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3 years ago

15

You are given a clear-water solution containing potassium nitrate. How could you determine whether the solution is unsaturated,

saturated, or supersaturated?

1 answer:

igor_vitrenko [27]3 years ago

5 0

Answer:

If it is unsaturated, we can dissolve some more amounts of potassium nitrate into it Explanation:

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A standard solution of FeSCN2+ is prepared by combining 9.0 mL of 0.20 M Fe(NO3)3 with 1.0 mL of 0.0020 M KSCN . The standard so

Xelga [282]

Answer : The equilibrium concentration of $SCN^-$ in the trial solution is $4.58\times 10^{-8}M$

Explanation :

First we have to calculate the initial moles of $Fe^{3+}$ and $SCN^-$ .

$\text{Moles of }Fe^{3+}=\text{Concentration of }Fe^{3+}\times \text{Volume of solution}$

$\text{Moles of }Fe^{3+}=0.20M\times 9.0mL=1.8mmol$

and,

$\text{Moles of }SCN^-=\text{Concentration of }SCN^-\times \text{Volume of solution}$

$\text{Moles of }SCN^-=0.0020M\times 1.0mL=0.0020mmol$

The given balanced chemical reaction is,

$Fe^{3+}(aq)+SCN^-(aq)\rightleftharpoons FeSCN^{2+}(aq)$

Since 1 mole of $Fe^{3+}$ reacts with 1 mole of $SCN^-$ to give 1 mole of $FeSCN^{2+}$

The limiting reagent is, $SCN^-$

So, the number of moles of $FeSCN^{2+}$ = 0.0020 mmole

Now we have to calculate the concentration of $FeSCN^{2+}$ .

$\text{Concentration of }FeSCN^{2+}=\frac{0.0020mmol}{9.0mL+1.0mL}=0.00020M$

Using Beer-Lambert's law :

$A=\epsilon \times C\times l$

where,

A = absorbance of solution

C = concentration of solution

l = path length

$\epsilon$ = molar absorptivity coefficient

$\epsilon$ and l are same for stock solution and dilute solution. So,

$\epsilon l=\frac{A}{C}=\frac{0.480}{0.00020M}=2400M^{-1}$

For trial solution:

The equilibrium concentration of $SCN^-$ is,

$[SCN^-]_{eqm}=[SCN^-]_{initial}-[FeSCN^{2+}]$

$[SCN^-]_{initial}$ = 0.00050 M

Now calculate the $[FeSCN^{2+}]$ .

$C=\frac{A}{\epsilon l}=\frac{0.220}{2400M^{-1}}=9.17\times 10^{-5}M$

Now calculate the concentration of $SCN^-$ .

$[SCN^-]_{eqm}=[SCN^-]_{initial}-[FeSCN^{2+}]$

$[SCN^-]_{eqm}=(0.00050M)-(9.17\times 10^{-5}M)$

$[SCN^-]_{eqm}=4.58\times 10^{-8}M$

Therefore, the equilibrium concentration of $SCN^-$ in the trial solution is $4.58\times 10^{-8}M$

5 0

4 years ago

Which of the following statements is true?

dybincka [34]

Answer:C

Explanation:

A process is called spontaneous if the process takes place on its own without the intervention of external factors.

The spontaneous processes are generally quick with observable rates of reaction.But processes can be spontaneous even with negligible rates of reaction.

Spontaneity of reactions depend on temperature.

This is because spontaneity is measured by gibbs energy or enthalpy.

Both of these measures are dependent on temperature.

So,temperature affects spontaneity.

7 0

3 years ago

The rotational period of the moon is_____

Ivahew [28]

Answer:

Hi, I think the D since the moon rotates about once a month and these months have different amounts of days. an example would be February that can have like 28 or 29 in leap year

Explanation:

6 0

3 years ago

Please help me and I’ll give you brainiest!!!!!!!!! <br><br><br><br> Have a wonderful day!!:)))

Step2247 [10]

Answer:

up down up down thats the pattern

Explanation:

5 0

3 years ago

Calculate the enthalpy for the reaction D + F = G + H using

Iteru [2.4K]

The enthalpy for the reaction : ΔH = -132

<h3>Further explanation</h3>

Given

Reaction and the enthalpy

Required

the enthalpy

Solution

Hess Law

Reaction 1 reverse :

A + B = G + C ΔH = -277

Reactions 2 and 3 remain the same (unchanged)

C + F = A ΔH = 303

D = B + H ΔH = -158

Add up all the reactions and remove the same compound from two different sides

D + F = G + H ΔH = -132

5 0

3 years ago