Having hard time wit these questions. Will provide a thumbs up if answered corre
ID: 1006458 • Letter: H
Question
Having hard time wit these questions. Will provide a thumbs up if answered correclty.(please answer all 34 questions)
1.A salt sample is placed into some water and nearly all of it dissolves without stirring or heating. The resulting solution is:
saturated.
supersaturated.
unsaturated.
impossible to determine.
2.A bottle of vodka is labeled as 60. proof. What is its alcohol content expressed as (v/v)%?
A.60.%
B.15%
C.30.%
D.7.5%
3.A solution is produced in which water is the solvent and there are four solutes. Which of the solutes can dissolve better if the solution is heated?
Oxygen
Sodium bicarbonate
Argon
More than one response is right.
4.Iodine, I2, is very slightly soluble in water, a polar solvent, but quite soluble in toluene, a nonpolar solvent. What can be inferred about the nature of the I2 molecule?
It is ionic.
It is polar.
It is nonpolar.
Nothing can be inferred.
5.As NH4NO3 dissolves in water, the resulting solution becomes colder. Which of the following expressions is most correct?
NH4NO3 + heat NH4+ + NO3- + heat
heat + NH4NO3 NH4+ + NO3-
NH4NO3 NH4+ + NO3-
NH4NO3 NH4+ + NO3- + heat
6.A certain salt is known to have a solubility in water of 32.6g/100g water at 100°C and 11.7g/100g water at 20°C. The salt is dissolved in 240 g of water at 100°C until no more solid will dissolve. How much salt will crystallize out when the solution is cooled to 20°C?
32.6 g
28.1 g
11.7 g
78.2 g
50.2 g
7.If we know the solute and the molarity of a solution which other concentration unit can we readily determine without any other measurements?
A.%(w/w)
B.%(w/v)
C.%(v/v)
D.all of these
8.Which of the following concentration units will not change if the solution is heated?
A.%(w/v)
B.%(w/w)
C.both a and b
D.neither a nor b
9.If 9.25 g Ca(NO3)2 is dissolved in enough water to make 0.300 L of solution, what is the molar concentration of Ca(NO3)2?
0.188 M
30.8 M
59.1 M
3.08×10-2 M
0.302 M
10.A solution is made by dissolving 5.84 grams of NaCl in enough distilled water to give a final volume of 1.00 L. What is the molarity of the solution?
0.400
1.00
0.0250
0.100
11.A solution is made by combining 4.00 g of sugar and 100 mL of water (density = 1.00 g/mL). What is the concentration in % w/w?
3.85
4.00
0.0400
26.0
12.If a solution is prepared by dissolving 7.7 g of lithium iodide, LiI, in enough water to make 400. mL of solution, what is the %(w/v) of LiI?
A.7.7%
B.1.9%
C.3.9%
D.0.96%
13.How many grams of solid KCl are needed to prepare 250 mL of 0.235 M solution?
4.38
31.3
15.6
9.32
14.Calculate the number of moles of ZnCl, in 100 mL of 0.300 M solution.
3.00
0.300
30.0
3.00 × 10-2
15.An ion in solution that is surrounded by water is a(n) ____ ion.
colloid
osmotic
saturated
hydrated
16.Which of the following is a description of a hydrated salt?
A.a salt with water incorporated in its crystal structure
B.a salt which is soluble in water
C.a salt with no water incorporated in its crystal structure
D.a salt which is insoluble in water
17.Which of the following would be considered a strong electrolyte?
Salt
Sugar
Acetic acid
All of the choices are correct.
18.Citric acid, a natural food preservative, accounts for the tartness of citrus fruits. It is shown below. About 730 g of this material can be dissolved in water, making a liter of solution. However, only about 1.5% of it dissociates. As such, it would be considered a _____.
weak electrolyte
strong electrolyte
pseudoelectrolyte
nonelectrolyte
19. The more soluble a substance is, the faster it will dissolve.
True
False
20.Which of the following is a description of an anhydrous salt?
A.a salt with water incorporated in its crystal structure
B.a salt which is soluble in water
C.a salt with no water incorporated in its crystal structure
D.a salt which is insoluble in water
21.A 0.9% NaCl (w/w) solution in water is:
produced by mixing 0.9 moles of NaCl in a 100 moles of water.
produced and has the same final volume as a 0.9% solution in ethyl alcohol.
a solution that boils at or above 100°C.
All of these responses are correct.
22.Which of the following tend to stabilize colloids and prevent suspended particles from settling?
Presence of emulsifying agents
Absorption of charges by colloid particles
Absence of ionic salts
More than one response is correct.
23.Which of the following is not considered a colligative property?
Freezing point
Boiling point
Conductivity
Vapor pressure
24.A colligative property:
will only occur for aqueous solutions.
depends only on the number of species added to a solution.
results from increasing vapor pressure as a solute is added to a solvent.
All of the choices are correct.
25.Changes in boiling point, freezing point, and vapor pressure are
the same at 1 atm as at 1.55 atm.
the same for 50 mL of 2 M NaCl as they are for 250 mL of 1 M NaCl.
the same for 75 mL of 2 M NaCl as they are for 50 mL of 2 M NaOH.
the same for 2 M NaCl as they are for 2 M CaCl2.
26.Given three solutions, each of which contains 1.0 g of solute dissolved in 100 mL of water, which of the following solutes will cause the solution to have the lowest freezing point?
A.ribose, C5H10O5
B.glucose, C6H12O6
C.sucrose, C12H22O11
D.All have the same freezing point.
27.What is the underlying process involved in dialysis?
An electrical potential separates the blood from the impurities.
Osmosis is due to a difference in solution concentrations.
Pressure is applied to the blood squeezing out the impurities.
Mixtures are homogenous.
28.The rate of osmosis:
can be increased by having larger pores in the membrane.
can be increased by removing the membrane.
can be increased by an increase in the atmospheric pressure.
cannot be increased by any of the responses.
29.Which of the following pass through both osmotic and dialysis membranes?
Solvent molecules
Large molecules
Cations
Anions
30.What is the osmotic pressure of a 0.050 M solution of AlCl3 in water that is at 0.00°C? Consider AlCl3 to be a strong electrolyte.
3.4 × 103 torr
1.1 atm
2.2 atm
8.5 × 102 torr
31.An isotonic salt solution is 0.90% (w/w) NaCl in water. How many grams of NaCl are contained in 1.00 kg of such a solution?
90
0.90
9.0
0.090
32.Which of the following is associated with cells in a hypertonic solution?
A.crenation
B.hemolysis
C.reverse osmosis
D.none of these
33.Given three solutions, each of which contains 1.0 g of solute dissolved in 100 mL of water, which of the following solutes will cause the solution to have the highest osmolarity?
A.ribose, C5H10O5
B.glucose, C6H12O6
C.sucrose, C12H22O11
D.None, they all have the same osmolarity.
34.Which of the following aqueous solutions will have the highest osmolarity?
A.0.1 M ethylene glycol, C2H6O2
B.0.1 M glucose, C6H12O6
C.0.1 M sucrose, C12H22O11
D.All have the same osmolarity.
Explanation / Answer
1.A salt sample is placed into some water and nearly all of it dissolves without stirring or heating. The resulting solution is:
Answer: saturated.
2.A bottle of vodka is labeled as 60. proof. What is its alcohol content expressed as (v/v)%?
Ans: the percentage of alcohol is half of proof, so 30%
3.A solution is produced in which water is the solvent and there are four solutes. Which of the solutes can dissolve better if the solution is heated?
Ans: a solid can dissolve more on heating, so sodium bicarbonate
4.Iodine, I2, is very slightly soluble in water, a polar solvent, but quite soluble in toluene, a nonpolar solvent. What can be inferred about the nature of the I2 molecule?
Ans: it is non polar
5.As NH4NO3 dissolves in water, the resulting solution becomes colder. Which of the following expressions is most correct?
Ans: reaction is endothermic so
heat + NH4NO3 NH4+ + NO3-
6.A certain salt is known to have a solubility in water of 32.6g/100g water at 100°C and 11.7g/100g water at 20°C. The salt is dissolved in 240 g of water at 100°C until no more solid will dissolve. How much salt will crystallize out when the solution is cooled to 20°C?
Ans: the maximum amount of salt that can be dissolved in 240 grams of water at 20°C = 11.7 X 2.4 = 28.08 grams
The amount of salt dissolved at 100°C = 78.24 grams
so amount ppt out = 78.24-28.08 = 50.16 g
32.6 g
7.If we know the solute and the molarity of a solution which other concentration unit can we readily determine without any other measurements?
B.%(w/v)
8.Which of the following concentration units will not change if the solution is heated?
B.%(w/w)
9.If 9.25 g Ca(NO3)2 is dissolved in enough water to make 0.300 L of solution, what is the molar concentration of Ca(NO3)2?
Ans: Molarity = Mass / Molecular mass X volume of solution = 9.25 / 164.08 X 0.3 = 0.188 M
10.A solution is made by dissolving 5.84 grams of NaCl in enough distilled water to give a final volume of 1.00 L. What is the molarity of the solution?
Molarity = Mass / mol wt X volume = 5.84 / 58.5 X 1 = 0.0998 M = 0.1 M
11.A solution is made by combining 4.00 g of sugar and 100 mL of water (density = 1.00 g/mL). What is the concentration in % w/w?
%w/w = mass of sugar X 100 / total mass of solution = 4 X 100 / 104 = 3.85%
12.If a solution is prepared by dissolving 7.7 g of lithium iodide, LiI, in enough water to make 400. mL of solution, what is the %(w/v) of LiI?
%w/v = 7.7 X 100 / 400 = 1.9%
13.How many grams of solid KCl are needed to prepare 250 mL of 0.235 M solution?
Mass required = Molarity X volume(L) X molecular weight = 0.235 X 74.5 X 0.25 = 4.38 grams
14.Calculate the number of moles of ZnCl, in 100 mL of 0.300 M solution.
Moles = Molarity X volume in litres = 0.300 x 0.1 = 0.03 moles = 3.00 × 10-2
15.An ion in solution that is surrounded by water is a(n) ____ ion.
hydrated
16.Which of the following is a description of a hydrated salt?
A.a salt with water incorporated in its crystal structure
17.Which of the following would be considered a strong electrolyte?
Salt
18.Citric acid, a natural food preservative, accounts for the tartness of citrus fruits. It is shown below. About 730 g of this material can be dissolved in water, making a liter of solution. However, only about 1.5% of it dissociates. As such, it would be considered a _____.
weak electrolyte
19. The more soluble a substance is, the faster it will dissolve.
True
20.Which of the following is a description of an anhydrous salt?
C.a salt with no water incorporated in its crystal structure
21.A 0.9% NaCl (w/w) solution in water is:
a solution that boils at or above 100°C.
22.Which of the following tend to stabilize colloids and prevent suspended particles from settling?
Presence of emulsifying agents
Absorption of charges by colloid particles
Absence of ionic salts
More than one response is correct.
23.Which of the following is not considered a colligative property?
Conductivity
24.A colligative property:
All of the choices are correct.
25.Changes in boiling point, freezing point, and vapor pressure are
the same at 1 atm as at 1.55 atm.
26.Given three solutions, each of which contains 1.0 g of solute dissolved in 100 mL of water, which of the following solutes will cause the solution to have the lowest freezing point?
D.All have the same freezing point.
27.What is the underlying process involved in dialysis?
Osmosis is due to a difference in solution concentrations.
28.The rate of osmosis:.
cannot be increased by any of the responses.
29.Which of the following pass through both osmotic and dialysis membranes?
Solvent molecules
30.What is the osmotic pressure of a 0.050 M solution of AlCl3 in water that is at 0.00°C? Consider AlCl3 to be a strong electrolyte.
osmotic pressure = i X concentration X R X T = 4 X 0.05 X 0.0821 X 273.15 = 4.49 atm = 3.4 × 103 torr
31.An isotonic salt solution is 0.90% (w/w) NaCl in water. How many grams of NaCl are contained in 1.00 kg of such a solution?
9.0
32.Which of the following is associated with cells in a hypertonic solution?
B.hemolysis
33.Given three solutions, each of which contains 1.0 g of solute dissolved in 100 mL of water, which of the following solutes will cause the solution to have the highest osmolarity?
D.None, they all have the same osmolarity.
34.Which of the following aqueous solutions will have the highest osmolarity?
D.All have the same osmolarity.
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