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Greeley [361]
3 years ago
13

At 25 °C, how many dissociated OH– ions are there in 1243 mL of an aqueous solution whose pH is 2.07?

Chemistry
1 answer:
coldgirl [10]3 years ago
3 0

<u>Answer:</u> The number of OH^- ions dissociated are 8.57\times 10^{11}

<u>Explanation:</u>

We are given:

pH = 2.07

Calculating the value of pOH by using equation, we get:

2.07+pOH=14\\\\pOH=14-2.07=11.93

To calculate hydroxide ion concentration, we use the equation to calculate pOH of the solution, which is:

pOH=-\log[OH^-]

We are given:

pOH = 11.93

Putting values in above equation, we get:

11.93=-\log[OH^-]

[OH^-]=10^{-11.93}=1.17\times 10^{-12}M

To calculate the number of moles for given molarity, we use the equation:

\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}

Molarity of solution = 1.17\times 10^{-12}M

Volume of solution = 1243 mL = 1.243 L  (Conversion factor: 1 L = 1000 mL)

Putting values in above equation, we get:

1.17\times 10^{-12}M=\frac{\text{Moles of }OH^-}{1.243L}\\\\\text{Moles of }OH^-=(1.17\times 10^{-12}mol/L\times 1.243L)=1.424\times 10^{-12}mol

According to mole concept:

1 mole of a compound contains 6.022\times 10^{23} number of particles

So, 1.424\times 10^{-12}mol number of OH^- will contain = (1.424\times 10^{-12}\times 6.022\times 10^{23})=8.57\times 10^{11} number of ions

Hence, the number of OH^- ions dissociated are 8.57\times 10^{11}

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# of moles = mass/molar mass

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shepuryov [24]

Explanation:

According to Le Chatelier's principle, any disturbance caused in an equilibrium reaction will shift the equilibrium in a direction that will oppose the change.

As the given reaction is as follows.

       NH_{4}HS(s) \rightleftharpoons NH_{3}(g) + H_{2}S(g)

(a)  When increase the temperature of the reactants or system then equilibrium will shift in forward direction where there is less temperature. It is possible for an endothermic reaction.

Thus, formation of H_{2}S will increase.

  • (b)  When we decrease the volume (at constant temperature) of given reaction mixture then it implies that there will be increase in pressure of the system. So, equilibrium will shift in a direction where there will be decrease in composition of gaseous phase. That is, in the backward direction reaction will shift.

Hence, formation of H_{2}S will decrease with decrease in volume.

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3 0
3 years ago
What is the movement of water up a narrow tube due to attractions with the surface of the tube called? capillary action meniscus
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The attraction mediated flow of water in the narrow tube has been termed as Capillary action. Thus, option A is correct.

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<h3>Movement of water in a narrow tube</h3>

The surface has the force of attraction with the flowing liquids in the sample. It results in the increased surface interaction, and the liquid flows up in the tube against gravity.

The movement of the liquid in the water through a narrow tube has been termed as capillary action. Thus, option A is correct.

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brainly.com/question/1295312

6 0
2 years ago
Water has a boiling point of 100.0°C and a Kb of 0.512°C/m. What is the boiling
Reil [10]

Answer:

The boiling  point of a 8.5 m solution of Mg3(PO4)2 in water is<u> 394.91 K.</u>

Explanation:

The formula for molal boiling Point elevation is :

\Delta T_{b} = iK_{b}m

\Delta T_{b} = elevation in boiling Point

K_{b} = Boiling point constant( ebullioscopic constant)

m = molality of the solution

<em>i =</em> Van't Hoff Factor

Van't Hoff Factor = It takes into accounts,The abnormal values of Temperature change due to association and dissociation .

In solution Mg3(PO4)2 dissociates as follow :

Mg_{3}(PO_{4})_{2}\rightarrow 3Mg^{2+} + 2 PO_{4}^{3-}

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= 3 ions of Mg + 2 ions of phosphate

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<em>i =</em> Van't Hoff Factor = 5

m = 8.5 m

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Insert the values and calculate temperature change:

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\Delta T_{b} = T_{b} - T_{b}_{pure}

T_{b}_{pure} = 373.15 K[/tex]

21.76 = T - 373.15

T = 373.15 + 21.76

T =394.91 K

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