chem midterm 2

The reaction that represents the standard enthalpy of formation for sucrose (C12H22O11) is: A) 12 C(graphite) + 11 H2(g) + 11/2 O2(g) --> C12H22O11(s) B) C12H22O11(s) --> 12 C(graphite) + 11 H2(g) + 11/2 O2(g) C) 12 C(diamond) + 11 H2(g) + 11/2 O2(g) --> C12H22O11(s) D) C12H22O11(s) + 12 O2 --> 12 CO2(g) + 11 H2O(g) E) 24 C(diamond) + 22 H2(g) + 11 O2(g) --> 2 C12H22O11(s)

A) 12 C(graphite) + 11 H2(g) + 11/2 O2(g) --> C12H22O11(s)

The number of atoms in a body-centered cubic unit cell is A) 2 B) 3 C) 8 D) 1 E) 4

A) 2

assuming 100% dissociation, which of the following compounds is listed incorrectly with its van't Hoff factor i? A) Al2(SO4)3, i = 4 B) Mg(NO3)2, i = 3 C) Na2SO4, i = 3 D) NH4NO3, i = 2 E) Sucrose, i = 1

A) Al2(SO4)3, i = 4

For which of the following species are the dispersion forces strongest? A) C8H18 B) C6H14 C) C7H16 D) C4H10 E) C5H12

A) C8H18

Which of the following phase changes is exothermic? A) Condensation B) Vaporization C) Sublimation D) Melting

A) Condensation

phase change from the gas phase directly to the solid phase is called: A) Deposition B) Sublimation C) Melting D) Condensation E) Freezing

A) Deposition

Which of the following properties indicates the presence of strong intermolecular forces in a liquid? A) a low vapor pressure B) a low boiling point C) a low critical temperature D) a low heat of vaporization E) None of the above

A) a low vapor pressure

Heat is A) a measure of thermal energy transferred between two bodies at different temperature .B) a measure of thermal energy. C) a measure of temperature. D) a measure of the change in temperature

A) a measure of thermal energy transferred between two bodies at different temperature

An endothermic reaction causes the surroundings to A) decrease in temperature .B) condense. C) warm up. D) release CO2. E) become acidic.

A) decrease in temperature

the solubility of gases in water usually increases with' A) decreasing temperature and increasing pressure B) increasing temperature only C) increasing temperature and decreasing pressure D) increasing pressure and increasing temperature E) decreasing temperature and decreasing pressure

A) decreasing temperature and increasing pressure

Which two properties are more typical of molecular compounds than of ionic compounds? 1. They are gases or liquids at room temperature. 2. They have high melting points. 3. Solids do not conduct electricity, but liquids do. 4. Atoms share electrons. A) 2 and 3 B) 1 and 4 C) 2 and 4 D) 3 and 4E ) 1 and 3

B) 1 and 4

arrange the following in order of increasing boiling point: RbCl, CH3Cl, CH3OH, CH4 .A) RbCl < CH3Cl < CH3OH < CH4 B) CH4 < CH3Cl < CH3OH < RbCl C) CH3OH < CH4 < CH3Cl < RbCl D) CH3OH < CH3Cl < RbCl < CH4 E) CH4 < CH3OH < CH3Cl < RbCl

B) CH4 < CH3Cl < CH3OH < RbCl

Which of the following substances is expected to have the highest molar heat of vaporization (Hvap)? A) NH3 B) H2O C) C6H6 D) He E) Ar

B) H2O

Which of the following has a H°f = 0 kJ/mol? A) Cl-(aq) B) I2(s) C) O3(g) D) CO2(g) E) NH3(aq)

B) I2(s)

Which one of the following substances should exhibit hydrogen bonding in the liquid state? A) CH4 B) NH3 C) PH3 D) H2 E) H2S

B) NH3

Which of the following would be expected to have the highest vapor pressure at room temperature? A) water, bp = 100°C B) acetone, bp = 56°C C) methanol, bp = 65°C D) ethanol, bp = 78°C

B) acetone, bp = 56°C

An exothermic reaction causes the surroundings to A) expand. B) increase in temperature C) decrease in temperature. D) release CO2. E) become acidic

B) increase in temperature

Arrange the following aqueous solutions in order of increasing boiling points: 0.300m C6H12O6,0.110m K2CO3, and 0.050m Al(ClO4)3 A) K2CO3 < C6H12O6 < Al(ClO4)3 B) K2CO3 < Al(ClO4)3 < C6H12O6 C) Al(ClO4)3 < C6H12O6 < K2CO3 D) C6H12O6 < Al(ClO4)3 < K2CO3 E) C6H12O6 < K2CO3 < Al(ClO4)

C) Al(ClO4)3 < C6H12O6 < K2CO3

Which of the following processes is exothermic? A) 6 H2O(g) + 4 CO2(g) -->2 C2H6(g) + 7 O2(g) B) CO2(s) -> CO2(g) C) CH4(g) + 2 O2(g) --> CO2(g) + 2 H2O(l) D) CO2(g) + 2 H2O(l) --> CH4(g) + 2 O2(g) E) H2O(l) --> H2O(g

C) Al(ClO4)3 < C6H12O6 < K2CO3

Three separate 3.5g blocks of Al, Cu, and Fe at 25 °C each absorb 0.505 kJ of heat. Which block reaches the highest temperature? The specific heats of Al, Cu, and Fe are 0.900 J/g·°C, 0.385J/g·°C, and 0.444 J/g·°C, respectively. A) Fe and Cu B) Al and Cu C) Cu D) Al E) Fe

C) Cu

arrange the following substances in order of increasing boiling point: CH3OH, He, CH3Cl, and N2 A) He < N2 < CH3OH < CH3Cl B) N2 < He < CH3OH < CH3Cl C) He < N2 < CH3Cl < CH3OH D) CH3Cl < He < N2 < CH3OH E) CH3OH < He < CH3Cl < N2

C) He < N2 < CH3Cl < CH3OH

Which one of the following substances is expected to have the highest boiling point? A) F2 B) Br2 C) I2 D) Cl2

C) I2

Arrange the following aqueous solutions in order of increasing boiling points: 0.050m Mg(NO3)2; 0.100m ethanol;0.090m NaCl. A) NaCl < ethanol < Mg(NO3)2 B) Mg(NO3)2 < NaCl < ethanol C) ethanol < Mg(NO3)2 < NaCl D) Mg(NO3)2 < ethanol < NaCl E) ethanol < NaCl < Mg(NO3)2

C) ethanol < Mg(NO3)2 < NaCl

During osmosis A) gases diffuse through a membrane into a solution and build up pressure. B) pure solvent and a solution both diffuse at the same time through a membrane. C) pure solvent diffuses through a membrane but solutes do not. D) pure solutes diffuse through a membrane but solvent does not.

C) pure solvent diffuses through a membrane but solutes do not.

Which one of the following substances is expected to have the lowest melting point? A) CsI B) RbI C) NaI D) BrI E) LiI

D) BrI

Which one of the following substances is expected to have the highest boiling point? A) HI B) HBr C) HCl D) HF

D) HF

Which of the following has a H°f = 0 kJ/mol? A) NH3(aq) B) Cl-(aq) C) CO2(g) D) I2(s) E) O3(g)

D) I2(s)

Which one of the following substances should exhibit hydrogen bonding in the liquid state? A) H2 B) H2S C) CH4 D) NH3 E) PH3

D) NH3

Each of the following substances is a liquid at -50°C. Place these liquids in order of increasing vaporpressure: dimethyl ether (CH3OCH3), propane (C3H8), and ethanol (CH3CH2OH). A) propane < ethanol < dimethyl ether B) ethanol < propane < dimethyl ether C) dimethyl ether < ethanol < propane D) ethanol < dimethyl ether < propane E) propane < dimethyl ether < ethano

D) ethanol < dimethyl ether < propane

A liquid boils when its A) temperature is greater than room temperature. B) temperature is equal to 273 K (standard temperature). C) vapor pressure is exactly 1 atmosphere. D) vapor pressure is equal to, or greater than, the external pressure pushing on it

D) vapor pressure is equal to, or greater than, the external pressure pushing on it

According to Raoult's law, which statement is false? A) The vapor pressure of a solvent over a solution is less than that of pure solvent. B) The greater the pressure of a gas over a solution the greater its solubility. C) The solubility of a gas increases as the temperature decreases. D) Ionic solutes dissociate in solution causing an enhancement of all colligative properties. E) The vapor pressure of a solvent over a solution decreases as its mole fraction increases

E) The vapor pressure of a solvent over a solution decreases as its mole fraction increases

Suppose a 50.0 g block of silver (specific heat = 0.2350 J/g·°C) at 100°C is placed in contact with a50.0 g block of iron (specific heat = 0.4494 J/g·°C) at 0°C, and the two blocks are insulated from therest of the universe. The final temperature of the two blocks A) is unrelated to the composition of the blocks. B) will be exactly 50°C. C) will be higher than 50°C. D) cannot be predicted .E) will be lower than 50°C

E) will be lower than 50°C