1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Lunna [17]
3 years ago
15

The concentration of Fe2 in a sample is determined by measuring the absorbance of its complex with ferroxine. The sample, measur

ed in a 1.00 cm cuvette, has an absorbance of 0.242 . The reagent blank in the same cuvette has an absorbance of 0.041. What would be the absorbance reading for each of these two solutions if measured in a 5.00 cm cuvette
Chemistry
1 answer:
sdas [7]3 years ago
8 0

Answer:

  • Absorbance of sample solution = 1.21
  • Absorbance of reagent blank = 0.205

Explanation:

In order to solve this problem we need to keep in mind the <em>Lambert-Beer law</em>, which states:

  • A = ε*b*C

Where ε is the molar absorption coefficient, b is the length of the cuvette, and C is the concentration.

By looking at the equation above we can see that if ε and C are constant; and b is 5 times higher (5.00 cm vs 1.00 cm) then the absorbance will be 5 times higher as well:

  • Absorbance of sample solution = 0.242 * 5 = 1.21
  • Absorbance of reagent blank = 0.041 * 5 = 0.205
You might be interested in
1. Unas de las formas de producir nitrógeno gaseoso (N2) es mediante la oxidación de metilamina (CH3NH2), tal como se muestra en
Maslowich

Answer:

a) 4CH₃NH₂ + 9O₂ ⇄  4CO₂ + 10H₂O + 2N₂    

b) m = 5,043 g

c) % = 69,4 %

Explanation:

a) La ecuación balanceada es la siguiente:

4CH₃NH₂ + 9O₂ ⇄  4CO₂ + 10H₂O + 2N₂              

En el balanceo, se tiene en la relación estequiométrica que 4 moles de metilamina reacciona con 9 moles de oxígeno para producir 4 moles de dióxido de carbono, 10 moles de agua y 2 moles de nitrógeno.  

b) Para determinar la masa de nitrógeno se debe calcular primero el reactivo limitante:

n_{O_{2}} = \frac{m}{M} = \frac{25,6 g}{31,99 g/mol} = 0,800 moles      

n_{CH_{3}NH_{2}} = \frac{4}{9}*0,800 moles = 0,356 moles

De la ecuación anterior se tiene que la cantidad de moles de metilamina necesaria para reaccionar con 0,800 moles de oxígeno es 0,356 moles, y la cantidad de moles iniciales de metilamina es 0,5 moles, por lo tanto el reactivo limitante es el oxígeno.

Ahora, podemos calcular la masa de nitrógeno producida:

n_{N_{2}} = \frac{2}{9}*n_{O_{2}} = \frac{2}{9}*0,8 moles = 0,18 moles

m_{N_{2}} = n_{N_{2}}*M = 0,18 moles*28,014 g/mol = 5,043 g

Por lo tanto, se pueden producir 5,043 g de nitrógeno.

c) El redimiento de la reacción se puede calcular usando la siguiente fórmula:

\% = \frac{R_{r}}{R_{T}}*100

<u>Donde</u>:

R_{r}: es el rendimiento real

R_{T}: es el rendimiento teórico

\% = \frac{3,5}{5,043}*100 = 69,4

Entonces, el procentaje de rendimiento de la reacción es 69,4%.

Espero que te sea de utilidad!        

5 0
3 years ago
Complete this example: A 0.67 molal solution was
Lynna [10]

Answer:

A then C

Explanation:

3 0
2 years ago
What transition energy corresponds to an absorption line at 527 nm?​
Ede4ka [16]

Answer:

E = 3.77×10⁻¹⁹ J

Explanation:

Given data:

Wavelength of absorption line = 527 nm (527×10⁻⁹m)

Energy of absorption line = ?

Solution:

Formula:

E = hc/λ

h = planck's constant = 6.63×10⁻³⁴ Js

c = speed of wave = 3×10⁸ m/s

by putting values,

E = 6.63×10⁻³⁴ Js ×  3×10⁸ m/s / 527×10⁻⁹m

E = 19.89×10⁻²⁶ Jm /527×10⁻⁹m

E = 0.0377×10⁻¹⁷ J

E = 3.77×10⁻¹⁹ J

4 0
3 years ago
Read 2 more answers
Match the following items. Match the items in the left column to the items in the right column. 1. general or nonspecific observ
ivann1987 [24]
when column B is like the attached pic: (missing in your question)

so the matches will be like that:

1- Qualitative :

as Qualitative is a general or nonspecific observation, they also don't require

measurements and even can't be measured, that is because of the reality is

being approximated only. It  describes qualities and uses opinion

2- Hypothesis : 

as a hypothesis is an educated guess quantitative, and it is a prediction stated

in " If and then " form. a hypothesis to be valid need a research such as:

-Encyclopedia & state and local research facilities & scientific journals.

3- Direct relationship:

as a Direct relationship is when two variable change in the same direction,

and one remaining larger than the other by the same factory.  

- this is a type of a relationship in which there is a change with one variable, and corresponding with the change in the other. and because this corresponding change with the other variable in the same direction so it refers to a positive relationship. 

4- Quantitative:

as Quantitative is a measured observation, It's an information or data based

on quantities obtained. And using numbers, equipment and standard units.

5- Control :

as control is standard, reference data or experiment qualitatively. this is what

you compare your experimental results to. This is for comparing results, it

used as a standard for comparison and use baseline measurements to use in

the comparing.

6- Theory :

 as Theory is a presently accepted explanation of how something happened.

 Scientifically acceptable general principles to explain phenomena. It the

general or abstract principles of the science. for example the  wave theory of

light.

7- Law :

as a law is a statement that explains what something does under the same

conditions. when we take about law in science, it is a general rule to explain

the observations in the form of a mathematical statement. Scientific law may 

be stated in words or expressed as a mathematical equations.

8- Best fit curve:

as best fit curve is a curve drawn to average the data's deviations direct

relationship. It is a process of constructing a curve that has best fit to a

series of data points. 

7 0
3 years ago
An aqueous solution contains 32.7% KCl (wt/wt%). what is the mole fraction of KCl in the solution
inna [77]

The mole fraction of KCl in the solution is 0.1051

calculation

mole fraction of KCl in solution = moles of KCl / total number of moles(moles of KCl +moles of H2O)

moles=mass/molar mass

mass of KCl=32.7g

molar mass of KCl= 39 +35.5

moles of KCl is therefore= 32.7g/74.5 g/mol=0.439 moles

find the moles of H2O= mass of H2O/molar mass

mass of H2O=100-32.7=67.3g

molar mass of H2O=( 1 x2) +16=18 g/mol

moles = 67.3/18 =3.739 moles

total moles=3.739+0.439=4.178 moles

mole fraction is therefore=0.439/4.178=0.1051

5 0
3 years ago
Other questions:
  • What is the molar mass of chcl3?
    10·1 answer
  • Complete the reactions to show how butanoic acid may be converted to butanal.
    9·1 answer
  • 3. Prolonged exposure to lead or lead salts is toxic. To prevent lead poisoning, the current standard for lead paint is 600.0 pp
    14·1 answer
  • How to find the relationship between slope and speed
    8·1 answer
  • Hi, i need help.. please
    14·1 answer
  • 12. Calculate the hydroxide ion concentration of a solution with pH = 10.25. Show all calculations leading to an answer.
    5·2 answers
  • Please help me answer Question 1.
    11·1 answer
  • Are humans more similar to trees or bacteria? How do you know?(1 point)
    10·1 answer
  • Suppose you have a 1:1:1 by weight mixture of three solid compounds, salicylic acid 4-nitroaniline naphthalene. You dissolve 1 g
    8·1 answer
  • Viết cấu hình electron nguyên tử và xác định vị trí của nguyên tố trong bảng tuần hoàn các nguyên tố hóa học nếu: a) n = 2; l =
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!