Determining the positive and negative poles of a molecule

In summary, the molecule CHCl3 has a tetrahedral shape and is polar due to the differences in electronegativity between carbon, hydrogen, and chlorine. The chlorine side of the molecule has a negative charge while the hydrogen side has a positive charge.
  • #1
Specter

Homework Statement


For the molecule CHCl3,

a) Draw the electron dot diagram and structural formula
b) predict the shape
c) predict whether it is polar or non-polar, and justify your prediction. Indicate the positive and negative poles.

Homework Equations


none

The Attempt at a Solution


[/B]
Are there any websites or programs that will allow me to create lewis dot diagrams, structural formulas, and all of that fun stuff on a computer? As of right now I am doing it on paper and uploading it for my teacher.

a) My electron dot diagram is correct, I searched it up online. The structural formula is Carbon as the central atom with Hydrogen above it, and three Cl atoms surrounding it. They are all single bonds.

b) The shape of CHCl3 is tetrahedral because the central carbon atom is surrounded by 4 bonding pairs, and 0 lone pairs.

c) This is probably incorrect but I gave it a shot.

C = 2.5 EN
H = 2.2 EN
Cl = 3.1 EN

The hydrogen dipole arrow is pointed in the direction of carbon because carbon is more electronegative than hydrogen. The chlorine bond dipole arrows point in the direction of chlorine because it is more electronegative than carbon and hydrogen. The dipoles are not identical in strength, they are not arranged symmetrically, and they do not cancel each other out therefore the molecule is polar.

I'm not sure how to figure out which poles are positive and which are negative. Would Hydrogen be the negative pole, and Chlorine be the positive pole? Hydrogen is the least electronegative of the 3 atoms, and chlorine is the most electronegative of the 3. What would carbon be?

Any help is appreciated, thanks!
 
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  • #2
Do you know geometry of the methane molecule?

In general the most electronegative element draws most electrons to itself. What kind of charge - positive or negative - will it have?
 
  • #3
Borek said:
Do you know geometry of the methane molecule?

In general the most electronegative element draws most electrons to itself. What kind of charge - positive or negative - will it have?

By geometry, do you mean molecular shape? I just learned that in this lesson. VSEPR says that methane would be a tetrahedral shape.

If the most electronegative element draws electrons to itself (chlorine in my question) wouldn't it have a positive charge? I'm still confused by this.
 
  • #4
Specter said:
methane would be a tetrahedral shape.

Right. If three hydrogen atoms are replaced they have to on one side of the carbon - so we can expect the molecule to have a a dipole moment.

Specter said:
If the most electronegative element draws electrons to itself (chlorine in my question) wouldn't it have a positive charge? I'm still confused by this.

It draws electrons, so it has an excess of electrons. What is the electron charge?
 
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  • #5
Borek said:
Right. If three hydrogen atoms are replaced they have to on one side of the carbon - so we can expect the molecule to have a a dipole moment.
It draws electrons, so it has an excess of electrons. What is the electron charge?
Ahh okay. So the chlorine side would be negative and the hydrogen side would be positive.
 
  • #6
Yep.
 
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  • #7
Borek said:
Yep.
Thanks for the help!
 

Related to Determining the positive and negative poles of a molecule

1. What is the purpose of determining the positive and negative poles of a molecule?

The purpose of determining the positive and negative poles of a molecule is to understand its polarity. This information is important in predicting the molecule's behavior and interactions with other molecules.

2. How are the positive and negative poles of a molecule determined?

The positive and negative poles of a molecule are determined by looking at its molecular structure and the distribution of its electrons. If there is an uneven distribution of electrons, the molecule will have a positive and negative pole.

3. Why is it important to know the positive and negative poles of a molecule?

Knowing the positive and negative poles of a molecule is important because it affects the molecule's physical and chemical properties. It can also determine how the molecule will react with other molecules and substances.

4. Can a molecule have more than one positive or negative pole?

Yes, a molecule can have multiple positive or negative poles. This can happen if the molecule has a complex structure or if there are multiple atoms with different electronegativities.

5. How can determining the positive and negative poles of a molecule be useful in practical applications?

Determining the positive and negative poles of a molecule can be useful in various practical applications, such as in drug design, material science, and environmental studies. It can help scientists understand the behavior and properties of different substances and develop new materials with specific properties.

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