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3 years ago

Which molecule has polar bonding and is nonpolar? A. H2O B. BF3 C. NH3 D. NCl3 E. CH2Cl2

Chemistry

1 answer:

Marina CMI [18]3 years ago

3 0

Answer:

B. BF₃

Explanation:

All the molecules have polar bonds, but a molecule will be nonpolar if the molecule has the symmetry that makes the bond dipoles cancel.

To make the decision, we must

Draw the Lewis structure
Assign the VSEPR electron geometry
Determine the molecular shape.
Examine the symmetry of the molecule

===============

A. Water

Lewis structure = H-O-H (2 bonding pairs, 2 lone pairs)

Electron geometry = AX₂E₂ tetrahedral

Molecular geometry = bent

Symmetry (see Figure A): The two O-H bonds are polar, with their negative ends pointing towards the O. The horizontal components of the bond dipoles cancel, but the vertical components reinforce each other and give an upward pointing molecular dipole. This is a polar molecule with polar bonds.

===============

B. Boron trifluoride

Lewis structure = BF₃ (3 bonding pairs)

Electron geometry = AX₃, trigonal planar

Molecular geometry = trigonal planar

Symmetry (see Figure B): The three B-F bonds are polar, with their negative ends pointing towards the F. The horizontal components of the bond dipoles cancel, but the vertical components of the two downward -pointing dipoles reinforce each other and give a resultant that is equal and opposite to the upward dipole. Thus, the bond dipoles cancel. This is a nonpolar molecule with polar bonds.

===============

C. Ammonia

Lewis structure = :NH₃ (3 bonding pairs, 1 lone pairs)

Electron geometry = AX₃E, tetrahedral

Molecular geometry = trigonal pyramidal

Symmetry (see Figure C): The three N-H bonds are polar, with their negative ends pointing towards the N. The horizontal components of the bond dipoles cancel, but the vertical components reinforce each other and give an upward pointing molecular dipole. This is a polar molecule with polar bonds.

===============

D. Nitrogen trichloride

Lewis structure = :NCl₃ (3 bonding pairs, 1 lone pair)

Electron geometry = AX₃E, tetrahedral

Molecular geometry = trigonal pyramidal

Symmetry (see Figure D): The three N-Cl bonds are polar, with their negative ends pointing towards the Cl. The horizontal components of the bond dipoles cancel, but the vertical components reinforce each other and give a downward pointing molecular dipole. This is a polar molecule with polar bonds.

===============

E. Dichloromethane

Lewis structure = H₂CCl₂ (4 bonding pairs)

Electron geometry = AX₄, tetrahedral

Molecular geometry = tetrahedral

Symmetry (see Figure E): The two C-H bonds are nonpolar, but the two C-Cl bonds are polar with their negative ends pointing towards the Cl. The horizontal components of the bond dipoles cancel, but the vertical components reinforce each other and give a downward pointing molecular dipole. This is a polar molecule with polar bonds.

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Strontium and chlorine combine in only one ratio: one strontium atom for every two chlorine atoms. Based on this

Vinvika [58]

The combinations of Strontium and chlorine that are possible are only those in which strontium and chlorine combine in the ratio of 1:2.

1) The possible combinations are

4 strontium atoms and 8 chlorine

$2.7 * 10^19$ strontium atoms and $5.4 * 10^19$ chlorine atoms

2) The combinations that are not possible are

20 strontium atoms and 60 chlorine atoms

130 billion strontium atoms and 195 billion chlorine

We have to work out the ratio of Strontium and chlorine in each of the given combinations in the question. Only the combinations in which the ratio of Strontium and chlorine is 1:2 is possible.

First case:

4 strontium atoms and 8 chlorine atoms gives a Strontium and chlorine ratio of 1:2 so it is possible.

Second case:

20 strontium atoms and 60 chlorine atoms gives a Strontium and chlorine ratio of 1:3 hence it is not possible.

Third case:

$2.7 * 10^19$ strontium atoms and $5.4 * 10^19$ chlorine atoms gives a Strontium and chlorine ratio of 1:2 hence it is possible.

Fourth case:

130 billion strontium atoms and 195 billion chlorine atoms gives a Strontium and chlorine ratio of 1:1.5 hence it is not possible.

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3 years ago

3. At STP, how many liters of oxygen gas are required to react completely with 3.2 x 10^22

Mrrafil [7]

The volume of oxygen required to react with 3.2 * 10²² molecules of hydrogen is 0.56 L.

<h3>What is stoichiometric law?</h3>

The stoichiometric law has been given as the representation of the moles of product and reactant in a chemical reaction are represented by the stoichiometric coefficient.

It has been known that 1 mole of a compound has 6.023 * 10²³ molecules. Thus, the moles of hydrogen gas equivalent to 3.2 * 10²² molecules has been:

6.023 * 10²³ molecules = 1 mole

3.2 * 10²² molecules = 1/6.023 * 10²³ * 3.2 * 10²² moles

3.2 * 10²² molecules = 0.05 moles

Thus, the moles of hydrogen gas available is 0.05 moles.

From the stoichiometric law, according to the balanced chemical equation,

2 moles of hydrogen requires = 1 moles of oxygen

0.05 moles of hydrogen requires = 1/2 * 0.05 moles oxygen

0.05 moles of hydrogen requires = 0.025 moles oxygen

Thus, the moles of oxygen required is 0.025 moles. At STP, a mole of gas been equivalent to 22.4 L . Thus, the volume of 0.025 moles oxygen has been:

1 mole = 22.4 L

0.025 moles = 22.4 * 0.025 L

0.025 mole = 0.56 L

Thus, the volume of oxygen required to react with 3.2 * 10²² molecules of hydrogen is 0.56 L.

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2 years ago

9. A box is pushed 1.5 m to the right in 5 s. What is the box’s average speed to the nearest hundredth of a m/s? *

poizon [28]

Answer:

s = 0.30 m/s

Explanation:

Given data:

Distance travel = 1.5 m

Time taken = 5 s

Average speed of box = ?

Solution:

s = d/t

s = speed

d = distance

t = time

by putting values,

s = 1.5 m/ 5 s

s = 0.30 m/s

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2 years ago

One way to determine the degree of saturation of a solid-liquid solution is to drop a crystal of the solute into the solution.

Dafna1 [17]

The answer is D: Saturated.

A saturated solution is one in which the exact maximum amount of solute has been dissolved. So, new solute will not dissolve in the solution. In contrast, an unsaturated solution can hold more solute, so if that option were correct, the crystal would have dissolved.

The other two terms are a bit more complicated. A supersaturated solution is one holding an amount of solute above the sustainable limit. Because of that, when more solute is added, the solution will immediately adjust, and some solute will come out of solution in a precipitate. Because the crystal isn't growing, we can eliminate this option.

A concentrated solution is one holding a relatively large amount of solute. However, you can have concentrated solutions that are saturated and unconcentrated (the word for this is dilute) solutions that aren't saturated. Therefore, we can say that because the crystal doesn't dissolve, this solution is saturated, but we can't say with certainty that it is concentrated.

Because the first three options are invalid, as described above, while the scenario does describe a saturated solution, D is the correct answer.

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3 years ago

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Write the name for: Mg3O2

sveticcg [70]

Answer:

you sure it is the right sign your using

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2 years ago