Answer:
Option 4. There's no hydrogen bonding between HBr molecules at all.
Explanation:
<h3>SiH₄</h3>
SiH₄ molecules are tetrahedral and symmetric. Dipoles due to the polar Si-H bonds balance each other. SiH₄ molecules are nonpolar. Only instantaneous dipoles are possible between those molecules.
<h3>C₆H₆ Benzene</h3>
Similar to SiH₄, benzene is symmetric. Dipoles due to the weakly polar C-H bonds balance each other. Benzene molecules are nonpolar. Only instantaneous dipoles are possible between those molecules.
<h3>NH₃</h3>
There are two conditions for hydrogen bonding to take place:
- H atoms are directly bonded to a highly electronegative element: Nitrogen, Oxygen, or Fluorine.
- There is at least one lone pair of electrons nearby.
Consider the Lewis structure of NH₃. There are three H atoms in each NH₃ molecule. Each of the three H atoms is bonded directly to the N atom with a highly polar N-H bond. Also, there is a lone pair of electrons on the N atom. Hydrogen bonding will take place between NH₃ molecules.
NH₃ is a relatively small molecule. As a result, hydrogen bonding will be the dominant type of intermolecular force between NH₃ molecules.
<h3>HBr</h3>
There are three lone pairs on the Br atom in each HBr molecule. However, no H atom is connected to any one of the three highly electronegative elements: N, O, or F. The Br atom isn't electronegative enough for the H atom to form hydrogen bonding. HBr molecules are polar. As a result, the dominant type of intermolecular forces between HBr molecules will be dipole-dipole interactions (A.k.a. permanent dipole.)
<h3>CaO</h3>
Calcium is a group 2 metal. Oxygen is one of the three most electronegative nonmetal. (Again, the most electronegative elements are: Nitrogen, Oxygen, and Fluorine.) As a main group metal, Ca atoms tend to lose electrons and form positive ions. Oxygen will gain those electrons to form a negative ion. As a result, CaO will be an ionic compound full of Ca²⁺ and O²⁻ ions. Forces between ions with opposite charges are called ionic bonds.
Explanation:
Compounds are the species in which all the components react chemically to form a molecule which has a different property from the constituting elements.
On the other hand, mixture are the species in which the components do not react chemically and the original properties of the components are not lost.
<u>Thus, separation of the mixture into its components can be done by the physical means while separation of the compound into its components can be only possible by the chemical means.</u>
The lattice energy is the amount of energy released when the ions that make up a crystal lattice are brought together. Now, this energy is dependent on the charge concentration of these ions. Both potassium and rubidium form ions with a +1 charge, while bromine and iodine form ions with -1 charge. However, because potassium and bromine are smaller than rubidium and iodine respectively, the charge is more concentrated. Therefore, more energy is released when potassium and bromine are brought together.
Oxygen atoms are all different whereas hydrogen atoms are the same but also lighter
Answer:
the specimen has 11460 years old
Explanation:
if the live sample has as initial amount of Yo C14, the dead sample will have 0.25Yo of C14.
the rate of decay of radiactive matter over time is
- Y(t) = Yo * e (( - t * Ln2 ) / T)
∴ Y(t) = 0.25Yo; T = 5730
⇒ 0.25Yo = Yo * e (( - t * Ln2 ) / 5730 )
⇒ 0.25 = e (( - t * Ln2 ) / 5730 )
⇒ Ln(0.25) = ( - t * Ln2 ) / 5730
⇒ - 7943.466 = - t * Ln2
⇒ 7943.466 / Ln2 = t
⇒ t = 11460 year
