Answer:
Yes, the chemist can determine which compound is in the sample.
Explanation:
In 1 mole of K₂O, the mass of K is 2 × 39.1 g = 78.2 g and the mass of K₂O is 94.2 g. The mass ratio of K to K₂O is 78.2 g / 94.2 g = 0.830.
In 1 mole of K₂O₂, the mass of K is 2 × 39.1 g = 78.2 g and the mass of K₂O₂ is 110.2 g. The mass ratio of K to K₂O₂ is 78.2 g / 110.2 g = 0.710.
If the chemist knows the mass of K and the mass of the sample, he or she must calculate the mass ratio of K to the sample.
- If the ratio is 0.830, the compound is pure K₂O.
- If the ratio is 0.710, the compound is pure K₂O₂.
- If the ratio is not 0.830 or 0.710, the sample is a mixture.
m = given mass of gas = 3.82 g
M = molar mass of gas = ?
T = temperature of laboratory = 302 K
P = air pressure = 1.04 atm = 1.04 x 101325 pa
V = volume of gas = 0.854 L = 0.854 x 10⁻³ m³
using the ideal gas equation
PV = (m/M) RT
inserting the above values
(1.04 x 101325) (0.854 x 10⁻³) = (3.82/M) (8.314) (302)
M = 106.6 g
hence the molar mass of the gas comes out to be 106.6 g
Answer:
Removal of Third Electron
Explanation:
a major jump is required to remove the third electron. In general, successive ionization energies always increase because each subsequent electron is being pulled away from an increasingly more positive ion.
Ionization energy increases from bottom to top within a group, and increases from left to right within a period.
Answer:
35 KJ.
Explanation:
The activation energy is the minimum energy that must be overcome for a reaction to take place.
In the diagram given above, the activation energy lies between the energy of the reactants and that at the peak.
Thus we can calculate the activation energy as follow:
Energy of reactants = 30 KJ
Energy at the peak = 65 KJ
Activation energy =..?
Activation energy = Energy at the peak – Energy of reactants
Activation energy = 65 – 30
Activation energy = 35 KJ
Therefore, the activation energy of th reaction is 35 KJ
The answer is:
a)0.25%
b) metallic bond
The explanation:
A) The percentage of ionic character in a compound having some covalent character can be calculated by the following equation. The percent ionic character = Observed dipole moment/Calculated dipole moment assuming 100% ionic bond × 100.
-The percent ionic character is a function of the electron negativities of the ions XA and XB . The electronegativities for Al and Mn are 1.5 and 1.6, respectively
:
when %IC = [1-exp(-1/4) (XB-XA)^2].100
so, %IC = [1 - exp(- 0.25)(1.6- 1.5)^2] . 100 = 0.25%
(b) Because the percent ionic character is so small (0.25%) and this intermetallic compound is composed of two metals Al and Mn, the bonding is completely metallic.
Metallic bond:
• Metallic bonding can be either weak (68 kJ/mole or 0.7 eV/atom for Hg) or strong (850 kJ/mole or 8.8 eV/atom for W)
• Metallic bonding gives rise to high electrical and thermal conductivity.
-The electrons are loosely held since each atom has several unoccupied valence orbitals; it is relatively easy for the electrons to move about. In this manner the electrons allow atoms to slide past each other.
