!. Which of the following structures would you expect to have a net dipole moment?
HC(triple bond)CH
NH4+
H2C(double bond)O
BCl3
2. Rank the sp, sp2, and sp3 orbitals in order of decreasing (highest to lowest) energy.
a)sp> sp2>sp3
b)sp3>sp2>sp
c)sp2>sp>sp3
d)they are all the same
i believe H2C O with the double bond is the only one with a dipole moment
HCtriplebondCH is linear and no dipole moment.
NH4^+ is tetrahedral and symetrical; therefore, no dipole moment.
H2C=O is not symmetrical in three dimensions; it has as dipole moment.
Same for BCl3.
For #2. here is come good reading.
http://chemwiki.ucdavis.edu/Organic_Chemistry/Fundamentals/Hybrid_Orbitals
i got the first one easy enough. the reading was interesting. so that leads me to believe b is the correct answer. thank you dr. bob
1. To determine which of the given structures would have a net dipole moment, we need to consider the molecular geometry and the individual bond polarity.
- HC(triple bond)CH: This is a linear molecule with a symmetrical distribution of charges on both ends of the molecule. Since the bond polarity cancels out due to its linearity, there is no net dipole moment.
- NH4+: This is known as ammonium ion. It has a tetrahedral geometry with four hydrogen atoms surrounding a central nitrogen atom. The nitrogen-hydrogen bonds have a significant electronegativity difference, resulting in polar bonds. Due to the tetrahedral symmetry, the individual dipole moments of the N-H bonds cancel out, resulting in no net dipole moment.
- H2C(double bond)O: This is the structure of formaldehyde. It has a trigonal planar geometry with an oxygen atom double-bonded to a carbon atom. The oxygen-carbon bond is polar due to the electronegativity difference. The trigonal planar geometry means that the individual dipole moments of the bonds do not cancel out, resulting in a net dipole moment.
- BCl3: This is the structure of boron trichloride. It has a trigonal planar geometry with three chlorine atoms surrounding a central boron atom. Chlorine and boron have a significant electronegativity difference, resulting in polar bonds. However, due to the trigonal planar symmetry, the individual dipole moments of the B-Cl bonds cancel out, resulting in no net dipole moment.
Therefore, the structure H2C(double bond)O would have a net dipole moment.
2. The energy order of sp, sp2, and sp3 orbitals can be determined by considering the hybridization of the orbitals.
- sp orbitals: These orbitals are formed by mixing one s and one p orbital. The energy of sp orbitals is higher than that of sp2 and sp3 orbitals due to the increased p character.
- sp2 orbitals: These orbitals are formed by mixing one s and two p orbitals. The energy of sp2 orbitals is lower than that of sp orbitals but higher than that of sp3 orbitals.
- sp3 orbitals: These orbitals are formed by mixing one s and three p orbitals. The energy of sp3 orbitals is lower than that of both sp and sp2 orbitals.
Therefore, the correct order of decreasing energy (highest to lowest) is: sp > sp2 > sp3. So the answer is (a) sp > sp2 > sp3.