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omeli [17]
2 years ago
15

The standard curve was made by spectrophotographic analysis of equilibrated iron(III) thiocyanate solutions of known concentrati

on. You are asked to analyze a Fe(SCN)2+ solution with an unknown concentration and an absorbance value of 0.410 . The slope-intercept form of the equation of the line is y=4541.6x+0.0461 . The unknown was analyzed on the same instrument as the standard curve solutions at the same temperature. What is the Fe3+ concentration of the unknown solution?
Chemistry
1 answer:
posledela2 years ago
6 0

Answer:

Molar concentration of the Fe³⁺ in the unknown solution is 8.01x10⁻⁵M.

Explanation:

When you make a calibration curve in a spectrophotographic analysis you are applying the Lambert-Beer law that states the concentration of a compound is directely proportional to its absorbance:

A = E*l*C

<em>Where A is absorbance, E is molar absorption coefficient, l is optical path length and C is molar concentration</em>

<em />

Using the equation of the line you obtain:

y = 4541.6X + 0.0461

<em>Where Y is absorbance and X is concentration -We will assume concentration is given in molarity-</em>

As absorbance of the unknown is 0.410:

0.410 = 4541.6X + 0.0461

X = 8.01x10⁻⁵M

<h3>Molar concentration of the Fe³⁺ in the unknown solution is 8.01x10⁻⁵M.</h3>

<em />

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2 years ago
In the formula X2O5, the symbol X could represent an element in Group
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Answer: (3) 15

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2 years ago
PLS HELP! 50 PTS!
ioda

Answer:

The average kinetic energy of the gas particles is greater in container B because it has a higher temperature.

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By mistake, you added salt instead of sugar to the<br> oil. How can you remove the salt?
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Read 2 more answers
Consider the Williamson ether synthesis between 2-naphthol and 1-bromobutane in strong base. A reaction was performed in which 0
Lera25 [3.4K]

Answer:

0.70 g

41 %

Explanation:

We can write the Williamson ether synthesis in a general form as:

R-OH + R´-Br ⇒  R-O-R´

where R-OH is an alcohol and R´-Br is an alkyl bromide.

We then see that the reaction occurs in a 1:1 mole ratio to produce 1 mol product.

Therefore what we need to calculate the theoretical yield and percent yield is to compute the theoretical number of moles of   2-butoxynaphthalene produced from 0.51 g 2-naphthol, and from there we can calculate the percent yield.

molar mass  2-naphthol = 144.17 g/mol

moles 2-naphthol  = 0.51 g / 144.17 g/mol = 0.0035 mol 2-naphthol

The number of moles of  produced:

= 0.0035 mol 2-naphthol  x ( 1 mol 2-butoxynaphthalene /mol 2-naphthol )

= 0.0035 mol  2-butoxynaphthalene

The theoretical yield will be

= 0.0035 mol 2-butoxynaphthalene  x  molar mass 2-butoxynaphthalene

= 0.0035 mol x  200.28 g/ mol = 0.70 g

percent yield=  ( 0.29 g / 0.70 ) g  x 100 = 41 %

7 0
2 years ago
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