Question 1

Calculate the freezing point when 25.0 g of ethanol, C2H5OH, is dissolved in 500.0 g of H2O.

Accepted Answer

Freezing point = -2.02°C

Question 2

What is the molar mass of glucose if 22.5 g gives a freezing point of -0.930°C when dissolved in 250.0 g of water? If the empirical formula is CH2O, what is the molecular formula?

Accepted Answer

180. g/mol; C₆H₁₂O₆

Question 3

Which of the following chemical or physical changes is an endothermic process?

Accepted Answer

A)  the mixing of sulfuric acid and water 
B)  the freezing of water 
C)  the evaporation of water 
D)  the combustion of gasoline 
E)  none of these 
A)  the mixing of sulfuric acid and water 
B)  the freezing of water 
C)  the evaporation of water 
D)  the combustion of gasoline 
E)  none of these C

Question 4

When 0.800 g of NH4NO3 was added to 150.0 g of water in a styrofoam cup, the temperature dropped by 0.413°C. The heat capacity of H2O is 4.18 J/g°C. Assume the specific heat of the solution equals that of pure H2O and that the calorimeter neither absorbs nor leaks heat. What is the molar heat of solution of solid NH4NO3?

Accepted Answer

A)  +260. J/mol 
B)  -2.60 kJ/mol 
C)  +2.60 kJ/mol 
D)  +26.0 kJ/mol 
E)  none of these 
A)  +260. J/mol 
B)  -2.60 kJ/mol 
C)  +2.60 kJ/mol 
D)  +26.0 kJ/mol 
E)  none of these

Question 5

An aqueous solution of a compound with a molar mass of 34.02 g/mol is 24.5% by mass and has a density of 1.09 g/cm3. What is the molarity of the solution?

Accepted Answer

A)  7.85 M 
B)  7.20 M 
C)  1.31 M 
D)  0.000785 M 
E)  6.61 M 
A)  7.85 M 
B)  7.20 M 
C)  1.31 M 
D)  0.000785 M 
E)  6.61 M

Question 6

An aqueous solution is 1.00% NaCl by mass. Its density is 1.071 g/mL at 25°C. The observed osmotic pressure of this solution is 7.83 atm at 25°C.
A. What fraction of the moles of NaCl in this solution are ion pairs?
B. Calculate the freezing point that would be observed for this solution; Kf for H2O = 1.86°C kg/mol.

Accepted Answer

Question 7

When 100.0 g of a compound is dissolved in 1500. g of water, the freezing point of the solution is lowered to -1.35°C. Determine the molar mass of the compound.

Accepted Answer

The answer of When 100.0 g of a compound is...

Question 8

A solution is composed of two liquids, A and B. For every 2.54 mol of A, there are 6.10 mol of B. What is the mole fraction of liquid A in the solution?

Accepted Answer

A)  0.706 
B)  0.584 
C)  0.416 
D)  0.294 
E)  0.713 
A)  0.706 
B)  0.584 
C)  0.416 
D)  0.294 
E)  0.713

Question 9

The osmotic pressure of a 0.0100 M solution of NaCl in water at 25°C is found to be different from 372 torr because

Accepted Answer

A)  osmotic pressures are hard to measure. 
B)  Na+ and Cl- ions are strongly hydrated. 
C)  NaCl does not dissociate in water. 
D)  Na+ and Cl- ions can form ion pairs. 
E)  none of these 
A)  osmotic pressures are hard to measure. 
B)  Na+ and Cl- ions are strongly hydrated. 
C)  NaCl does not dissociate in water. 
D)  Na+ and Cl- ions can form ion pairs. 
E)  none of these

Question 10

Which of the following statements is(are) true?

Accepted Answer

A)  The rate of dissolution of a solid in a liquid always increases with increasing temperature. 
B)  The solubility of a solid in a liquid always increases with increasing temperature. 
C)  According to Henry's law, the amount of gas dissolved in a solution is directly proportional to the pressure of the gas above the liquid. 
D)  Two of these statements are true. 
E)  All of these statements are true. 
A)  The rate of dissolution of a solid in a liquid always increases with increasing temperature. 
B)  The solubility of a solid in a liquid always increases with increasing temperature. 
C)  According to Henry's law, the amount of gas dissolved in a solution is directly proportional to the pressure of the gas above the liquid. 
D)  Two of these statements are true. 
E)  All of these statements are true.

Question 11

The scattering of light by particles is called the _____.

Accepted Answer

A)  ​Tyndall effect 
B)  ​Accordion effect 
C)  ​Chorus effect 
D)  ​Flynn effect 
E)  ​Mullins effect 
A)  ​Tyndall effect 
B)  ​Accordion effect 
C)  ​Chorus effect 
D)  ​Flynn effect 
E)  ​Mullins effect

Question 12

The solubility of O2 in water is 0.590 g/L at an oxygen pressure of 15 atm. What is the Henry's law constant for O2 (in units of L atm/mol)?

Accepted Answer

A)  3.93 × 10-3 
B)  1.23 × 10-3 
C)  8.14 × 102 
D)  1.26 
E)  None of the above is within 5% of the correct answer. 
A)  3.93 × 10-3 
B)  1.23 × 10-3 
C)  8.14 × 102 
D)  1.26 
E)  None of the above is within 5% of the correct answer.

Question 13

The freezing point (Tf) for t-butanol is 25.50°C, and Kf is 9.1°C/m. Usually t-butanol absorbs water on exposure to the air. If the freezing point of a 13.7-g sample of t-butanol is measured as 24.81°C, how many grams of water are present in the sample?

Accepted Answer

A)  8.3 g 
B)  0.019 g 
C)  0.18 g 
D)  0.025 g 
E)  0.91 g 
A)  8.3 g 
B)  0.019 g 
C)  0.18 g 
D)  0.025 g 
E)  0.91 g

Question 14

At a given temperature, you have a mixture of benzene (Pvap = 745 torr) and toluene (Pvap = 290 torr). The mole fraction of benzene in the solution is 0.590. Assuming ideal behavior, calculate the mole fraction of toluene in the vapor above the solution.

Accepted Answer

A)  0.778 
B)  0.641 
C)  0.355 
D)  0.213 
E)  0.590 
A)  0.778 
B)  0.641 
C)  0.355 
D)  0.213 
E)  0.590

Question 15

Consider a sample solution with osmotic pressure of 9.45 atm at 42°C. Determine the concentration of sodium chloride in water needed to produce an aqueous solution isotonic with the sample solution.

Accepted Answer

A)  ​0.366 M 
B)  ​1.181 M 
C)  ​0.183 M 
D)  ​1.113 M 
E)  ​0.215 M 
A)  ​0.366 M 
B)  ​1.181 M 
C)  ​0.183 M 
D)  ​1.113 M 
E)  ​0.215 M

Question 16

Which of the following statements is/are true of the factors affecting solubility of a material?
1) Nonpolar materials are hydrophobic and polar materials are hydrophilic.
2) Pressure has little effect on the solubility of solids or liquids but it increases the solubility of a gas.
3) Solubility of all the solids increases with increasing temperature.

Accepted Answer

A)  ​1 only 
B)  ​3 only 
C)  ​1 and 2 
D)  ​1 and 3 
E)  ​2 and 3 
A)  ​1 only 
B)  ​3 only 
C)  ​1 and 2 
D)  ​1 and 3 
E)  ​2 and 3

Question 17

Predict the deviation from Raoult's law when two liquids are mixed and the heat of the solution is large and the reaction exothermic.

Accepted Answer

A)  positive deviation 
B)  relatively ideal (small or zero deviation) 
C)  negative deviation 
A)  positive deviation 
B)  relatively ideal (small or zero deviation) 
C)  negative deviation

Question 18

A solution containing 100.0 g of NaCl per liter has a density of 1.095 g/mL. What is the molality of the solution?

Accepted Answer

A)  0.5873 m 
B)  1.711 m 
C)  1.720 m 
D)  0.5844 m 
E)  none of these 
A)  0.5873 m 
B)  1.711 m 
C)  1.720 m 
D)  0.5844 m 
E)  none of these

Question 19

Pentane (C5H12) and hexane (C6H14) form an ideal solution. The vapor pressures of pentane and hexane at 25° C are 511 torr and 150 torr, respectively. The mole fraction of hexane in a pentane-hexane solution is 0.50. Calculate the mole fraction of pentane in the vapor that is in equilibrium at 25°C with this solution.

Accepted Answer

A)  0.23 
B)  0.77 
C)  0.89 
D)  0.50 
E)  none of these 
A)  0.23 
B)  0.77 
C)  0.89 
D)  0.50 
E)  none of these

Question 20

A 48.4-g sample of glucose (a nondissociated, nonvolatile solute with the formula C6H12O6) is dissolved in 151.2 g of water. What is the vapor pressure of this solution at 100°C?

Accepted Answer

A)  736 torr 
B)  576 torr 
C)  23.6 torr 
D)  760 torr 
E)  184 torr 
A)  736 torr 
B)  576 torr 
C)  23.6 torr 
D)  760 torr 
E)  184 torr

Calculate the freezing point when 25.0 g of ethanol, C₂H₅OH, is dissolved in 500.0 g of H₂O.

What is the molar mass of glucose if 22.5 g gives a freezing point of -0.930°C when dissolved in 250.0 g of water? If the empirical formula is CH₂O, what is the molecular formula?

Which of the following chemical or physical changes is an endothermic process?

An aqueous solution of a compound with a molar mass of 34.02 g/mol is 24.5% by mass and has a density of 1.09 g/cm³. What is the molarity of the solution?

When 100.0 g of a compound is dissolved in 1500. g of water, the freezing point of the solution is lowered to -1.35°C. Determine the molar mass of the compound.

A solution is composed of two liquids, A and B. For every 2.54 mol of A, there are 6.10 mol of B. What is the mole fraction of liquid A in the solution?

The osmotic pressure of a 0.0100 M solution of NaCl in water at 25°C is found to be different from 372 torr because

Which of the following statements is(are) true?

The scattering of light by particles is called the _____.

The solubility of O₂ in water is 0.590 g/L at an oxygen pressure of 15 atm. What is the Henry's law constant for O₂ (in units of L atm/mol)?

The freezing point (T_f) for t-butanol is 25.50°C, and K_f is 9.1°C/m. Usually t-butanol absorbs water on exposure to the air. If the freezing point of a 13.7-g sample of t-butanol is measured as 24.81°C, how many grams of water are present in the sample?

At a given temperature, you have a mixture of benzene (P_vap = 745 torr) and toluene (P_vap = 290 torr). The mole fraction of benzene in the solution is 0.590. Assuming ideal behavior, calculate the mole fraction of toluene in the vapor above the solution.

Consider a sample solution with osmotic pressure of 9.45 atm at 42°C. Determine the concentration of sodium chloride in water needed to produce an aqueous solution isotonic with the sample solution.

Predict the deviation from Raoult's law when two liquids are mixed and the heat of the solution is large and the reaction exothermic.

A solution containing 100.0 g of NaCl per liter has a density of 1.095 g/mL. What is the molality of the solution?

A 48.4-g sample of glucose (a nondissociated, nonvolatile solute with the formula C₆H₁₂O₆) is dissolved in 151.2 g of water. What is the vapor pressure of this solution at 100°C?

Atoms, Molecules, and Ions

Stoichiometry

Types of Chemical Reactions and Solution Stoichiometry

Gases

Chemical Equilibrium

Acids and Bases

Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

Spontaneity, Entropy, and Free Energy

Electrochemistry

Quantum Mechanics and Atomic Theory

Bonding: General Concepts

Covalent Bonding: Orbitals

Chemical Kinetics

Liquids and Solids

The Representative Elements

Transition Metals and Coordination Chemistry

The Nucleus: a Chemists View

Organic and Biochemical Molecules

Filters

Exam 17: Properties of Solutions

Calculate the freezing point when 25.0 g of ethanol, C2H5OH, is dissolved in 500.0 g of H2O.

What is the molar mass of glucose if 22.5 g gives a freezing point of -0.930°C when dissolved in 250.0 g of water? If the empirical formula is CH2O, what is the molecular formula?

Which of the following chemical or physical changes is an endothermic process?

An aqueous solution of a compound with a molar mass of 34.02 g/mol is 24.5% by mass and has a density of 1.09 g/cm3. What is the molarity of the solution?

When 100.0 g of a compound is dissolved in 1500. g of water, the freezing point of the solution is lowered to -1.35°C. Determine the molar mass of the compound.

A solution is composed of two liquids, A and B. For every 2.54 mol of A, there are 6.10 mol of B. What is the mole fraction of liquid A in the solution?

The osmotic pressure of a 0.0100 M solution of NaCl in water at 25°C is found to be different from 372 torr because

Which of the following statements is(are) true?

The scattering of light by particles is called the _____.

The solubility of O2 in water is 0.590 g/L at an oxygen pressure of 15 atm. What is the Henry's law constant for O2 (in units of L atm/mol)?

The freezing point (Tf) for t-butanol is 25.50°C, and Kf is 9.1°C/m. Usually t-butanol absorbs water on exposure to the air. If the freezing point of a 13.7-g sample of t-butanol is measured as 24.81°C, how many grams of water are present in the sample?

At a given temperature, you have a mixture of benzene (Pvap = 745 torr) and toluene (Pvap = 290 torr). The mole fraction of benzene in the solution is 0.590. Assuming ideal behavior, calculate the mole fraction of toluene in the vapor above the solution.

Consider a sample solution with osmotic pressure of 9.45 atm at 42°C. Determine the concentration of sodium chloride in water needed to produce an aqueous solution isotonic with the sample solution.

Predict the deviation from Raoult's law when two liquids are mixed and the heat of the solution is large and the reaction exothermic.

A solution containing 100.0 g of NaCl per liter has a density of 1.095 g/mL. What is the molality of the solution?

A 48.4-g sample of glucose (a nondissociated, nonvolatile solute with the formula C6H12O6) is dissolved in 151.2 g of water. What is the vapor pressure of this solution at 100°C?

Atoms, Molecules, and Ions

Stoichiometry

Types of Chemical Reactions and Solution Stoichiometry

Gases

Chemical Equilibrium

Acids and Bases

Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

Spontaneity, Entropy, and Free Energy

Electrochemistry

Quantum Mechanics and Atomic Theory

Bonding: General Concepts

Covalent Bonding: Orbitals

Chemical Kinetics

Liquids and Solids

The Representative Elements

Transition Metals and Coordination Chemistry

The Nucleus: a Chemists View

Organic and Biochemical Molecules

Filters

Calculate the freezing point when 25.0 g of ethanol, C₂H₅OH, is dissolved in 500.0 g of H₂O.

What is the molar mass of glucose if 22.5 g gives a freezing point of -0.930°C when dissolved in 250.0 g of water? If the empirical formula is CH₂O, what is the molecular formula?

An aqueous solution of a compound with a molar mass of 34.02 g/mol is 24.5% by mass and has a density of 1.09 g/cm³. What is the molarity of the solution?

The solubility of O₂ in water is 0.590 g/L at an oxygen pressure of 15 atm. What is the Henry's law constant for O₂ (in units of L atm/mol)?

The freezing point (T_f) for t-butanol is 25.50°C, and K_f is 9.1°C/m. Usually t-butanol absorbs water on exposure to the air. If the freezing point of a 13.7-g sample of t-butanol is measured as 24.81°C, how many grams of water are present in the sample?

At a given temperature, you have a mixture of benzene (P_vap = 745 torr) and toluene (P_vap = 290 torr). The mole fraction of benzene in the solution is 0.590. Assuming ideal behavior, calculate the mole fraction of toluene in the vapor above the solution.

A 48.4-g sample of glucose (a nondissociated, nonvolatile solute with the formula C₆H₁₂O₆) is dissolved in 151.2 g of water. What is the vapor pressure of this solution at 100°C?