The weighted average atomic mass of Silicon is 28.1
(27.98 x .9223) + (28.98 x .0468) + (29.97 x .0309)
= 25.81 + 1.36 + .93
= 28.1
Answer:
ΔSv = 0.1075 KJ/mol.K
Explanation:
Binary solution:
∴ a: solvent
∴ b: solute
in equilibrium:
- μ*(g) = μ(l) = μ* +RTLnXa....chemical potential (μ)
⇒ Ln (1 - Xb) = ΔG/RT
∴ ΔG = ΔHv - TΔSv
⇒ Ln(1 -Xb) = ΔHv/RT - ΔSv/R
∴ Xb → 0:
⇒ Ln(1) = ΔHv/RT - ΔSv/R
∴ T = T*b....normal boiling point
⇒ 0 = ΔHv/RT*b - ΔSv/R
⇒ ΔSv = (R)(ΔHv/RT*b)
⇒ ΔSv = ΔHv/T*b
∴ T*b = 80°C ≅ 353 K
⇒ ΔSv = (38 KJ/mol)/(353 K)
⇒ ΔSv = 0.1075 KJ/mol.K
Light does not travel at a constant speed in a vacuum, compared to in air, because the light is being absorbed by atoms and molecules in the air. But light does travel at a constant speed in a vacuum.
So I agree with A
All that talk about moving forward is irrelevant (I think)
Answer:
Among Na ,K , Pb , Li , The atom which does not react with water is :
<u>Pb</u>
Explanation:
Li : Reacts slowly with water
Na ,K : Reacts vigorously with water
Pb : It does not reacts with water because :- Pb oxidize in presence of atmospheric oxygen to form lead oxide (PbO) . this PbO form a layer over the surface of Pb and make it inert to water.
