We are going to use this equation:
ΔT = - i m Kf
when m is the molality of a solution
i = 2
and ΔT is the change in melting point = T2- 0 °C
and Kf is cryoscopic constant = 1.86C/m
now we need to calculate the molality so we have to get the moles of NaCl first:
moles of NaCl = mass / molar mass
= 3.5 g / 58.44
= 0.0599 moles
when the density of water = 1 g / mL and the volume =230 L
∴ the mass of water = 1 g * 230 mL = 230 g = 0.23Kg
now we can get the molality = moles NaCl / Kg water
=0.0599moles/0.23Kg
= 0.26 m
∴T2-0 = - 2 * 0.26 *1.86
∴T2 = -0.967 °C
Answer:
The equilibrium concentration of NO is 0.02124 M.
Explanation:
Given that,
Initial concentration of NOBr = 0.878 M
![k_{c}=3.07\times10^{-4}](https://tex.z-dn.net/?f=k_%7Bc%7D%3D3.07%5Ctimes10%5E%7B-4%7D)
Temperature = 24°C
We know that,
The balance equation is
![2NOBr\Rightarrow 2NO+Br_{2}](https://tex.z-dn.net/?f=2NOBr%5CRightarrow%202NO%2BBr_%7B2%7D)
Initial concentration is,
![0.878\Rightarrow 0+0](https://tex.z-dn.net/?f=0.878%5CRightarrow%200%2B0)
Concentration is,
![-2x\Rightarrow 2x+x](https://tex.z-dn.net/?f=-2x%5CRightarrow%202x%2Bx)
Equilibrium concentration
![0.878-2x\Rightarrow 2x+x](https://tex.z-dn.net/?f=0.878-2x%5CRightarrow%202x%2Bx)
We need to calculate the value of x
Using formula of concentration
![k_{c}=\dfrac{[NO][Br_{2}]}{[NOBr]^2}](https://tex.z-dn.net/?f=k_%7Bc%7D%3D%5Cdfrac%7B%5BNO%5D%5BBr_%7B2%7D%5D%7D%7B%5BNOBr%5D%5E2%7D)
Put the value into the formula
![3.07\times10^{-4}=\dfrac{[2x][x]}{[0.878-2x]^2}](https://tex.z-dn.net/?f=3.07%5Ctimes10%5E%7B-4%7D%3D%5Cdfrac%7B%5B2x%5D%5Bx%5D%7D%7B%5B0.878-2x%5D%5E2%7D)
![2x^2=3.07\times10^{-4}\times(0.878)^2+3.07\times10^{-4}\times4x^2-2\times2x\times0.878\times3\times10^{-4}](https://tex.z-dn.net/?f=2x%5E2%3D3.07%5Ctimes10%5E%7B-4%7D%5Ctimes%280.878%29%5E2%2B3.07%5Ctimes10%5E%7B-4%7D%5Ctimes4x%5E2-2%5Ctimes2x%5Ctimes0.878%5Ctimes3%5Ctimes10%5E%7B-4%7D)
![2x^2=0.0002367+0.001228x^2-0.0010536x](https://tex.z-dn.net/?f=2x%5E2%3D0.0002367%2B0.001228x%5E2-0.0010536x)
![2x^2-0.001228x^2+0.0010536x-0.0002367=0](https://tex.z-dn.net/?f=2x%5E2-0.001228x%5E2%2B0.0010536x-0.0002367%3D0)
![1.998772x^2+0.0010536x-0.0002367=0](https://tex.z-dn.net/?f=1.998772x%5E2%2B0.0010536x-0.0002367%3D0)
![x=0, 0.01062](https://tex.z-dn.net/?f=x%3D0%2C%200.01062)
We need to calculate the equilibrium concentration of NO
Using formula of concentration of NO
![concentration\ of\ NO=2x](https://tex.z-dn.net/?f=concentration%5C%20of%5C%20NO%3D2x)
Put the value of x
![concentration\ of\ NO=2\times0.01062](https://tex.z-dn.net/?f=concentration%5C%20of%5C%20NO%3D2%5Ctimes0.01062)
![concentration\ of\ NO=0.02124](https://tex.z-dn.net/?f=concentration%5C%20of%5C%20NO%3D0.02124)
Hence, The equilibrium concentration of NO is 0.02124 M.
<span>The pH is given by the Henderson - Hasselbalch equation:
pH = pKa + log([A-]/[HA])
pH = -log(</span><span>1.3 x 10^-5) + log(0.50/0.40)
pH = 4.98
The answer to this question is 4.98.
</span>
Answer:
D (The last answer)
Explanation:
In a transverse wave, particles oscillate perpendicular to the direction of wave motion.
In a longitudinal wave, the oscillations of particles are parallel to the direction of propagation.