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
NeTakaya
3 years ago
11

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

lution had an absorbance of 0.480 . Fe3+(aq)+SCN−(aq)↽−−⇀FeSCN2+(aq) A trial solution was made in a similar manner, but with a more dilute Fe(NO3)3 reagent. The initial SCN− concentration, immediately after mixing, was 0.00050 M . This trial solution had absorbance of 0.220 . What is the equilibrium concentration of SCN− in the trial solution?
Chemistry
1 answer:
Xelga [282]3 years ago
5 0

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

You might be interested in
What do chemists think is the best measurement of concentration for describing the concentration of a solid solute dissolved in
lara31 [8.8K]

Answer:

Molarity.

Explanation:

  • The molarity (M) of a solution is defined as the no. of moles of solute that dissolved in 1.0 liter of the solution.

M = (mass / molar mass) of the solute (1000 / volume of the solution).

<em>So, the best measurement of concentration for describing the concentration of a solid solute dissolved in one liter of a liquid solution is Molarity.</em>

6 0
3 years ago
A graduated cylinder contains 18.0ml of water. what is the new water level after 35.6g of silver metal with a density of 10.5 g/
AlekseyPX

Answer:

The answer to your question is

1.- Volume = 3.4 ml

2.- Volume = 0.61 ml

3.- Mass = 2872.8 pounds

Explanation:

Problem 1

Volume = 18 ml

mass = 35.6 g

density = 10.5 g/ml

Process

1.- Calculate the volume of silver

Formula

density = \frac{mass}{volume}

solve for volume

volume = \frac{mass}{density}

Substitution

volume = \frac{35.6}{10.5}

<u>volume = 3.4 ml</u>

2.- Problem 2

Total volume = ?

Volume = 18 + 3.4

Volume = 21.4 ml

Data

mass = 8.3 g

density = 13.6 g(ml

volume = ?

Formula

density = \frac{mass}{volume}

Solve for volume

volume = \frac{mass}{density}

Substitution

volume = \frac{8.3}{13.6}

Result

<u>volume = 0.61 ml</u>

3.- Problem 3

Data

volume = 345 gal

density = 1 g/ml

mass = ?

Formula

density = \frac{mass}{volume}

Solve for mass

mass = density x volume

Covert gal to ml

                            1 gal --------------- 3785 ml

                         345 gal -------------  x

                            x = (345 x 3785) / 1

                            x = 1305825 ml

Substitution

mass = 1 x 1305825

mass = 1305825 g

Convert g to pounds

                        1 g ------------------- 0.0022 pounds

              1305825 g ----------------   x

                        x = (1305825 x 0.0022)

                       <u> x = 2872.8 pounds</u>

5 0
3 years ago
In order to calculate the number of neutrons you must subtract the what from the what?​
Katyanochek1 [597]

Answer:

You take the atomic, or proton number of the element, and you subtract it from the element's mass number.

6 0
3 years ago
Read 2 more answers
Writing the net ionic equation
vazorg [7]

First write the molecular equation with states:


(NH4)2S (aq) + 2AgNO3(aq) → Ag2S (s) + 2NH4NO3


Now write a full ionic equation by separating into ions all substances that dissociate: anything (s) (g) or (l) does not dissociate


2NH4 + (aq) + S 2-(aq) + 2Ag+ (aq) + 2NO3- (aq) → Ag2S(s) + 2NH4 + (aq) + 2NO3- (aq)


To write the NET IONIC equation, inspect the full ionic equation above and delete anything that appears on both sides of the → sign:


Net ionic equation:

S 2-(aq) + 2Ag + (aq) → Ag2S(s)

3 0
3 years ago
Read 2 more answers
What is 0.00000005 in scientific notation, rounded to two significant figures?
KIM [24]

Answer:

5×-10^8

That is the the scintific notation for 0.00000005

Answer=5×-10^8

7 0
3 years ago
Other questions:
  • How many atoms of lead are in 3.5 moles of lead?
    7·1 answer
  • Rocks and sand are nonliving .all organisms are
    10·1 answer
  • Molarity s defined as the
    10·2 answers
  • I am finding the formula of a compound that has 60% Carbon, 32% Oxygen, and 8% Hydrogen. Although, when it comes to actually cre
    10·1 answer
  • How many grams are 53.8 of oxygen
    14·1 answer
  • A class of substances known as __________ are used for their medicinal properties.
    9·2 answers
  • Dihydrogen sulfide reacts with oxygen gas to form sulfur dioxide and water. How many moles of oxygen gas will react when 0.6469
    15·1 answer
  • How many Joules are needed to raise 29.4g of aluminum from 32.0°C to 92.0°C? (The specific heat of aluminum is 0.900J/g °C)
    14·1 answer
  • What is the molar mass of CHCl3?<br> 48.47 g/mol<br> 83.92 g/mol<br> 119.37 g/mol<br> 121.39 g/mol
    5·2 answers
  • How many moles of Hydrogen gas will be produced if you start with 2.5 moles of Magnesium and an excess of Hydrochloric Acid give
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!