How many moles of hydrogen gas<br> are produced when 3.8 moles of HCI<br> are reacted?<br> O 1.9 mol

A titration of 25.0 mL of a solution of the weak base aniline, C6H5NH2, requires 25.67 mL of 0.175 M HCl to reach the equivalenc

Lorico [155]

Answer:

a. 0.180M of C₆H₅NH₂

b. 0.0887M C₆H₅NH₃⁺

c. pH = 2.83

Explanation:

a. Based in the chemical equation:

C₆H₅NH₂(aq) + HCl(aq) → C₆H₅NH₃⁺(aq) + Cl⁻(aq)

<em>1 mole of aniline reacts per mole of HCl</em>

Moles required to reach equivalence point are:

Moles HCl = 0.02567L ₓ (0.175mol / L) = 4.492x10⁻³ moles HCl = moles C₆H₅NH₂

As the original solution had a volume of 25.0mL = 0.0250L:

4.492x10⁻³ moles C₆H₅NH₂ / 0.0250L = 0.180M of C₆H₅NH₂

b. At equivalence point, moles of C₆H₅NH₃⁺ are equal to initial moles of C₆H₅NH₂, that is 4.492x10⁻³ moles

But now, volume is 25.0mL + 25.67mL = 50.67mL = 0.05067L. Thus, molar concentration of C₆H₅NH₃⁺ is:

[C₆H₅NH₃⁺] = 4.492x10⁻³ moles / 0.05067L = 0.0887M C₆H₅NH₃⁺

c. At equivalence point you have just 0.0887M C₆H₅NH₃⁺ in solution. C₆H₅NH₃⁺ has as equilibrium in water:

C₆H₅NH₃⁺(aq) + H₂O(l) → C₆H₅NH₂ + H₃O⁺

Where Ka = Kw / Kb = 1x10⁻¹⁴ / 4.0x10⁻¹⁰ =

When the system reaches equilibrium, molar concentrations are:

[C₆H₅NH₃⁺] = 0.0887M - X

[C₆H₅NH₂] = X

[H₃O⁺] = X

Replacing in Ka formula:

2.5x10⁻⁵ = [X] [X] / [0.0887M - X]

2.2175x10⁻⁶ - 2.5x10⁻⁵X = X²

0 = X² + 2.5x10⁻⁵X - 2.2175x10⁻⁶

Solving for X:

X = -0.0015 → False solution. There is no negative concentrations.

X = 0.001477 → Right solution.

As [H₃O⁺] = X, [H₃O⁺] = 0.001477

Knowing pH = -log [H₃O⁺]

pH = -log 0.001477

7 0

2 years ago

A solution is prepared by dissolving 106.3 g HCl(g) in enough water to make 175.0 L of solution. The ph of this solution is

DedPeter [7]

Answer:

moles HCl = 101.2 g /36.461 g/mol=2.78

[H+]= 2.78 mol/ 150 L =0.0185

pH = - log 0.0185=1.73

1.73 is the answer

3 0

3 years ago

It takes to break an iodine-iodine single bond. Calculate the maximum wavelength of light for which an iodine-iodine single bond

Zolol [24]

The given question is incomplete. The complete question is :

It takes 151 kJ/mol to break an iodine-iodine single bond. Calculate the maximum wavelength of light for which an iodine-iodine single bond could be broken by absorbing a single photon. Be sure your answer has the correct number of significant digits.

Answer: 793 nm

Explanation:

The relation between energy and wavelength of light is given by Planck's equation, which is:

$E=\frac{hc}{\lambda}$

where,

E = energy of the light = 151 kJ= 151000 J (1kJ=1000J)

N= moles = 1 = $6.023\times 10^{23}$

h = Planck's constant = $6.626\times 10^{-34}Js$

c = speed of light = $3\times 10^8m/s$

$\lambda$ = wavelength of light = ?

Putting in the values:

$151000J=\frac{6.023\times 10^{23}\times 6.626\times 10^{-34}Js\times 3\times 10^8m/s}{\lambda}$

${\lambda}=7.93\times 10^{-7}m=793nm$ $1m=10^{-9}nm$

Thus the maximum wavelength of light for which an iodine-iodine single bond could be broken by absorbing a single photon is 793 nm

3 0

2 years ago

Sn=0.14 (E) <br>Sn+2 = -0.15(E) <br>Which form of tin is the stronger reducing agent? OS O Sn +2?

fomenos

0.14

Explanation:

I just needed to finish setting up my account

3 0

2 years ago

What energy transformations occur each time the skateboarder rolls up on the ramp? ( I will try to mark you ) (7th grade science

ZanzabumX [31]

Answer:

Kinetic energy is energy of motion. The faster skaters move, the more kinetic energy they have. In a halfpipe, energy is constantly transformed between potential (at the top) and kinetic (as they travel down the sides) as the skater goes back and forth between the ramps.

Explanation:

6 0

2 years ago

How many moles of hydrogen gas are produced when 3.8 moles of HCI are reacted? O 1.9 mol