Practice: What is the mass percent of NH3 of a 1.25 m aqueous solution of NH3?
| Sections | |||
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| Solutions, Molarity and Intermolecular Forces | 7 mins | 0 completed | Learn |
| Henry's Law | 20 mins | 0 completed | Learn Summary |
| Calculate Molarity | 27 mins | 0 completed | Learn Summary |
| Mass Percent | 10 mins | 0 completed | Learn |
| Molality | 15 mins | 0 completed | Learn |
| Mole Fraction | 14 mins | 0 completed | Learn |
| The Colligative Properties | 45 mins | 0 completed | Learn |
| Additional Practice |
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| Making Solutions |
| Freezing Point Depression |
| Colloid |
| Additional Guides |
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| ppm |
| The Freezing Point Depression (IGNORE) |
| Boiling Point Elevation |
Molality (m) represents the amount of solute dissolved per kilogram of solvent.
Understanding Molality
Example #1:
Molality is depicted as moles of solute per kilograms of solvent.
Concept #1: Ionic molality or osmolality represents the molality of dissolved ions in a solution.
Example #2:
A solution is prepared by dissolving 43.0 g potassium chlorate, KClO3, in enough water to make 100.0 mL of solution. If the density of the solution is 1.760 g/mL, what is the molality of KClO3 in the solution? MW of KClO3 is 122.55 g/mol.
Molality Calculations
Example #3:
If the molality of glucose, C6H12O6, in an aqueous solution is 2.56 what is the molarity? Density of the solution is 1.530 g/mL.
Example #4:
What is the ionic molality of nitrate ions in 0.305 m lead (IV) nitrate, Pb(NO3)4?.
Additional Problems
What mass (in g) of NH 3 must be dissolved in 475 g of methanol to make a 0.250 m solution?
a) 2.02 g
b) 4.94 g
c) 1.19 g
d) 8.42 g
e) 1.90 g
How many grams of potassium nitrate (KNO3) do I need to dissolve in 800. g of water to prepare a 0.425 m KNO3 solution?
What is the molality is an ascorbic acid solution made by dissolving 100.0 g of ascorbic acid, C6H8O6 (MW = 176.126 g/mol) in 750.0g of water (answers given in mole units)?
a. 1.14
b. 0.032
c. 0.0046
d. 4.3
e. 0.757
An aqueous solution is 2.67 M in HNO 3 and has a density of 1.1064 g cm –3. Compute the molality of the HNO3 in this solution in mol/kg.
a. 2.41
b. 2.97
c. 3.72
d. 2.32
e. 2.84
What is the molality of 150.0 g of NH 3 dissolved in a solution that is 1.25 Liters? The density of the solution is 1.45 g/mL.
A. 4.86
B. 5.30
C. 7.04
D. 8.28
E. 12.0
What is the molality of 150.0 g of NH 3 dissolved in a solution that is 1.25 Liters? The density of the solution is 1.45 g/mL.
A. 4.86
B. 5.30
C. 7.04
D. 8.28
E. 12.0
What is the molality of an ascorbic acid solution made by dissolving 100.0 g of ascorbic acid, C6H8O6 (MW = 176.126 g/mol) in 750.0 g of water ( answers given in molal units)?
a) 1.14
b) 0.032
c) 0.0046
d) 4.3
e) 0.757
A solution of 6.5% per weight H 2SO4 is dissolved in water. What is this concentration in molality? (Molar weight = 98 g/mol)
A. 2.3 m
B. 0.71 m
C. 4 x 10–14 m
D. 0.02 m
3.52 g NH4Cl (MW = 53.45 g/mol) is added to 12.4 g of water. Calculate the molality of ammonium chloride in the solution.
a) 5. 31 m
b) 0.0872 m
c) 15.2 m
d) 15.2 x 103 m
Calculate the molality of a solution formed by dissolving 27.8 g of LiI in 500.0 mL of water.
A) 0.394 m B) 0.556 m C) 0.241 m D) 0.254 m E) 0.415 m
What is the molality (m) of a 1.25 M aqueous solution of sugar (C 6H12O6, 342.3 g/mol) which has a density of 1.14 g/mL?
a) 0.742 molal
b) 1.25 molal
c) 0.614 molal
d) 0.966 molal
e) 1.76 molal
What mass of water is needed to dissolve 292.5 g of NaCl to produce a 0.25 m aqueous solution?
Formula Molar Mass of NaCl is 58.5 g•mol –1.
a) 20 kg
b) 5.0 kg
c) 0.80 kg
d) 0.050 kg
What mass (in g) of NH 3 must be dissolved in 475 g of methanol to make a 0.25 m solution?
A) 2.02 g
B) 4.94 g
C) 1.19 g
D) 8.42 g
E) 1.90 g
Ethylene glycol (C2H6O2) is a common automobile antifreeze, dissolving in water to make a nonelectrolytic solution.
A certain ethylene glycol solution is 30.0% by mass. What is the concentration of the solution in units of molality (m)?
Ethylene glycol (C2H6O2) is a common automobile antifreeze, dissolving in water to make a nonelectrolytic solution.
A certain ethylene glycol solution is 40.0% by mass. What is the concentration of the solution in units of molality (m)?
Molality from weight percent: What is the molality of an 18.0% aqueous solution of KCl?
An aqueous solution is 2.67 M in HNO 3 and has a density of 1.1064 g cm -3 . Compute the molality of the HNO3 in this solution in mol/kg.a) 2.42b) 2.97c) 3.72d) 2.32e) 2.84
A 9.2 M perchloric acid (HClO 4) solution has a density of 1.54 g cm -3 at 25°C. Calculate the molality of the perchloric acid.a) 5.97b) 14.2c) 10.6d) 14.9e) none of the given answers
An aqueous solution is 2.67 M in HNO3 and has a density of 1.1064 g cm -3. Compute the molality of the HNO3 in this solution in mol/kg.a) 2.76b) 2.97c) 2.84d) 3.72e) 2.32
What is the total ionic molality in an aqueous solution prepared by dissolving 0.200 moles of aluminum perchlorate, Al(ClO4)3 in 900.0 g water?
What is the molality of a 4.0 M NaOH solution? The density of the solution is 1.04 g/mL. In 1 L solution.
a) 0.15 m
b) 4.5 m
c) 0.18 m
d) 4.0 m
e) 3.8 m
What is the molality of a solution made by dissolving 38 g of C 10H8 in 425 g of C7H8? a. 0.546 mb. 12.3 mc. 0.998 md. 4.65 me. 0.698 m
A solution of ethanol, C2H6O, is prepared by dissolving 14.0 g C2H6O in 100.0 g water. (Molar mass ethanol = 46.07 g/mole) Find the molality of the solution.
Calculate the molality of a 23.0% by mass acetic acid, HC 2H3O2, solution. (molar mass = 60.05 g/mole)
How many grams of glucose (C6H12O6) must be dissolved in 563 g of ethanol (C2H5OH) to prepare a 2.40 x 10 -2 m solution?A. 2.43 g C6H12O6B. 4.32 g C6H12O6C. 0.000075 g C6H12O6D. 437 g C6H12O6E. 7.69 C6H12O6
30 grams of liquid ethanol, CH3CH2OH, are mixed with 70 g water. The density of pure ethanol is 0.789 g/mL. The density of water is 1 g/mL. What is the molality of the ethanol in this solution?
Which of the following statements is FALSE?a) The minority component of a mixture is called the soluteb) The majority component of a mixture is called the solventc) A diluted solution contains a relatively small amount of solute relative to solventd) The molarity of a solution is the moles of solute divided by liters of solvente) The molality of a solution is the moles of solute divided by kg of solvent
What is the molality of naphthalene (C10H8) when 10.5 g of the compound are dissolved in 325 g of benzene (C6H6)?
A. 0.252 m
B. 0.0819 m
C. 13.4 m
D. 32.3 m
What mass (in g) of NH3 must be dissolved in 475g of methanol to make a 0.250 m solution?
If an aqueous solution is very dilute, will its molality be greater than its molarity, nearly the same as its molarity, or smaller than its molarity?
What is the molality of a 32.0% by weight aqueous solution of acetone (C 3H6O)?A. 8.10B. 7.80C. 7.12D. 6.56E. 5.74
The density of a 20.3 M CH 3OH (methanol) solution is 0.858 g/mL. What is the molality of this solution? H2O is the solvent. a) 20.8 m b) 97.8 m c) 17.4 m d) 23.7 m e) 70.0 m
A solution was prepared by dissolving 39.0 g of KCl in 225 mL of water. Calculate the molality of KCl in the solution.
Calculate the molality of total ions in an aqueous solution prepared by dissolving 0.400 moles of magnesium chloride in 850.0 g of water.A. 0.47 x 10-4 mB. 1.41 x 10-4 mC. 1.41 mD. 0.47 mE. 0.941 m
Determine the molality of an aqueous solution prepared by dissolving 0.112 moles of LiCl in 13.7 moles of H 2 O.A) 0.122 mB) 0.454 mC) 0.220 mD) 0.818 mE) 0.153 m
What mass (in g) of NH3 must be dissolved in 475 g of methanol to make a 0.250 m solution?
How many moles of KF are contained in 244 mL of 0.135 m KF solution? The density of the solution is 1.22 g/mL
A solution of sucrose (C12H22O11 of MW 342 grams/mole) in benzene is 0.40 molal. The solution’s density is 0.90 grams/mL. How many milliliters of the solution would contain 0.10 moles of sucrose?1. 444 mL2. 316 mL 3. 250 mL4. 360 mL5. 225 mL
Your lab partner combined chloroform (CHCl3) and acetone (C3H6O) to create a solution where the mole fraction of chloroform, Xchloroform is 0.187. The densities of chloroform and acetone are 1.48 g/mL and 0.791 g/mL, respectively. a) Calculate the molarity of the solution. b) Calculate the molality of the solution.
What is the mole fraction, X, of solute and the molality, m (or b), for an aqueous solution that is 11.0% NaOH by mass?
At 20°C, a 0.376 M aqueous solution of ammonium chloride (NH 4Cl) has a density of 1.0045 g/mL. What is the molality of NH4Cl in the solution?A. 0.774B. 2.68C. 0.385D. 0.00710E. 2.00