The correct answer is option B, that is, the pitch changes from low to high.
The Doppler shift or the Doppler Effect refers to the variation in the wavelength or frequency of a wave in association with an observer who is traveling comparative to the source of the wave. A prime illustration of Doppler shift is the modification of the pitch heard when a vehicle sounding a horn comes towards and move away from an observer.
In comparison to the frequency emitted, the obtained frequency is greater at the time of approach, similar at the instant of passing by, and lower at the time of recession.
Answer:
(a) 
(b) 
(c) 
(d) 
Explanation:
Hello,
In this case, we define the pH in terms of the concentration of hydronium ions as:
![pH=-log([H^+])](https://tex.z-dn.net/?f=pH%3D-log%28%5BH%5E%2B%5D%29)
Which is directly computed for the strong hydrochloric acid (consider a complete dissociation which means the concentration of hydronium equals the concentration of acid) in (a) and (c) as shown below:
(a)
![[H^+]=[HCl]=0.1M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BHCl%5D%3D0.1M)
(b)
![[H^+]=[HCl]=0.05M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BHCl%5D%3D0.05M)

Nevertheless, for the strong sodium hydroxide, we don't directly compute the pH but the pOH since the concentration of base equals the concentration hydroxyl in the solution:
![[OH^-]=[NaOH]](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D%5BNaOH%5D)
![pOH=-log([OH^-])](https://tex.z-dn.net/?f=pOH%3D-log%28%5BOH%5E-%5D%29)

Thus, we have:
(b)

(d)

Best regards.
in solid matter, atoms or molecules pack close to each other in fixed locations; in gases, atoms or molecules pack about as closely as they do in solid matter, but they are free to move;
Answer:
d) 2.7 mol
Explanation:
limit reagent is H2:
∴ Mw H2 = 2.016 g/mol
∴ Mw N2 = 28.0134 g/mol
⇒ moles NH3 = (4.0 moles H2)×(2 mol NH3/3mol H2)
⇒ moles NH3 = 2.666 mol
⇒ moles NH3 ≅ 2.7 mol
Answer:
Hi.. U should do like this
Cu + S - - - >Cu2S