The answer to your question is D. Sound waves travel faster in more dense material, and the more dense the material the louder the sound is.
The answer is B. Equilibrium means a state in which opposing forces or influences are balanced.
Let's assume that change of pressure of PCl₅ is X
According to the ICE table,
PCl₅(g) ⇄ PCl₃(g) + Cl₂(g)
Initial Pressure 0.123 - -
Change -X +X +X
Equilibrium 0.123 - X X X
Kp = Ppcl₃(g) x Pcl₂(g) / Ppcl₅(g)
by substitution,
0.0121 = X × X / (0.123 - X)
0.0121 × (0.123 - X) = X²
1.4883 × 10⁻³ - 0.0121X = X²
X² + 0.0121X - 1.4883 × 10⁻³ = 0
X₁ = 0.03735 or X₂ = -0.03865
X cannot be a negative value since X is a pressure.
Hence,
X = 0.03735 atm
Hence, partial pressure of PCl₃ is 0.03735 atm
Tetrahedral is the answer
Physical Change: A physical change in a substance does not change what the substance is.
An example of this would be water freezing. The water looks and feels different, but it is still water, and it's chemical formula still remains H2O.
Chemical Change: A chemical change is when there is a chemical reaction and a new substance is formed because of that. The composition of the substance changes, and there is usually energy being released or absorbed.
An example of this would be burning wood. In this case, oxygen is reacting with the wood to produce ash, energy, and smoke.
