Test 1 – Chemistry Flashcard

 The Clausius-Clapeyron equation applies to
The liquid gas line of a pressure-temperature phase diagram.

Which of the following has the listed intermolecular interactions arranged from 

smallest interaction energy to largest interaction energy? 

Dipole-induced dipole < dipole-dipole 
The dominant intermolecular interaction between molecules of CO2 is
Dispersion

 

(Dynamic) equilibrium

A condition in which two opposing processes simultaneously 

occur at equal rates. 

 Vapor pressure
The equilibrium pressure of vapor above the surface of a liquid at a specified temperature.

 

Specific heat

The amount of heat needed to increase the temperature of 1 gram of material by 1°C. 
Provide the relationship between boiling point and strength of intermolecular interactions

The boiling point of a liquid increases as the strength of the intermolecular interactions 

between liquid phase molecules increases.

Describe the significance of a line in a pressure-temperature phase diagram

A line of a pressure-temperature phase diagram corresponds to temperatures and 

pressures at which the two phases on either side of the line are in equilibrium.

Molarity

Molarity(M) = 

 

mole solute/liter solution

Molality

molality (m) = 

 

mole solute/kilogram solvent

Parts Per Million

parts per million (ppm) =

 

mass of component/mass sample *106

The term fluid is used to describe which of the phases of matter?
The liquid and gas phases.
Describe the slope of the liquid/gas line and how this is related to the temperature dependence of vapor pressure. 

The slope of the liquid/gas line is always positive, thus indicating the vapor pressure of all 

liquids incresases as the temperature increases. 

Based on intermolecular interactions, arrange the following from lowest to highest 

vapor pressure (vp). 

HF,  CH4,  Br2,  PH3,  HO-CH2-CH2-OH (ethylene glycol)

Low vp                                   High  vp 

HO-CH2-CH2-OH HF  PH3 Br2 CH4

Vapor pressure increases as the strength of the intermolecular interaction between liquid phase molecules 

decreases. 

HF     Hydrogen bond (strong dipole-dipole) interaction 

HO-CH2-CH2-OH     Hydrogen bond 

Each HF molecule has one hydrogen bonding site, while each  HO-CH2-CH2-OH molecule has two sites, 

therefore the hydrogen bond interaction of HO-CH2-CH2-OH is stronger than HF. 

CH4     Dispersion interaction 

Br2     Dispersion interaction 

Based on mass, the Br2 dispersion interaction is stronger than the CH4 dispersion interaction. 

PH3     dipole-dipole interaction (there is a lone pair of electrons on the central atom) 

Identify the dominant intermolecular interaction associated with each of the 

following pure substances.

BF3  Dispersion interaction.  BF3 is a nonpolar molecule (all things bonded to the 

central atom are identical and there are no lone pairs on the central atom). 

 CO  Dipole-dipole interaction.  CO is a polar molecule. 

  

H2O  Hydrogen bond interaction.

NaCl  Ion–ion interaction.  NaCl is an ionic compound. 

At 34.1°C the vapor pressure of water is 40.1 torr.  What is the vapor pressure of 

water at 85.5°C? ΔHvap of water is 40.7 kJ/mol. 

 

P2= inv ln(5.976862157)= 394.2 torr

 

Determine the amount of heat needed to convert 25.0 grams of liquid benzene 

(C6H6) at 22°C to gas phase benzene at 80.1°C.  The boiling point of benzene is 80.1°C,                                 

c benzene liquid = 1.74 J/g °,   ΔHvap 

Heat require = step 1 + step 2 = 2527.35 J + 10850 J = 13377 J = 13.377 kJ 

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