Xe +f2 →Xef2
ΔXe = ΣB.P reactants - Σ B.d products
-108k.s/ mol = B. D f₂ - 2 B.D xe-f
-108 k.s/mol =155 k.s/mol - 2B.Dxe-f
263kJ/mol/2 = B. D xe-f
B.D xef = 131.5 kJ/mol
132 kJ/mol
Generally bonds present between molecules are called intermolecular forces. they are three types:
1) Wander Wall forces (London forces)
2) Dipole - dipole interaction.
3) Hydrogen bond.
- As molecular weight increases boiling point also increases due to surface are is directly proportional to Wander Waal forces.
- Dipole-dipole attraction: the attraction between two different polarizable molecules is called dipole- dipole attraction, this attraction play important role in boiling point.
- Hydrogen bond: electrostatic attraction between hydrogen and more electronegative atom is called hydrogen bond.
- The substance which has hydrogen bond have higher boiling point.
1-pentanol has hydrogen bond
1- Bromopentane has dipole - dipole
1-pentene has only London forces
Hydrogen bond > dipole - dipole attraction > London force
Number of photons can be calculated by dividing the needed energy by the energy per photon.
The minimum energy needed is given as 2 x 10^-17 joules
Energy per photon = hc / lambda where h is planck's constant, c is the speed of light and lambda is the wavelength
Energy per photon = (<span>6.626 x 10^-34 x 3 x 10^8) / (475 x 10^-9)
= 4.18 x 10^-19 J
number of photons = (2 x 10^-17) / (4.18 x 10^-19)
= 47.79 photons which is approximately 48 photons</span>
Answer:
I might be wrong but i believe the answer would be A.
Explanation:
I think its A. because:
The unified cell theory states that all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
