# What is the percent by mass of 3.55 g NaCl dissolved in 88 g H2O? 2. A solution is made by adding 1.23 moles of KCl to 1000.0 g of water. What is the % by mass of KCl in

47,864 results
1. ## Chemistry

Calculate the mass/volume percent of a NaCl solution in which 182g of NaCl is dissolved in enough water to give a total volume of 4.78L . Would I do 182/4780ml *100?

2. ## Chemistry

A mixture contains only NaCl and Al2(SO4)3. A 1.45-g sample of the mixture is dissolved in water and an excess of NaOH is added, producing a precipitate of Al(OH)3. The precipitate is filtered, dried, and weighed. The mass of the precipitate is 0.107 g.

3. ## Chemistry

A 0.3146-g sample of a mixture of NaCl(s) and KBr(s) was dissolved in water. The resulting solution required 47.40 mL of 0.08765 M AgNO3(aq) to precipitate the Cl–(aq) and Br–(aq) as AgCl(s) and AgBr(s). Calculate the mass percentage of NaCl(s) in the

4. ## Chemistry

A 2.559 9 pellet containing NaCl and KCl is dissolved in water. A silver nitrate solution is mixed with water containing the pellet, and a precipitate forms. The precipitate is separated and dried and found to have a mass of 5.112 9. What is the percent

5. ## Chemistry

A 0.879 g sample of a CaCl2 ∙ 2 H2O / K2C2O4 ∙ H2O solid salt mixture is dissolved in 150 mL of deionized water. A precipitate forms which is then filtered and dried. The mass of this precipitate is 0.284 g. The limiting reagent in the salt mixture was

6. ## CHEM HELP

what is the theoretical mole ratio- NaCl to NaHCO3 How do you determine the percentage error of an experimental mole ratio It would be easier for us to help you if we had the entire problem instead of just parts of it. However, from the standpoint of Na,

7. ## chem

An impure sample of (COOH)2 ·2 H2O that has a mass of 3.4 g was dissolved in water and titrated with standard NaOH solution. The titration required 42.7 mL of 0.156 molar NaOH solution. Calculate the percent (COOH)2 · 2 H2O in the sample. Answer in units

8. ## Chemistry

A saline solution with a mass of 400 g has 30 g of NaCl dissolved in it. What is the mass/mass percent concentration of the solution?

9. ## Chemistry

which sample of matter is a mixture (1)H2O(s) (2)H2O(l) (3) NaCl(l) (4)NaCL(aq) please explain the answe !

10. ## AP Chemistry

(a)calculate the mass percent of carbon in the hydrated form of the solid that has the formula BeC2O4 X 3 H2O (s). I divided 24.02 g by 151.08 g and got .16, or 16%. is that correct? Also, I'm having trouble with this follow up question. When heated to 220

11. ## chemistry

What is the percent by mass of 3.55 g NaCl dissolved in 88 g H2O? 2. A solution is made by adding 1.23 moles of KCl to 1000.0 g of water. What is the % by mass of KCl in this solution? 3. If you have 100.0 mL of a 25% aqueous solution of ethanol, what

12. ## chemistry

Calculate the theoretical yield of NaCl (using mass-to-mass calculation). (Use the mass of sodium carbonate reactant used as the starting point, along with the relevant mole ratio from the balanced equation to perform this calculation). Work must be shown

13. ## chemistry

Which of the following chemical reactions represents a neutralization reaction? A. CH4 + 2O2 CO2 + H2O B. HCl + NaOH H2O + NaCl C. NH3 + H2O NH4++ OH- D. CH3COOH + H2O CH3COO- + H3O+

14. ## Chem

If you begin with 10. liters of 0.15 M NaCl, what mass of NaOH can be formed? 2 NaCl(aq) + 2 H2O(liq) ¨ H2(g) + Cl2(g) + 2 NaOH(aq)

15. ## ap chemistry

A mixture contains only NaCl and Fe(NO3)3. A .456 gram sample of the mixture is dissolved in water and an excess of NaOH is added, producing a precipitate of Fe(OH)3. The precipitate is dried and filtered, and its mass is determined to be .107 g. The mass

16. ## Chemistry

I am doing a lab online and have no clue on how to get started with the following questions? Please Help me! 1. Calculate and record the following (in grams): (a) mass of NaCl by subtraction of other components: (b) measured mass of NaCl after boiling away

17. ## Chemistry

Hi, I'm doing a chem lab of the Percent Composition of Potassium Chlorate-A Gas Law Experiment and we need to calculate the percent of KClO3 in the sample volumetrically and gravimetrically. I need help calculating the Volumetric percent of KClO3 in sample

18. ## Gen. Chemistry

A 0.887 g sample of a mixture of NaCl and KCl is dissolved in water and the solution is treated with an excess of AgNO3 producing 1.822 g of AgCl. What is the percent by mass of each component in the mixture?

19. ## Chemistry

which sample of matter is a mixture ? (1)H2O(s) (2)H2O(l) (3)NaCl(l) (4)NaCl(aq)

20. ## Chemistry

A sample of a mixture containing only sodium chloride (NaCl) and potassium chloride (KCl) has a total mass of 4.000g. When this sample is dissolved in water and excess silver nitrate is added a white precipitate (AgCl) forms. After filtration and drying,

21. ## 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.

22. ## Chemistry

1. What is the percent by mass of a solution that contains 50 grams of solute dissolved in 200 grams of solution? What is the concentration of the same solution in parts per million? 2. What is the percent mass of a solution that contains 75 grams of salt

23. ## chemistry

a solution is made by dissolving 25 g NaCl in enough water to make 1.0 L solution. Assume that density of the solution is 1.0 g/mL. calculate the mass percent, molarity, molality, and mole fraction of NaCl. whats wrong 25 g NaCl 1.0 L solution 1.0 g/mL 25

24. ## Science

In a solution, there is 1 g of NaCl for every 5 g of water. What is the ratio of sodium to water? A)1NaCl : 6H2O, because the mass of the solution equals 1 g of NaCl B)1NaCl : 5H2O, because in the solution, for every 1 g of NaCl there are 5 g of H2O

25. ## chemisty

A mixture contains only NaCl and Al2(SO4)3. A 1.76-g sample of the mixture is dissolved in water, and an excess of NaOH is added, producing a precipitate of Al(OH)3. The precipitate is filtered, dried, and weighed. The mass of the precipitate is 0.126 g.

26. ## Physical chemistry

What is the percent by weight of nacl if 1.75gm of nacl is dissolved in 58.5gm of water.

27. ## chemistry

What is the percent by mass of NaHCO3 in a solution containing 60 g of NaHCO3 dissolved in 500 mL of H2O

28. ## chemistry

An aqueous solution of nacl has a mole fraction of 0.21. What is the mass of NaCl dissolved in 100.0 mL of solution?

29. ## chemistry

A sample of CaCl2⋅2H2O/K2C2O4⋅H2O solid salt mixture is dissolved in ~150 mL de-ionized H2O. The oven dried precipitate has a mass of 0.253 g. The limiting reactant in the salt mixture is K2C2O4⋅H2O. Determine Mass of K2C2O4⋅H2O(aq) in Salt Mixture

30. ## Science

In a solution, there is 1 g of NaCl for every 5 g of water. What is the ratio of sodium to water? A) 1NaCl: 6H2O, because the mass of the solution equals 1 g of NaCl B)1NaCl : 5H2O, because in the solution, for every 1 g of NaCl there are 5 g of H2O

31. ## chemistry who helps me for me

A 0.887g sample of a mixture of nacl and kcl is dissolved in water , and the solution is then treated with an excess of agn03 to yield 1.913g of agcl. Calculate the percent by mass of nacl in the mixture 1.913/143g/mol = 0.01337 who helps me

32. ## chemistry

80g of NaCl are dissolved in 400g H2O. if the vapor pressure of the water is 40 mmHg , what is the vapor pressure of NaCl above the solution?

33. ## chemistry

a solution is made by dissolving 25 g NaCl in enough water to make 1.0 L solution. Assume that density of the solution is 1.0 g/mL. calculate the mass percent, molarity, molality, and mole fraction of NaCl. help please 25g/58.44g NaCl=.428 mol 1000 grams

34. ## chemisrty

Q4) Suppose you prepare 950 mL of a solution by dissolving 100 grams of NaCl in 900 mL of water. Assuming the density of pure water to be 1 g/mL, answer the following questions with regards to this solution: a) What is the mass percent of water in this

35. ## Chemistry

hellppp please i have a test on this on mondayy im so screwed A solid mixture contains MgCl2 and NaCl. When 0.5000 g of this solid is dissolved in enough water to form 1.000 L of solution, the osmotic pressure at 25°C is observed to be 0.4010 atm. What is

36. ## chemistry

If the solubility of NaCl at 25 degrees Celsius is 36.2 g/100 g H2O, what mass of NaCl can be dissolved in 200.0 g of H2O?

37. ## Chemistry

A mass of 0.630 g of NaCl is dissolved in 525 g of water. CAlculate the molality. mass of NaCl= 0.630g mass of H20= 525g molar mass of NaCl= 58.44 This is what i did it keeps telling me the answer is wrong. Convert grams to moles of NaCl 0.630 * 1 mol

38. ## chemistry

What is the percent by mass of 3.55 g NaCl dissolved in 88 g H2O? 2. A solution is made by adding 1.23 moles of KCl to 1000.0 g of water. What is the % by mass of KCl in this solution? 3. If you have 100.0 mL of a 25% aqueous solution of ethanol, what

39. ## CHEMISTRY

SUppose that not all of the NaCl dissolved in the water in step 7, EXPLAIN this error would affect your reported percent of: NH4Cl NaCl SiO2

40. ## Chemistry

Information beforehand: mass of weighing vial + NaCl / g 16.2597 mass of “empty” weighing vial / g 14.8136 mass of NaCl used / g Final volume of solution / L 0.2500 Questions: 1) Calculate the concentration of the NaCl solution (in mol L-1 and with the

41. ## Chemistry

A solution is made by dissolving 0.100 mol of NaCl in 5.35 mol of water. What is the mass % of NaCl? So far, I have determined molecular weight of NaCl (58.44 g/mol) multiplied by 0.100 mol = 5.844g NaCl, and mw of H2O (18 g/mol) = 96g H20. I thought mass

42. ## Chem

A bottle of win contains 12.5% ethanol by volume. The density of ethanol (C2H5OH) is .79 g/mL. Calculate the concentration of ethanol in wine as mass percent and molality. I calculated molality as 2.4 m/kg, but I'm stumped on the mass percent [although I'm

43. ## Chemistry

An impure sample of (COOH)2 · 2 H2O that has a mass of 2.9 g was dissolved in water and titrated with standard NaOH solution. The titration required 32.4 mL of 0.144 mo- lar NaOH solution. Calculate the percent (COOH)2 · 2 H2O in the sample.

44. ## chem

An impure sample of (COOH)2 · 2 H2O that has a mass of 4.3 g was dissolved in water and titrated with standard NaOH solution. The titration required 44.5 mL of 0.11 mo- lar NaOH solution. Calculate the percent (COOH)2 · 2 H2O in the sample. Answer in

45. ## chemistry

What is the freezing point (in °C) of a solution with 60.6 g of NaCl dissolved in 1050 g of H₂O? Assume complete ionization.

46. ## Science

Determine the mass % (m/m) of a NaCl solution if 58.5 grams of NaCl was dissolved in 50 ml of water (assume the density of water to be 1.0 g/ml).

47. ## chemistry

formula: 2KClO3 + NaCL = 2KCl + NaCl + 3O2 MASS OF TEST TUBE & MIXTURE = 34.03 G MASS OF EMPTY TEST TUBE = 31.29 G MASS OF MIXTURE = 2.74 G 1ST WEIGHT OF TEST TUBE & RESIDUE =33.64 G FINAL WEIGTH OF TEST TUBE & RESIDUE = 33.64 G MASS OF RESIDUE = 2.35 G

48. ## Chemistry

Separation of a mixture Lab - SiO2, NaCl, NH4Cl So step #7 was: Carefully pour off (decant) the liquid into the second evaporation dish, Adding deionized water in small amounts to the first dish and to stir it, and pour the liquid again into the second

49. ## chemisty

A mixture contains only NaCl and Al2(SO4)3. A 1.76-g sample of the mixture is dissolved in water, and an excess of NaOH is added, producing a precipitate of Al(OH)3. The precipitate is filtered, dried, and weighed. The mass of the precipitate is 0.126 g.

50. ## chem

Calculate the freezing point and boiling point of a solution that contains 57.0 g NaCl and 53.4 g KBr dissolved in 750.3 mL H2O

ClO2 is sometimes used as a chlorinating agent for water treatment. Cl2 + 4 NaClO -> 4 NaCl + 2 ClO2 In an experiment, 1L Cl2 measured at 10C and 4.66atm is dissolved in .75L of 2.00M NaClO. If 25.9g of pure ClO2 is obtained, then what is the percent yeild

52. ## chemistry

If you know that the mass concentration of a NaCl solution is 58.5 g/L, the molar concentration (mol/L) of the solution is ? can sum1 help me plz 1 mol of NaCl has a mass of what? 58.5 g NaCl x (1 mol NaCl/molar mass NaCl) = mols NaCl on 58.5 gg NaCl. Mols

53. ## Chemistry

0.7g of an unknown mixture of NaHCO3 and Na2CO3 is mixed with 3mL of 12M HCl.what is the mass of NaHCO3 and Na2CO3 in the mixture of NaHCO3 and Na2CO3? Use these equations: NaHCO3+HCl--> NaCl+CO2+H2O Na2CO3+2HCl-->2NaCl+CO2+H2O mass of mixture= mass of

54. ## chemistry

What is the percent by mass of 3.55 g NaCl dissolved in 88 g H2O?

55. ## Chemistry

Calculate the mass percent of a NaCl solution in which 158g of NaCl is dissolved in 3.81L of water at 25 ∘C (density = 0.997 g/mL).

56. ## chemistry

a mixture of NaCl and sucrose that has a combined mass of 10.20g is dissolved in enough water to make up to a 250mL solution. osmotic presdure of solution is 7.32atm at 23℃. calculate the mass percent of NaCl

57. ## chemistry

calculate the mass/volume percent of a NaCl solution in which 127g of NaCl is dissolved in enough water to give a total volume of 2.69L.

58. ## chem

the mass/volume percent of a NaCl solution in which 136 g of NaCl is dissolved in enough water to give a total volume of 4.90 L .

59. ## chemistry

What is the percent by mass of 3.55 g NaCl dissolved in 88 g H2O? 2. A solution is made by adding 1.23 moles of KCl to 1000.0 g of water. What is the % by mass of KCl in this solution? 3. If you have 100.0 mL of a 25% aqueous solution of ethanol, what

60. ## Chemistry

A sample of a mixture containing only sodium chloride (NaCl) and potassium chloride (KCl) has a total mass of 4.000g. When this sample is dissolved in water and excess silver nitrate is added a white precipitate (AgCl) forms. After filtration and drying,

61. ## Integrated Science

Hydrogen chloride (HCl) and potassium hydroxide (NaOH) react. What products are formed from this reaction? A).H2O B).NaCl C).Na+, Cl−, OH−, and H+ D).H2O, Na+, and Cl− E).H2O and NaCl I do believe the answer is E. Is this correct?

62. ## chemistry

Record and calculate the following masses: (a)mass of empty beaker: 47.420g (b)mass of beaker plus Na₂CO₃:47.920g (c)Mass of Na₂CO₃:0.5g (d)mass of beaker plus NaCl:47.438g (e) Mass of NaCl (g):0.018g **I need help with these questions below** 2.

63. ## chemistry

Making the simplistic assumption that the dissolved NaCl(s) does not affect the volume of the solvent water, determine the constants m and b in the equation Molarity = m⋅density + b that relates the NaCl molarity to the NaCl(aq) density. Take the density

64. ## chemistry

what mass of Nacl and H2o are present in 160.0g of 12 mass percentage solution of Nacl?

65. ## Chemistry

What does a saline solution of 0.9% mean quantitatively? (Per 100 gram solution; percent by mass) 0.9 g NaCl + 99.1 g H2O. Thanks!

66. ## Chemistry

1. As a research chimst, you are intrested in studying the extent and type of interactions in aqueous salt solution. As part of this study, you weight three samples of NaCl and dissolve each in 1.000kg H2O. You then measure the freezing temp. of each

67. ## Chemistry

A 0.9000g sample of a mixture NaCl and KCl is dissolved in water and the solution is then treated with an excess of AgNO3 to yield 1.933g of AgCl. Calculate the percent by mass of each compound in the mixture

68. ## Chemistry

please explain how % error and % yield would have effected the mass/moles of a substance in a reaction in a lab. In this case mass/moles of NaCl. NaHCO3+ HCl--> NaCl + CO2 + H2O

69. ## ap chem

a solution is prepared by dissolving 4.87 g of sodium dichromate in 25.0 ml of water. (d=1.00g/mL).calculate a. the mass percent of sodium dichromate in the solution. b. the mass percent o water in the solution. c the mole fraction of sodium dichromate in

70. ## Chemistry

What is the molarity of the resulting saline solution when you mix 1 mole HCl with 1 mole NaOH? I'll provide some basic information that I know, but could somebody tell me how to get the answer using the data? The balanced reaction is as follows:

71. ## Stoichiometry

Determine the mass % (m/m) of a NaCl solution if 58.5 grams of NaCl was dissolved in 50 ml of water (assume the density of water to be 1.0 g/ml).

72. ## chemistry

As a research chimst, you are intrested in studying the extent and type of interactions in aqueous salt solution. As part of this study, you weight three samples of NaCl and dissolve each in 1.000kg H2O. You then measure the freezing temp. of each solution

73. ## Chemistry

In a lab we are trying to find the percent yield of NaCl collected after evaporating the water off an NaCl solution. We made up a .100 M NaCl solution, and used 10. mL of it in our experiment. We know that the empty evaporating dish and cover mass 68.9132

74. ## Chemistry Who step by step

A 0.8870g sample of a mixture of nacl and nan03 is dissolved in water, and the solution is then treated with an excess of AGN03 to yield 1.913g of agcl. Calculate the percent by mass of the nacl in the mixture. 1.913g / 143 = 0.0133 x/58 ( 0.8870g -x) y/85

75. ## Chemistry

A .972g sample of a Cacl2 2H2O/K2C2O4 H2O solid salt mixture is dissolved in 150 ml of deionized water, previously adjusted to a pH that is basic . The precipitate after having been filtered and air dried has a mass of .375g. what is the percent by mass of

76. ## Chemistry

If 10.0g of CaCl2 and 10.0g of NaCl are dissolved in 100.0mL of solution, what is the concentration of chloride ions? (the molar mass of CaCl2 is 111.0g/mol; the molar mass of NaCl is 58.44g/mol. I found individual molar mass of: Ca-40.08 Cl-35.45 Na-22.99

77. ## Chemistry

Hello this is my first experiment I've ever done before and it was fun but I gotta figure out what NaCl produced and what it yielded in percentage. Can someone double check my work. Na2CO3+2HCl=2NaCl+H2O+CO2 Mass of empty crucible & cover: 33.076g Mass of

78. ## Chemistry

A 0.3146-g sample of a mixture of NaCl(s) and KBr(s) was dissolved in water. The resulting solution required 37.20 mL of 0.08765 M AgNO3(aq) to precipitate the Cl–(aq) and Br–(aq) as AgCl(s) and AgBr(s). Calculate the mass percentage of NaCl(s) in the

79. ## chemistry

If exactly 100.0 grams of NaCl (molecular mass = 58.44 g/mol) are dissolved in 300 grams of water (molecular mass = 18.02 g/mol), the mole fraction of NaCl is a) 1.71 b) 0.0932 c) 0.250 d) 0.103 e) 4.75

80. ## Chemistry

If 10.0g of CaCl2 and 10.0g of NaCl are dissolved in 100.0mL of solution, what is the concentration of chloride ions? I found the molar mass of CaCl2 is 111.0g/mol; the molar mass of NaCl is 58.44g/mol. I divided 10g CaCl2/111.0g CaCl2 I divided 10g

81. ## chemistry

DATA Empty Evaporating dish and watch glass: 33.6g Evaporating dish, watch glass and NaHCO3: 35.08g Evaporating dish, watch glass and product: 34.65 NaHCO3(s) + HCL (aq) ----> NaCl(s) + H2O(L) + CO2(g) 1. Determine the mass if the sodium bicarbonate

82. ## Chemistry

I Posted this question the other day: A 1.00 g sample of enriched water, a mixture of H2O and D2O, reacted completely with Cl2 to give a mixture of HCl and DCl. The HCl and DCl were then dissolved in pure H2O to make a 1.00 L solution. A 25.00 mL sample of

83. ## ap chem

I'm supposed to find the mass of NaCl in 1 L & the mass of H20 in 1 L. I'm given NaCl solution. 1% by mass. The Density is 1.071 g/mL. I know the answer for NaCl is 10.71 g, but I don't know where to start to get to this. Could you lead me in the right

84. ## Chemistry

Calculate the freezing point and boiling point of a solution that contains 55.4 NaCl and 42.3g KBr dissolved in 750.3 ml H2O

Calculate the freezing point and boiling point of a solution that contains 56.8 g NaCl and 32.0 g KBr dissolved in 750.3 mL H2O.

86. ## chemistry

The solubility of sodium chloride (NaCl) was determined experimentally to be 35.7 g/ 100 g of water (H2O) at 200 C. How many grams of NaCl would dissolve in 50g of H2O at 200 C?

87. ## chemistry

1.what is the volume of NaCl in cubic cm and cubic nm if the Length is 0.563 nm? 2. the density of NaCl is 2.17 g/cm. What is the Mass? 3. Each repeating unit is composed of 4 NaCl molecules. What is the Mass of 1 NaCl molecule?

88. ## Chemistry

Thanks in advance. A student prepared a solution of NaCl by dissolving 55.0 grams of sodium chloride in 570 mL of water. What is the percent by mass of the NaCl solution?

89. ## SCIENCE

(aq) means the solution is dissolved in water used as a solvent. (l) means the COMPOUND (not element, usually) is a pure liquid. (g) means gas and (s) means solid. In the equation below, HCl(aq) + NaOH(aq) -->NaCl(aq) + H2O(l)This means that an aqueous

90. ## chemistry

What mass of NaCl can be dissolved in 250 g of water at 20 degrees C?

91. ## Chemistry

Naoh (aq) + HCl (aq) --> NaCl (aq) + H2O (l) Using the dT determined in part 1, calculate the heat capacity of the calorimeter. Enthalpy of reaction= -58.3 kj/mol, Cs (NaCl = 3.91j/g C)density of 1 M NaCl = 1.037g/mL. dT= 12.88 degrees Celcius.

92. ## AP chemistry

8.3 grams of NaCl and 3 grams of KBr were dissolved in 47 mL of water. What is the mole fraction of KBr in the solution? I know that the mole fraction of the KBr and Nacl (without using the mL H2O is .2, but, i am confused on where i use that mL in the

93. ## Chemistry

What mass of NaCl can be dissolved in 7.50 X 10 (to the 2nd)grams of water at 25 degrees C?

94. ## Chemistry II

84.6g of NH3 are dissolved in 822g of water. What are the concentrations of this solution in mass percent and molality? Mass percent= 10.3% Molality = 6.05 Mol/kg

95. ## chemistry

50 g of NaCL is dissolved into 800 ml H2O. i need to know if is molarity, g/equivalent, freezing point depression, boiling point elevation or osmolarity. nad how to resolve please give me a hand

96. ## chemistry

50 g of NaCL is dissolved into 800 ml H2O. i need to know if is molarity, g/equivalent, freezing point depression, boiling point elevation or osmolarity. nad how to resolve please give me a hand

97. ## Chemistry 11

So I did a lab determining the chemical formula of a hydrate. We had to find the molecular formula of a hydrate of copper (2) sulphate, CuSO4 .xH2O. My observation table looks like this: Mass of clean, dry test tube: 21.6g Mass of test tube + hydrated

98. ## Chemistry

If there are 8.0 mg of dissolved O2 per liter of H2O at 20 degrees C and 1 atm, calculate the number of moles of molecular O2 and the molarity of dissolved O2 per liter of H2O.

99. ## Chemistry

How many grams of NaCl (molar mass = 58.4 g/mole) must be added to 12.0 g of water (molar mass = 18.0 g/mole) so that Xwater = 0.725? My answer was 102.69 grams of NaCl. However my friend got 14.8 grams of NaCL. We are not sure who is right? Please

100. ## science

a solution is made by dissolving 25 g NaCl in enough water to make 1.0 L solution. Assume that density of the solution is 1.0 g/mL. calculate the mass percent, molarity, molality, and mole fraction of NaCl.