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Ronch [10]
2 years ago
11

A 0.068 M solution of benzamide has a pOH of 2.91. What is the value of Kb for this compound?

Chemistry
1 answer:
igor_vitrenko [27]2 years ago
5 0

Answer:

Kb = 2.23 x 10⁻⁵

Explanation:

Benz-CO-NH₂ + H₂O => Benz-CO-NH₃⁺OH⁻ ⇄ Benz-CO-NH₃⁺ + OH⁻

given pOH = 2.91 => [OH⁻] = 10E-2.91 = 1.23 x 10⁻³M

                         Benz-CO-NH₃⁺OH⁻ ⇄ Benz-CO-NH₃⁺   +       OH⁻

At Equilibrium           0.68M                    1.23 x 10⁻³M          1.23 x 10⁻³M

Kb = [Benz-CO-NH₃⁺][OH⁻]/[ Benz-CO-NH₃⁺OH⁻]

= (1.23 x 10⁻³)² M²/ 0.068M = 2.23 x 10⁻⁵

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You notice that the water in your friend's swimming pool is cloudy and that the pool walls are discolored at the water line. A q
Flauer [41]

Answer:

6,78 mL of 12,0 wt% H₂SO₄

Explanation:

The equilibrium in water is:

H₂O (l) ⇄ H⁺ (aq) + OH⁻ (aq)

The initial concentration of [H⁺] is 10⁻⁸ M and final desired concentration is [H⁺] = 10^{-7,20}, thus,

Thus, you need to add:

[H⁺] = 10^{-7,2} -10^{-8,0} = 5,31x10⁻⁸ M

The total volume of the pool is:

9,00 m × 15,0 m ×2,50 m = 337,5 m³ ≡ 337500 L

Thus, moles of H⁺ you need to add are:

5,31x10⁻⁸ M × 337500 L = 1,792x10⁻² moles of H⁺

These moles comes from

H₂SO₄ → 2H⁺ +SO₄²⁻

Thus:

1,792x10⁻² moles of H⁺ × \frac{1H_{2}SO_4 mol}{2H^{+} mol} = 8,96x10⁻³ moles of H₂SO₄

These moles comes from:

8,96x10⁻³ moles of H₂SO₄ × \frac{98,1 g}{1 mol} × \frac{100 gSolution}{12 gH_{2}SO_4 } × \frac{1 mL}{1,080 g}  =

6,78 mL of 12,0wt% H₂SO₄

I hope it helps!

8 0
3 years ago
How salt solution can be determined by using hydrometer​
goldenfox [79]

Answer:

Salt solution may be calculated by measuring the specific gravity of a sample of water using a hydrometer.

<em>Hope</em><em> this</em><em> answer</em><em> correct</em><em> </em><em>(</em><em>^</em><em>^</em><em>)</em><em>.</em><em>.</em><em>.</em><em>.</em>

3 0
3 years ago
Gold atoms can be identified based on the number of which subatomic particles?
sp2606 [1]

Answer: A

Explanation:

A Gold (Au) atom has 79 protons and 79 electrons. A typical gold atom has 118 neutrons, though there are 18 other radioisotopes discovered so far. 79 is its charge (atomic number), which is both its proton number and electron number

7 0
2 years ago
Read 2 more answers
A 1.2 kg sample of Th-228 has a half-life of 1.9 years. How many grams of Th is left after 13.3 years?
Bumek [7]
.009375 kg or 9.375 grams will remain
7 0
3 years ago
The reactant concentration in a first-order reaction was 8.10×10−2 M M after 15.0 s s and 1.80×10−3 M M after 90.0 s s . What is
kipiarov [429]

Answer:

The answer to the question is

The rate constant for the reaction is 1.056×10⁻³ M/s

Explanation:

To solve the question, e note that

For a zero order reaction, the rate law is given by

[A] = -k×t + [A]₀

This can be represented by the linear equation y = mx + c

Such that y = [A], m which is the gradient is = -k, and the intercept c = [A]₀

Therefore the rate constant k which is the gradient is given by

Gradient = \frac{[A]_{2} - [A]_{1}  }{t_{2} - t_{1}  }  where [A]₁ = 8.10×10⁻² M and [A]₂ = 1.80×10⁻³ M

= \frac{1.80*10^{-3} M- 8.10*10^{-2} M}{90 s - 15 s} = -0.001056 M/s = -1.056×10⁻³ M/s

Threfore k = 1.056×10⁻³ M/s

3 0
3 years ago
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