Chemistry Equilibrium Lab Question

In summary, the conversation is about a question regarding the calculations for an equilibrium lab, specifically involving the equation Fe3+ + SCN1- makes FeSCN2+. The person asking the question has the values for Fe3+ and SCN1- concentrations, and is wondering if they should simply add the two together to get the concentration of FeSCN2+. However, other participants in the conversation point out that this approach is not accurate and that more data is needed for accurate calculations.
  • #1
xoilovemeryl
2
0

Homework Statement



Hi! Okay so I have a question about the calculations for an equilibrium lab I completed. I have the equation

Fe3+ + SCN1- makes FeSCN2+

I know that Fe3+ equals 2.25x10 to the -5 power M and SCN1- equals 0.50 M.

. The attempt at a solution

Would I simply add the 2 together to get FeSCN2+? That seems too easy but it's all I can think of...thanks!
 
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  • #2
xoilovemeryl said:

Homework Statement



Hi! Okay so I have a question about the calculations for an equilibrium lab I completed. I have the equation

Fe3+ + SCN1- makes FeSCN2+

I know that Fe3+ equals 2.25x10 to the -5 power M and SCN1- equals 0.50 M.

. The attempt at a solution

Would I simply add the 2 together to get FeSCN2+? That seems too easy but it's all I can think of...thanks!
First of all assume you have 1 litre of sol'n
so you have 2.25x10^-5 mols of Fe3+ and 0.50 mols of SCN-
The Fe3+ is the limitting reagent so you can only get 2.25x10^-5 mols of FeSCN2+.
(Imagine you are making Ham and cheese sandwhiches. You have 20 pieces of cheese and 5 pieces of ham. You can only make 5 sandwhiches. Only instead of cheese it is SCN- and instead of Ham it is Fe3+)
So you have 2.25x10^-5 mols of FeSCN2+ and we assumed we had 1 litre of Fe3+ sol'n and 1 litre of SCN- sol'n. So when we put them together we had 2 litres of sol'n
so the concentration of FeSCN2+ = 2.25x10^-5 mols/2 litres
 
  • #3
Iodine said:
so the concentration of FeSCN2+ = 2.25x10^-5 mols/2 litres

That would mean concentration of Fe3+ is zero and stability constant is infinite. So it is not a correct approach.

xoilovemeryl: data you have listed so far is not enough to calculate concentration, it can be only approximated using stoichiometry (as Iodine did), but the value obtained is not the real one. I suppose you had more data to use in your calculations.

--
 
  • #4
This was a lab, so just as Borek said, you cannot just assume 1L of each. What if he used 1L of Iron and 10mL of SCN?
 
  • #5


Hi there!

In order to calculate the concentration of FeSCN2+, you will need to use the equilibrium constant (Kc) for the reaction. This constant is determined by the ratio of the concentrations of the products to the concentrations of the reactants at equilibrium. In this case, the equation for Kc would be:

Kc = [FeSCN2+]/[Fe3+][SCN1-]

To solve for [FeSCN2+], you will need to rearrange the equation to isolate this variable. It would look like this:

[FeSCN2+] = Kc x [Fe3+][SCN1-]

Now, you can plug in the given concentrations for Fe3+ and SCN1- and the calculated value of Kc to solve for [FeSCN2+]. Remember to use the correct units and to check your significant figures.

I hope this helps! Let me know if you have any further questions.
 

1. What is the purpose of a Chemistry Equilibrium Lab?

The purpose of a Chemistry Equilibrium Lab is to study the concept of chemical equilibrium, which is the state in which the forward and reverse reactions of a chemical reaction occur at equal rates. This lab allows students to observe and manipulate various factors that affect equilibrium, such as concentration, temperature, and pressure, in order to better understand this fundamental concept in chemistry.

2. How is equilibrium achieved in a chemical reaction?

Equilibrium is achieved in a chemical reaction when the rates of the forward and reverse reactions are equal. This means that the amount of reactants and products in the system remain constant over time, with no net change occurring. In order to achieve equilibrium, the reaction must take place in a closed system and the temperature, pressure, and concentration of the reactants must be constant.

3. What factors can affect the equilibrium of a chemical reaction?

The equilibrium of a chemical reaction can be affected by several factors, including temperature, pressure, and concentration. Changes in any of these factors can shift the equilibrium either to the left or to the right, altering the amounts of reactants and products in the system. Additionally, the presence of a catalyst can also affect the equilibrium by increasing the rate of the forward or reverse reaction.

4. How can Le Chatelier's Principle be applied to a Chemistry Equilibrium Lab?

Le Chatelier's Principle states that when a system at equilibrium is subjected to a stress, the system will respond by shifting in the direction that reduces the effect of that stress. In a Chemistry Equilibrium Lab, this principle can be applied by manipulating the factors that affect equilibrium, such as changing the temperature or concentration of the reactants, and observing how the system responds.

5. What are some real-life applications of chemical equilibrium?

Chemical equilibrium has many real-life applications, including in the production of commercial products such as fertilizers, pharmaceuticals, and industrial chemicals. It is also important in environmental processes, such as the equilibrium between carbon dioxide and bicarbonate in the ocean, and in biological processes, such as the equilibrium between oxygen and hemoglobin in the blood. Understanding and manipulating chemical equilibrium is crucial in many fields, including chemistry, biology, and environmental science.

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