<em>The Molecular Mass for Phosphorus is 31 grames / mole.
So, 31g. P.....................1 mole
2.3g. P ..........................x mole
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Answer:
Both are endothermic reactions.
Explanation:
Chemical equation:
1/2H₂(g) + 1/2I₂(g) → HI(g) + 6.2 kcal/mol
Chemical equation:
21.0 kcal/mol + C(s) + 2S(s) → CS₂
Both reaction are endothermic because heat is added in both of reactions.
Endothermic reactions:
The type of reactions in which energy is absorbed are called endothermic reactions.
In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.
For example:
C + H₂O → CO + H₂
ΔH = +131 kj/mol
it can be written as,
C + H₂O + 131 kj/mol → CO + H₂
Exothermic reaction:
The type of reactions in which energy is released are called exothermic reactions.
In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.
For example:
Chemical equation:
C + O₂ → CO₂
ΔH = -393 Kj/mol
it can be written as,
C + O₂ → CO₂ + 393 Kj/mol
Answer: v = 2π2 Kme2 Z / nh
Explanation:
The formula for velocity of an electron in the nth orbit is given as,
v = 2π2 Kme2 Z / nh
v = velocity
K = 1/(4πε0)
m= mass of an electron
e = Charge on an electron
Z= atomic number
h= Planck’s constant
n is a positive integer.
