Chemistry 116: Exam #1 Study Guide
How many kilograms of CCl2F2 must be evaporated to freeze a tray of water at 0 C? The mass of the water is 525 g, the heat of fusion of ice is 6.01 kJ/mol, and the heat of vaporization of CCl2F2 is 17.4 kJ/mol.
-175 kg
Arrange the intermolecular forces in order of increasing strength.
1. LDF 2. Dipole-Dipole 3. Hydrogen Bonding 4. Ion-Dipole
The vapor pressure of ethanol is 115 torr at 34.9 C. If the Hvap of ethanol is 40.5 kj/mol calculate the temperature (in C) when the vapor pressure is 760 torr.
350 K
Liquid Ammonia (boiling point = -33.4 C) can be used as a refrigerant and heat transfer fluid. How much energy is needed to heat 25.0 g of NH3(l) from -65.0 C to -12.0 C?
39387.65 J
The fluorocarbon compound C2Cl3F3 has a normal boiling point of 47.6 C. The specific heats of C2Cl3F3(l) and C2Cl3F3(g) are 0.91 J/g-K and 0.67 J/g-K, respectively. The heat of vaporization for the compound is 27.49 kJ/mol. Calculate the heat required to convert 25 g of C2Cl3F3 from a liquid at 5.00 C to a gas at 82.00 C.
5213.07
Which of the following does not exhibit hydrogen bonding? A) CH2F2 B) CH3NH2 C) HF D) HOCH2CH2OH
A) CH2F2
Which of the following exhibits hydrogen bonding? A) CH3OH B) CH2O C) CH4 D) HCN
A) CH3OH
In liquid methanol, CH3OH which intermolecular forces are present? A) London, hydrogen bonding and dipole-dipole forces are present. B) Only dipole-dipole and ion-dipole forces are present. C) Only london and dipole-dipole forces are present. D) Only hydrogen bonding forces are present.
A) London, hydrogen bonding and dipole-dipole forces are present.
What quantity of heat is required to change 40.0 g of ice at melting point to liquid water? The heat of fusion of ice is 335 J/g. A. 13400 J B. 0.119 J C. 8.38 J D. 375 J
A. 13400 J
Hydrogen bonds form between molecules of A. H2O B. H2S C. H2Se D. H2Te
A. H2O
Which substance contains molecules that will not form hydrogen bonds? A. Hydrogen B. Hydrogen fluoride C. Water D. Ammonia
A. Hydrogen
Which phase change represents freezing? A. Liquid to solid B. Solid to liquid C. Liquid to gas D. Gas to liquid
A. Liquid to solid
Which phase change is sublimation? A. Solid to gas B. Liquid to gas C. Gas to liquid D. Solid to liquid
A. Solid to gas
Which is expected to have the largest dispersion forces? A) C2H6 B) C8H18 C) N2 D) CO2
B) C8H18
Which of the following compounds exhibits only dipole-dipole intermolecular interactions? A) N2 B) HBr C) CO2 D) H2O
B) HBr
Arrange the following in order of increasing boiling point. I) CH3CH2OH II) CH3CH2CH3 III) H3C-O-CH3 IV) CH3CH2NH2
B) II < III < IV < I
Which of the following exhibits ion-dipole forces? A) NaCl(s) B) NaCl(aq) C) Na(s) D) Cl2(g)
B) NaCl(aq)
A sample of water at 10.0 ° C absorbs 4410 J of heat energy. The temperature of the sample increases to 72.0 °C. What is the mass of the water? The specific heat of liquid water is 4.184 J/g°C. A. 14.7 g B. 17.0 g C. 256 g D. 297 g
B. 17.0 g
What amount of heat is required to convert 3.00 kg of water at its boiling point to steam? The heat of vaporization of water is 2.26 kJ/g. A. 6.78 kJ B. 6780 kJ C. 1330 kJ D. 1.33 kJ
B. 6780 kJ
Hydrogen bonds will form between molecules of compounds in which hydrogen is bonded to atoms of elements with A. High electronegativity and large atomic radius B. High electronegativity and small atomic radius C. Low electronegativity and large atomic radius D. Low electronegativity and small atomic radius
B. High electronegativity and small atomic radius
Which bond type is weakest? A. Polar covalent bond B. Nonpolar covalent bond C. Ionic bond D. Hydrogen bond
B. Nonpolar covalent bond
Which phase change represents melting? A. Liquid to solid B. Solid to liquid C. Liquid to gas D. Gas to liquid
B. Solid to liquid
Which has the smallest dipole-dipole forces? A) CH3F B) HCl C) N2 D) CO
C) N2
A sample of ice at 0° C absorbs 6030 J of heat energy. How much of the ice can melt? The heat of fusion of ice is 335 J/g. A. 6030 g B. 2.02 X 10 6 g C. 18.0 g D. 5700 g
C. 18.0 g
35. A 32.0 g sample of liquid water at 21.0 ° C absorbs 2276 J of heat energy. What will be the final temperature of the water? The specific heat of liquid water is 4.185 J/g °C. A. 4.0 0 C B. 17.0 0 C C. 38.0 0 C D. 58.0 0 C
C. 38.0 0 C
What quantity of heat must be removed from 20.0 g of liquid water at 0 °C to completely freeze the water? The heat of fusion of ice is 335 J/g. A. 315 J B. 16.8 J C. 6700 J D. 0.0597 J
C. 6700 J
A sample of water at 20. ° C contains A. Covalent bonds only B. Hydrogen bonds only C. Both, covalent and hydrogen bonds D. Neither, covalent nor hydrogen bonds
C. Both, covalent and hydrogen bonds
Hydrogen bonding will not occur in molecules that contain bonds between hydrogen and A. Fluorine B. Oxygen C. Bromine D. Nitrogen
C. Bromine
The amount of energy required to change one gram of a solid, at its freezing point, to a liquid is called its heat of A. Sublimation B. Vaporization C. Fusion D. Condensation
C. Fusion
Which phase change is evaporation? A. Solid to liquid B. Solid to gas C. Liquid to gas D. Liquid to solid
C. Liquid to gas
The freezing point of a substance is the temperature at which its
C. Solid phase is in equilibrium with its liquid phase
The melting point of a substance is the temperature at which its
C. Solid phase is in equilibrium with its liquid phase
The amount of energy required to change one gram of a liquid, at its boiling point, to a gas is called its heat of A. Fusion B. Freezing C. Vaporization D. Sublimation
C. Vaporization
Which of the following should have the lowest boiling point?
C5H12
Which of the following compounds exhibits hydrogen bonding? A) CH3Cl B) HI C) H3C-O-CH3 D) NH3
D) NH3
Which of the intermolecular forces is the most important contributor to the high surface tension shown by water? A) dipole-dipole forces B) dispersion (London) forces C) hydrogen bonding D) ion-dipole forces
D) ion-dipole forces
The magnitude of the heats of vaporization, fusion and sublimation of a substance reflect the A) density of the substance. B) magnitudes of the boiling and melting points of the substance. C) strength of the covalent bonds between atoms in each molecule of the substance. D) strength of the intermolecular forces of the substance.
D) strength of the intermolecular forces of the substance.
What quantity of heat is required to change the temperature of 30.0 g of water at 10.0 °C to 25.0 °C? The specific heat of liquid water is 4.184 J/g °C. A. 62.8 J B. 126 J C. 107 J D. 1880 J
D. 1880 J
An 18.0 g sample of liquid water at 42.0 ° C releases 979 J of heat energy. What is the final temperature of the water? The specific heat of liquid water is 4.184 J/g °C. A. 13.0 ° C B. 29.0 ° C C. 36.0 ° C D. 55.0 ° C
D. 55.0 ° C
What quantity of heat is required to convert 40.0 g of liquid water at its boiling point to steam? The heat of vaporization of water is 2.26 kJ/g. A. 17.7 kJ B. 0.0565 kJ C. 42.3 kJ D. 90.4 kJ
D. 90.4 kJ
Which phase change is condensation? A. Liquid to gas B. Solid to liquid C. Solid to gas D. Gas to liquid
D. Gas to liquid
The high boiling point of water is due to A. Polar covalent bonds B. Nonpolar covalent bonds C. Ionic bonds D. Hydrogen bonds
D. Hydrogen bonds
In which of the following substances in significant hydrogen bonding possible?
Hydrogen Peroxide (HOOH)
Which type of intermolecular attractive force operates between all molecules?
London Forces
Neon condenses due to
London dispersion forces
Which group of substances is arranged in order from the highest to the lowest melting point?
NaF > HF > H2
Examine the following phase diagram and identify the feature represented by point A.
Triple Point
In hydrogen iodide ___________ are the most important intermolecular forces.
dipole-dipole forces
Ammonia's unusually high melting point is the result of
hydrogen bonding
What are the changes in phase going from points A to B to C to D?
melting, vaporization, deposition
The stronger the intermolecular forces in a substance...
the higher the boiling point.
Which of the following properties does not increase with increasing intermolecular forces?
vapor pressure
