Oh goodness, I'm such a pain! I need some help with these! How do I calculate the percentage? How do I start it?
2. Imagine that you ran a similar titration using a different iron sample with 0.02 M KMnO4 as the titrant. Calculate the percent of iron in the sample if the sample weighed 0.67 grams, and the volume of the titrant used was 35.7 mL.
% of iron in sample:
3. Calculate the percent of iron in a 50.0 gram sample containing iron if 45.6 mL of 2.5 M KMnO4 titrant was used.
% of iron in sample:
4. Explain why an overshot endpoint is not a good titration.
The first two questions require me to look at some online interactive lab, but if I know how to do these, I'll be able to do those as well!
Thanks,
-Angel
#1.I presume this is titrating Fe(II) to Fe(III).
Write the equation and balance it.
KMnO4 + 5Fe^+2 ==> 5Fe^+3 + Mn+2
You should balance the remainder of the equation.
mols KMnO4 used = M x L = ??
Convert mols KMnO4 to mols Fe by using the coefficients in the balanced equation.
mols Fe = mols KMnO4 x (5 mols Fe^+2/1 mol KMnO4) = ??
Convert mols Fe to grams Fe.
grams = mols Fe x molar mass Fe.
Convert grams Fe to percent.
percent Fe in sample = [grams Fe/mass sample]*100
#2. Worked the same way.
#3. You had the same question last night and I told you to think about it. You WANT to stop at the exact equivalence point. What would undershooting or overshooting the equivalence point mean?
Thank you! Oh, question 4 is fine, I just accidentally copied it with the rest of the questions- it's repeated in this assignment too. Okay, I'll try and get this!
Explain Why an overshot endpoint is not a good titration.?
Calculate the percent of iron in a 50.0 gram sample containing iron if 45.6 mL of 2.5 M KMnO4 titrant was used. Could you help me with solving this question? I'm confused.
No problem, Angel! I'm here to help you out. Let's start with your first question about calculating percentages.
To calculate a percentage, you need two pieces of information: the part and the whole. The percentage is the part divided by the whole, multiplied by 100. In mathematical terms, this can be represented as:
Percentage = (Part / Whole) * 100
Now let's move on to your specific questions.
Question 2: To calculate the percent of iron in the sample, you need to determine the number of moles of iron and the number of moles of the titrant used. Then divide the moles of iron by the moles of the titrant and multiply by 100 to get the percentage.
Here are the steps:
1. Convert the volume of the titrant used (35.7 mL) to liters by dividing it by 1000.
2. Calculate the number of moles of the titrant (KMnO4) by multiplying its molarity (0.02 M) by the volume in liters.
3. Use the balanced chemical equation and stoichiometry to determine the moles of iron reacted based on the moles of KMnO4 used.
4. Divide the moles of iron by the initial mass of the sample (0.67 grams) and multiply by 100 to get the percentage of iron in the sample.
Question 3: Similar to the previous question, you need to calculate the number of moles of iron and the number of moles of the titrant used. Then, divide the moles of iron by the moles of the titrant and multiply by 100 to get the percentage.
Here are the steps:
1. Convert the volume of the titrant used (45.6 mL) to liters by dividing it by 1000.
2. Calculate the number of moles of the titrant (KMnO4) by multiplying its molarity (2.5 M) by the volume in liters.
3. Use the balanced chemical equation and stoichiometry to determine the moles of iron reacted based on the moles of KMnO4 used.
4. Divide the moles of iron by the initial mass of the sample (50.0 grams) and multiply by 100 to get the percentage of iron in the sample.
Now, let's move on to question 4 about overshot endpoint in titration.
An overshot endpoint in a titration occurs when you have added too much titrant, resulting in excess reactant reacting with the analyte. This overshooting of the endpoint can throw off the accuracy and precision of the titration results.
There are a few reasons why an overshot endpoint is not ideal:
1. Accuracy: The excess titrant can cause a shift in the equilibrium of the reaction, leading to inaccurate results. This can be particularly problematic if the reaction is sensitive to the concentration of the titrant.
2. Wasted resources: Adding more titrant than necessary means you are using excess chemicals, which can be a waste of resources in a laboratory setting.
3. Difficulty in detection: Overshooting the endpoint makes it challenging to identify the exact point where the reaction is complete. This can introduce uncertainty and make it harder to determine the concentration of the analyte accurately.
Overall, it's important to add the titrant carefully and precisely to reach the endpoint without overshooting it to obtain accurate and reliable results in a titration.
I hope this helps you understand the concepts and steps involved in calculating percentages and the reasons why an overshot endpoint is not ideal in titration. If you have any further questions, feel free to ask!