4 super tough chemistry questions:

1.) Water has a considerably higher boiling point and lower vapor pressure than other molecules of similar or larger molar mass. For example, dinitrogen (N2), methane (CH4), etc. all have lower boiling points and higher vapor pressures than water at the same temperature. How might this be explained?

2.) If the intermolecular forces between molecules of a substance were very small, what effect would you expect this to have on the boiling point and vapor pressure of the substance? What properties would you look for in a molecule in order to have a low boiling point and high vapor pressure? Should the atoms of the molecules be large or small? Why might this matter? Give two or three examples of molecules where you might expect the intermolecular forces to be very small.

3.) Why would contact with steam at 100 C produce a more severe burn than contact with liquid water at the same temperature?

4.) Orange growers often spray water on their trees to protect the fruit in freezing weather. Explain how the energy of the water --> ice phase transition could provide protection from freezing weather.

  1. 👍 0
  2. 👎 0
  3. 👁 178
asked by .
  1. We will be happy to critique your thinking.

  2. 1, 2, and 3 I have no answers. I've been staring at my monitor for 47 minutes now and I'm not coming up with any answer.

    As for no. 4, I think it's because water protects/shields the fruit.

    Actually, I think my answer for no. 3 is because steam has heat which is why it will produce a more severe burn than just plain water.

    1. 👍 0
    2. 👎 0
    posted by .
  3. #4. The "protection" afforded by the ice is not so much from a shielding effect (I think a common misconception) as it is from the heat. Look at it this way,
    ice + heat ==> liquid water.
    So melting ice is an endothermic reaction; that is, you put heat in to melt the ice. So the reverse (turn the arrow around) must be an exothermic reaction; that is, heat must be given off.

    The steam question. Burns by steam (at 100 C) are worse than burns by water (at 100 C) because, in addition to the burns of the water, there is an excess of 2260 joules for every grams of steam that turns into water when it condenses. So that much more energy is emitted.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    Which of the following statements about boiling points are true? A. The boiling point of 0.1 m NaF(aq) is lower than the boiling point of 0.1 m methanol(aq). B. The boiling point of a 0.5 m aqueous solution of LiOH is the same as

    asked by Anonymous on April 18, 2013
  2. Chemistry

    Explain what happens when you add sodium chloride to boiling water. I know that when sodium chloride is added to water, the boiling point of water increases. What happens when it is added to already boiling water? I know it

    asked by Mercedes on January 31, 2007
  3. chemistry

    If a solution has a lot of particles, is it going to have a low or high boiling point? For instance, would NaCl have a higher or lower boiling point than C12H22O11, based on the amount of particles it has (NaCl has more than

    asked by Grace on April 19, 2007
  4. Chemistry

    Explain the following observations using chem principles: When table salt and sugar are dissolved in water, it is observed that: 1. Both solutions have a higher boiling point than pure water. 2. the boiling point of .1 M NaCl

    asked by Anonymous on January 17, 2008
  5. Chemistry

    Which of the following statements about boiling points are false: A. the boiling point of 0.1 m KF(aq) is lower than the boiling point of 0.1 m ethanol(aq) B. the boiling point of a 0.5 m aqueous solution of NaOH is the same as

    asked by Timothy on September 8, 2010
  6. chemistry

    when pressure decreases what happens with the boiling point, it decreases, increases or stays the same? I read the book (the example used is water) were it says that if vapor pressure is less than the pressure pushing down on the

    asked by Fabiola on May 23, 2007
  7. Chemistry

    Which of the following statements is (are) true? A. The vapor pressure of CO2 is lower than the vapor pressure of water. B. Sea water has a lower vapor pressure than distilled water. C. The vapor pressure of 1 m NaCl is higher

    asked by kendra on August 30, 2010
  8. heat

    At what point will liquid alcohol change to vapor? Boiling Melting Fusing Freezing The boiling point is the point above which the liquid state does not exist. Evaporation can occur from the liquid state at lower temperatures as

    asked by alf on August 3, 2005
  9. Chemistry

    Which substance ( HBr or HF ) has the higher boiling point? Its HF but chose one of the most appropriate reason. 1. Both substances are nonpolar but the higher boiling includes hydrogen bonding 2. Both substances are nonpolar but

    asked by ss01 on October 12, 2013
  10. AP Chemistry help!!!!!

    How does the boiling point of ethane (CH3CH3) compare with that of ethanol (CH3CH2OH)? 1. The boiling point of ethane is higher because it has stronger London dispersion forces. 2. The boiling point of ethane is higher because it

    asked by Stephen on August 18, 2016

More Similar Questions