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.
Answer:
100.71 cm H2O
Explanation:
In a fluid column barometer, the height of the fluid column is proportional to the pressure. The pressure is by definition:
, where F is a force and A is the area.
In a column barometer the force is given by the weight of the fluid:
, and the mass may be expressed as 
, where 
is the density and V is the volume.
Replacing this in the pressure definition:
In a constant cross section area column, the volume may be calculated as:
where A is the area and h the height. Replacing this in the previous equation:
Different columns may be over the same pressure, so:
Dividing each part for gravity constant:
And isolating hw:
mm
It is equal to 1007,1 cm.
<span>Beta decay increases the atomic number by 1, and does not change the mass number. 28Mg12 → 0e-1 + 28Al13</span>
Answer:
In this phenomenon we talk about ideal gases, that is why in these equations the constant is the number of moles and the constant R, which has a value of 0.082
Explanation:
The complete equation would have to be P x V = n x R x T
where n is the number of moles, and if it is not clarified it is because they remain constant, as the question was worded.
On the other hand, the symbol R refers to the ideal gas constant, which declares that a gas behaves like an ideal gas during the reaction, and its value will always be the same, which is why it is called a constant. The value of R = 0.082.
The ideal gas model assumes that the volume of the molecule is zero and the particles do not interact with each other. Most real gases approach this constant within two significant figures, under pressure and temperature conditions sufficiently far from the liquefaction or sublimation point. The real gas equations of state are, in many cases, corrections to the previous one.
The universal constant of ideal gases is not a fundamental constant (therefore, choosing the temperature scale appropriately and using the number of particles, we can have R = 1, although this system of units is not very practical)
Mg(OH)2
Mg: 1
O: 2
H: 2
Mg. O H
24.3g 32g. 2
58.3g in 1 mol of Mg(OH)2
3.2mol of Mg(OH)2 x 58.3g of Mg(OH)2
-------------------------
1 mol of Mg(OH)2
= 186.56 g of Mg(OH)2 in 3.2 mols of Mg(OH)2
