General Chemistry - Solutions & Intermolecular Forces (HW Help)

In summary, the conversation is about someone seeking help with their homework and asking for assistance with three questions. The questions involve identifying substances with hydrogen bonds, determining which substance has the highest boiling point, and predicting the changes in concentration and volume of a solution when more solid sucrose is added. The expert summarizer provides a possible answer for question one and explains the reasoning behind it. For question two, they point out that none of the answer choices have hydrogen bonding and suggest considering the strength of van der Waal forces to determine the substance with the highest boiling point. Finally, for question three, they suggest considering the definition of a supersaturated solution and encourage the person to think about the strength of van der Waal forces.
  • #1
katrina007
47
0
Hi,

I need some help with my homework. I have three questions which I'm not quite sure which answer it is, though I give it my best try. If anyone can help, it'll be much appreciated. Thanks in advance...

Question One:
Which of the following substances will have hydrogen bonds between molecules?
a) (CH3)3N
b) CH3-O-CH3
c) CH3CH2-OH
d) CH3CH2-F
e) HI

** (e) can't be the answer becuz it doesn't have any Hydrogen Bonds (N,O,F)
** (a) can't be the answer becuz the N atom is by itself. H atom is attached to C atom and therefore can't bond with the N atom. Same with letter (d)

I think the answer is c... Plez correct me if I'm wrong.

Question Two:
Which of the following should have the highest boiling point?
a) CF4
b) CCl4
c) CBr4
d) CI4
e) CH4

** I think the answer if (a) becuz of the Hydrogen Bonding forces being the strongest of all forces and therefore has highest boiling point. Plez tell me know if this is the right answer or not and explain why - (if possible)

Question Three
A solution of Sucrose (sugar) in water in in equilibrium with solid sucrose. If more solid sucrose is now added, with stirring,
a) the concentration of the solution will increase
b) the concentration of the solution will decrease
c) the concentration of the solution will remain same
d) the volume of solution will increase
e) a supersaturated solution will be produced.

** (c) can't be the answer becuz something is being added so it has to change - cannot remain same. I took a guess on this one and I think its letter (a). Again please tell me if I am wrong or correct. and explain if possible.


Answers to anyone or all of these questions will be greatly appreciated. Need this 3 homework probs. done by tomorrow. Again, thanks in advance.

Regards,
Katrina
 
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  • #2
Hello again,

Sorry to bump up this thread but please anyone out there that can help me with this 3 or anyone question(s)?
 
  • #3
katrina007 said:
Hi,

I need some help with my homework. I have three questions which I'm not quite sure which answer it is, though I give it my best try. If anyone can help, it'll be much appreciated. Thanks in advance...

Question One:
Which of the following substances will have hydrogen bonds between molecules?
a) (CH3)3N
b) CH3-O-CH3
c) CH3CH2-OH
d) CH3CH2-F
e) HI

** (e) can't be the answer becuz it doesn't have any Hydrogen Bonds (N,O,F)
** (a) can't be the answer becuz the N atom is by itself. H atom is attached to C atom and therefore can't bond with the N atom. Same with letter (d)

I think the answer is c... Plez correct me if I'm wrong.

Question Two:
Which of the following should have the highest boiling point?
a) CF4
b) CCl4
c) CBr4
d) CI4
e) CH4

** I think the answer if (a) becuz of the Hydrogen Bonding forces being the strongest of all forces and therefore has highest boiling point. Plez tell me know if this is the right answer or not and explain why - (if possible)

Question Three
A solution of Sucrose (sugar) in water in in equilibrium with solid sucrose. If more solid sucrose is now added, with stirring,
a) the concentration of the solution will increase
b) the concentration of the solution will decrease
c) the concentration of the solution will remain same
d) the volume of solution will increase
e) a supersaturated solution will be produced.

** (c) can't be the answer becuz something is being added so it has to change - cannot remain same. I took a guess on this one and I think its letter (a). Again please tell me if I am wrong or correct. and explain if possible.


Answers to anyone or all of these questions will be greatly appreciated. Need this 3 homework probs. done by tomorrow. Again, thanks in advance.

Regards,
Katrina

I agree that the best answer for #1 seems like C. Requirement for H bonding is that there's an electronegative atom (NOF) and a H bonded to an electronegative atom... so only answer choice C has an electronegative atom (O) and a hydrogen bonded to an electronegative atom (in the OH group)
 
  • #4
And for #3, if I understood the question correctly, looking at the definition of supersaturated solution may help:

http://www.chem.purdue.edu/gchelp/gloss/supersatsoln.html

supersaturated solution: a solution that contains more solute than it would if the dissolved solute were in equilibrium with the undissolved solute
 
  • #5
2: think molecular mass. 3: "equilibrium with solid sucrose" --- think, what color is George Washington's white horse?
 
  • #6
btw, for #2, in the given answer choices, there's no hydrogen bonding present.
 
  • #7
#2 the molecules are neither polar nnor possesses hydrogen bonding... van der waal forces exist as attractive forces between them...

what does the strength of van der waal forces depend on?? from this you will be able to determine the substance with higher bp...
 

1. What is the difference between a solution and a mixture?

A solution is a homogeneous mixture where the solute (substance being dissolved) is evenly distributed throughout the solvent (substance doing the dissolving). A mixture, on the other hand, can be either homogeneous (uniform composition throughout) or heterogeneous (non-uniform composition).

2. How does intermolecular forces affect the properties of a solution?

Intermolecular forces, such as hydrogen bonding and London dispersion forces, determine the strength of interactions between molecules in a solution. These forces can affect properties such as boiling and melting points, viscosity, and solubility.

3. What is the difference between a polar and nonpolar molecule?

A polar molecule has a positive and negative end due to an uneven distribution of electrons. Nonpolar molecules have an even distribution of electrons and do not have a positive or negative end. This difference in electron distribution affects the strength and type of intermolecular forces present in a substance.

4. How do you calculate the molarity of a solution?

Molarity (M) is calculated by dividing the moles of solute by the volume of the solution in liters. The formula is M = moles of solute / liters of solution. Make sure to convert the volume to liters before plugging it into the formula.

5. Can you provide an example of a solution with strong intermolecular forces?

An example of a solution with strong intermolecular forces is water (H2O). The polar nature of water molecules allows for strong hydrogen bonding, which results in a high boiling point and surface tension. These strong intermolecular forces also contribute to the unique properties of water, such as its ability to dissolve many substances.

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