Answer:In ionic compounds, electrons are transferred between atoms of different elements to form ions. But this is not the only way that compounds can be formed. Atoms can also make chemical bonds by sharing electrons equally between each other. Such bonds are called covalent bonds. Covalent bonds are formed between two atoms when both have similar tendencies to attract electrons to themselves (i.e., when both atoms have identical or fairly similar ionization energies and electron affinities). For example, two hydrogen atoms bond covalently to form an H2 molecule; each hydrogen atom in the H2 molecule has two electrons stabilizing it, giving each atom the same number of valence electrons as the noble gas He.
Compounds that contain covalent bonds exhibit different physical properties than ionic compounds. Because the attraction between molecules, which are electrically neutral, is weaker than that between electrically charged ions, covalent compounds generally have much lower melting and boiling points than ionic compounds. In fact, many covalent compounds are liquids or gases at room temperature, and, in their solid states, they are typically much softer than ionic solids. Furthermore, whereas ionic compounds are good conductors of electricity when dissolved in water, most covalent compounds are insoluble in water; since they are electrically neutral, they are poor conductors of electricity in any state.
Answer:
7.41 × 10⁻⁵
Explanation:
Let's consider the basic dissociation reaction of trimethylamine (CH₃)N).
(CH₃)N + H₂O = (CH₃)NH⁺ + OH⁻
According to Brönsted-Lowry, in this reaction (CH₃)N is a base and (CH₃)NH⁺ is its conjugate acid. The pKb for (CH₃)N is 9.87. We can calculate the pKa of (CH₃)NH⁺ using the following expression.
pKa + pKb = 14
pKa = 14 - pKb = 14 - 9.87 = 4.13
Then, we can calculate the acid dissociation constant for (CH₃)NH⁺ using the following expression.
pKa = -log Ka
Ka = antilog - pKa = antilog -4.13 = 7.41 × 10⁻⁵
Answer:
The partial pressure of the other gases is 0.009 atm
Explanation:
Step 1: Data given
Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules and 1% of other gases.
The atmospheric pressure = 0.90 atm
Step 2: Calculate mol fraction
If wehave 100 moles of air, 78 moles will be nitrogen,
21 moles will be oxygen, and 1 mol will be other gases.
Mol fraction = 1/100 = 0.01
Step 3: Calculate the partial pressure of the other gases
Pgas = Xgas * Ptotal
⇒ Pgas = the partial pressure = ?
⇒ Xgas = the mol fraction of the gas = 0.01
⇒Ptotal = the total pressure of the pressure = 0.90 atm
Pgas = 0.01 * 0.90 atm
Pgas = 0.009 atm
The partial pressure of the other gases is 0.009 atm
Answer:
The number of moles =
The number of molecules =
Explanation:
Volume of the sphere is given by :
here, r = radius of the sphere
Radius = 3 mm
r = 3 mm
1 mm = 0.01 dm (1 millimeter = 0.001 decimeter)
3 mm = 3 x 0.01 dm = 0.03 dm
r = 0.03 dm
<em>("volume must be in dm^3 , this is the reason radius is changed into dm"</em>
<em>"this is done because 1 dm^3 = 1 liter and concentration is always measured in liters")</em>
(1 L = 1 dm3)
Now, concentration "C"=
The concentration is given by the formula :
This is also written as,
moles
One mole of the substance contain "Na"(= Avogadro number of molecules)
So, "n" mole of substance contain =( n x Na )
Molecules =
molecules
Answer:
If the numbers of each type of atom are different on the two sides of a chemical equationExplanation:
