of 0.0921 M Ba(OH)2 diluted with enough water to make 350.0 mL of solution.

74. ## Chemistry- acids/bases

Find the concentration of OH- of a solution of 45.0mL of 0.0921 M Ba(OH)2 diluted with enough water to make 350.0 mL of solution.

75. ## Chemistry

Titration of a 21.0mL solution of requires 11.0mL of 0.0350M solution. What is the molarity of the solution?

76. ## Chemistry

To what volume should you dilute 43.5mL of a 4.20M KI solution so that 24.0mL of the diluted solution contains 2.80g of KI? Please if you can explain it to me I am so confused.

77. ## Chemistry- Drbob-help#3

I still need help with #3 I'm not sure how I got 1.14M. I have tried to do the problem over, but I not coming up with my original answer of 1.14M. Somehow I am missing a step. Please show work for the 1.14M Thanks Question#9 reads exactly as written. A

78. ## Chemistry

If 50.0mL of 1.60M HCl was added to 50.0mL of 1.80M NaOH, calculate the molarity of the resulting NaCl solution. (Hint: resulting solution has a volume of 100 mL)

79. ## Chemistry

If 50.0mL of 1.60M HCl was added to 50.0mL of 1.80M NaOH, calculate the molarity of the resulting NaCl solution. (Hint: resulting solution has a volume of 100 mL)

80. ## Chemistry

Suppose that 50.0mL of 0.240M sulfric acid requires 36.0mL of KOH solution to reach its endpoint. What is the molarity of the KOH solution?

81. ## Chemistry

A student dissolved the KHP in 100.0mL of water instead of 50.0mL. Will the molar concentration of the NaOH solution determined from titrating be greater, less than, or unaffected by this mistake? Explain.

82. ## chemistry

Pb(NO3)2 6.0mL 0.5 mol NaI 12.0mL 0.5 mol What is the mole ratio between Pb(NO3)2 and NaI?

83. ## chemistry

to what volume should you dilute 125mL of an 8.00M CuCl2 solution so that 50.0mL of the diluted solution contains 5.9g KNO3 I have a hard time determing the M1V1=M2V2 is

84. ## Chemistry

If 25.0mL of sodium nitrate solution (0.100mol/L) is added to 10.0mL of sodium carbonate solution (0.150 mol/L), what is the concentration of sodium ions in the resulting mixture? Assume the volumes are additive.

85. ## Chemistry

you have75.0ml of 2.5 M Solution of Na2CrO4(aq). You also have 125ml of a 1.74M solution of AgNO3(aq)Calculate the concentration of NO3 when the two solutions are added together

86. ## Chemistry & Math

If you add 1.0ml (cm3) of a aqueous solution of NaCl at 0.4mol to 9.0ml of water what's the final concentration of NaCl in mmol? ty

87. ## Chemistry

Can you show me how to calculate this equation? What is the concentration of phosphoric acid solution of 30.0ml of a 0.2M of Potassium hydroxide is used to neutralize. The volume of acid is 20.0ml.

88. ## Chemistry

You pipetted 15.0mL of Na2CO3(aq). You then added 20.0mL of Sr(NO3)2(aq). Your dry filter paper was 1.69g. You filter paper and precipitate is 3.76g. What is the concentration of the Na2CO3(aq)?

Hi, sorry I missed out something. The titrant used was 0.100M Sodium thoiosulphate.Do I have to consider its concentration in the calculations? Thanks a lot. Posted by angela on Tuesday, August 3, 2010 at 6:58pm. Please help to determine the (%w/w) benzoyl

90. ## Chemistry

When 50.0mL of 0.100M NH3 (Kb=1.8x10^-5) solution is mixed with 20.0mL of of 0.250M HCl solution, what is the pH after reaction? I solved the ka=5.56x10^-10 and I solved the moles of each nHCl and nNH3 and both have 0.005 moles. What do I do after this?

91. ## Chemistry

When 50.0mL of 0.100M NH3 (Kb=1.8x10^-5) solution is mixed with 20.0mL of of 0.250M HCl solution, what is the pH after reaction? I solved the ka=5.56x10^-10 and I solved the moles of each nHCl and nNH3 and both have 0.005 moles. What do I do after this?

92. ## chem

A sample of 45.0 ml of 0.750M AgNO3 solution is added to 65.0ml of 1.375M Cr(NO3)3 solution. Calculate the resultant concentration of nitrate ions in the mixture.

50.0mL of 0.1 molar NaOH is added with 50.0mL of 0.1 molar CH3COOH. The Ka = 1.8*10^-5. what is the pH of the solution? a) 7.00 b) 9.22 c) 4.77 d) 8.22 e) 5.78 I think that the answer is d. Would i be safe in saying that?

94. ## Chemistry

Can anyone help me identify the solute and solvent in each solution with the steps if possible? Thanks! a. 10mL of acetic acid and 200mL of water b. 100.0g of water and 5.0g of sugar c. 1.0mL of Br2 and 50.0mL of methylene chloride

95. ## Chemistry

Suppose that 2.00mL of 0.02 mol/L aqueous sodium sulphide, Na2S is used to test a 60.0mL sample of water containing 0.0004 mol/L mecury (II) nitrate Hg(NO3)2, ions. a. Write the balanced equation Hg(NO3)2 + Na2S = HgS + 2NaNO3 b. Determine the limiting

96. ## chemistry

Suppose that 2.00mL of 0.02 mol/L aqueous sodium sulphide, Na2S is used to test a 60.0mL sample of water containing 0.0004 mol/L mecury (II) nitrate Hg(NO3)2, ions. a. Write the balanced equation Hg(NO3)2 + Na2S = HgS + 2NaNO3 b. Determine the limiting

97. ## 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

98. ## chemistry

a 35.0ml sample of 37 hcl solution has a density of 1.18g/ml. the sample is diluted to a volume of 0.125L. what is the molarity of the final solution ?

99. ## chemistry

a 35.0ml sample of 37% hcl solution has a density of 1.18g/ml. the sample is diluted to a volume of 0.125L. what is the molarity of the final solution ?

100. ## Chemisty

(I am a mom trying to help my child had Chem years ago if I can see how this is doNE I can explain it to them) You have 70.0mL of a .400M stock solution that must be diluted to .100M. How much water should I add?