Post a New Question

Chemistry..Please Help

posted by on .

1. The vapor pressure of dichloromethane, CH2Cl2, at 0C is 134mmHg. The normal boiling point of dichloromethane is 40C. Calculate its molar heat of vaporization

The answer is in kilojoules per mole.

I know i use the Clausius-Clapeyron equation but i don't know what to plug in.

____________________________________

2. Classify each property as associated with a liquid that has strong or weak intermolecular forces.

A. LOW BOILING POINT- weak
B. HIGH BOILING POINT- strong
C. LOW VAPOR PRESSURE
D. HIGH VAPOR PRESSURE
E. HIGH SURFACE TENSION
F. LOW SURFACE TENSION
G. HIGH Viscosity
H. LOW Viscosity

_____________________________________

3. The Society of Automotive Engineers has established an accepted numerical scale to measure the viscosity of motor oil. For example, SAE 40 motor oil has a higher viscosity than an SAE 10 oil.

Rank the following hydrocarbons by their expected viscosity.
Rank from most to least viscous.

a. CH3CH2CH2CH2CH2CH3
b. CH3CH2CH2CH2CH2CH2CH2CH3
c. CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
_______________________________________

  • Chemistry..Please Help - ,

    #1.
    Well, 0 degrees C the v.p. is 134. I would call those T1 and P1 (Be sure to convert T1 to Kelvin).
    The problem lists the normal boiling point as 40 degrees C. Convert that to Kelvin. The vapor pressure at the normal boiling point is 760 mm Hg. So those are T2 and P2. R is 8.314 J/mol. Delta H will have the units J/mol.

  • Chemistry..Please Help - ,

    2. Classify each property as associated with a liquid that has strong or weak intermolecular forces.

    A. LOW BOILING POINT- weak
    B. HIGH BOILING POINT- strong
    C. LOW VAPOR PRESSURE
    D. HIGH VAPOR PRESSURE
    E. HIGH SURFACE TENSION
    F. LOW SURFACE TENSION
    G. HIGH Viscosity
    H. LOW Viscosity
    A and B are ok. Think about them while answering the others. A liquid that has low vapor pressure has a high boiling point, does it not. And a liquid that has high vapor pressure has a low boiling point.
    Surface tension is how the surface molecules stick together. High surface tension means they stick together very well, low surface tension means they don't. Viscosity is how "thick" the material is. If it pours easily, it has low viscosity; if it pours with difficulty (like molasses) it has high viscosity. High viscosity means the molecules don't slide past each other easily so they must have high intermolecular forces.

  • Chemistry..Please Help - ,

    3. The Society of Automotive Engineers has established an accepted numerical scale to measure the viscosity of motor oil. For example, SAE 40 motor oil has a higher viscosity than an SAE 10 oil.

    Rank the following hydrocarbons by their expected viscosity.
    Rank from most to least viscous.

    a. CH3CH2CH2CH2CH2CH3
    b. CH3CH2CH2CH2CH2CH2CH2CH3
    c. CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
    I would think that the higher the molecular weight and the longer the chain, the easier it would be to get tangled up with each other Wouldn't that sound reasonable to you? Then 3 would have the highest viscosity and 1 would have the lowest. Check my thinking.

  • Chemistry..Please Help - ,

    Thank You got all the answers

  • Chemistry..Please Help - ,

    Rank from greatest to least surface tension.

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question