The United States was the first modern

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

3 years ago

2. Soil is made of <br> A. air<br> B. rocks<br> C. decomposed leaves<br> D. all of the above

Irina18 [472]

Answer:

B

Explanation:

<h2>Soil is a mixture of </h2><h2 /><h2>tiny particles of rock,</h2>

<h2>dead plants and animals </h2>

<h2>,air and water.</h2>

3 0

3 years ago

Read 2 more answers

Always carry the microscope with________________-one on the ____________ and one underneath the____________ of the microscope

Ronch [10]

Answer:

Always carry the microscope with two hands. One on the arm and one underneath the base of the microscope.

5 0

3 years ago

When you put aspirated spinach leaf disks in a beaker of sodium bicarbonate and place them in different colors of light, some di

juin [17]

The release of O₂( oxygen) from the process of photosynthesis is what made them to be able to float.

<h3>What is Photosynthesis?</h3>

This is referred to as the process in which green plants manufacture their food in the presence of sunlight which is trapped by chlorophyll.They are known as primary producers and they use compounds such as water and carbondioxide.

The reactants mentioned above undergo series of reactions which leads to the production of glucose and oxygen is given off as a result which is the element responsible for the floating of the aspirated spinach leaf disks in this scenario.

Read moire about Photosynthesis here brainly.com/question/19160081

#SPJ1

3 0

1 year ago

C3H8+5O2a3CO2 +4H2O is an example of a __________ chemical reaction. A. synthesis. B. combustion. C. replacement. D. synthesis a

lina2011 [118]

B .combustion because HOH and CO2 are the products of complete combustion

7 0

3 years ago