H2(g) +C2H4(g)→C2H6(g)
H-H +H2C =CH2→H3C-Ch3
2C -H bonds and one C-C bond are formed while enthalpy change (dH) of the reaction,
H-H: 432kJ/mol
C=C: 614kJ/mol
C-C: 413 kJ/mol
C-C: 347 kJ/mol
dH is equal to sum of the energies released during the formation of new bonds or negative sign, and sum of energies required to break old bonds or positive sign.
The bond which breaks energy is positive.
432+614 =1046kJ/mol
Formation of bond energy is negative
2(413) + 347 = 1173 kJ/mol
dH reaction is -1173 + 1046 =-127kJ/mol
<u>Answer 2 :</u> The given electronic configuration for a neutral atom of phosphorous in its ground state is incorrect.
Explanation :
A neutral atom of phosphorous has 15 electrons.
The given electronic configuration is incorrect.
The reason is, According to Aufbau principle, the electrons will be first filled in the sub-shell having lower orbital energy. As from the given configuration, 3p sub-shell has lower orbital energy than 4s sub-shell. So, the electrons will be filled in 3p sub-shell first. Hence, the ground state electronic configuration of neutral atom of phosphorous is,

<u>Answer 3 :</u>
Element Rubidium Magnesium Aluminium
Symbol Rb Mg Al
Group number 1 2 13
Number of valence 1 2 3
electrons
The order of general reactivity on the basis of number of valence electrons.
Rb > Mg > Al
Reason : The reactivity is determined by the number of electrons present in the outermost shell that means the element which have 1 valence electron will be more reactive because they can easily lose electrons.
Answer:
0.080 mol
Explanation:
M(HCl) = (1.0 +35.5) g/mol = 36.5 g/mol
2.9g*1mol/36.5 g = 0.0795 mol HCl
Ca(OH)2 + 2HCl ---> CaCl2 + 2H2O
from reaction 2 mol 2 mol
given 0.0795 mol x mol
x = 0.0795 mol ≈0.080 mol
Answer:
a. decrease the amount of the common ion in the system
Explanation:
The correct option is - a. decrease the amount of the common ion in the system
Reason -
Adding a common ion decreases solubility, as the reaction shifts toward the left to relieve the stress of the excess product.
Adding a common ion to a dissociation reaction causes the equilibrium to shift left, toward the reactants, causing precipitation.