Chapter 7: Unknown Calculation | CHM 214 | 064
TLDRThe video script describes a chemical analysis process for determining the calcium content in a urine sample. It outlines the procedure of precipitating calcium with oxalate, redissolving it, and then titrating with standard permanganate. The endpoint is reached using 16.17 milliliters of the standard solution. By applying stoichiometry and converting the results to moles, the script calculates the concentration of calcium in the urine sample. The final concentration is determined to be 0.00711 moles per liter, highlighting the importance of accurate analytical chemistry calculations.
Takeaways
- 🧪 The process involves analyzing an unknown urine sample to determine its calcium content using standardized manganese.
- 🥃 Calcium in the urine sample was precipitated with oxalate as demonstrated in a previous video.
- 🔄 The precipitate was redissolved, and the oxalate was titrated with standard permanganate.
- 📊 It took 16.17 milliliters of standard permanganate to reach the endpoint of the titration.
- 🧬 The concentration of the permanganate solution was given as 8.79 x 10^-4 moles per liter.
- 📈 The volume of permanganate used was converted to moles considering the concentration and volume units.
- 🌟 The stoichiometry of the reaction was accounted for, with a 5:2 molar ratio of oxalate to permanganate.
- 🤔 The number of moles of oxalate is equal to the number of moles of calcium due to the 1:1 ratio in the precipitation reaction.
- 🧴 The concentration of calcium in the urine sample was calculated by dividing the moles of calcium by the volume of the sample.
- 📐 The final concentration was determined to be 0.00711 moles per liter, with three significant figures.
- 📝 The calculation is an example of the importance of stoichiometry and accurate measurement in analytical chemistry.
Q & A
What was the volume of urine sample used in the analysis?
-The volume of the urine sample used in the analysis was five milliliters.
How was calcium precipitated from the urine sample?
-Calcium was precipitated from the urine sample using oxalate according to the procedure shown in the last video.
What was the role of permanganate in this analysis?
-Permanganate was used to titrate the precipitate of oxalate that had redissolved, in order to determine the amount of calcium in the sample.
How much standard permanganate was required to reach the endpoint in the titration?
-It required 16.17 milliliters of the standard permanganate to reach the endpoint in the titration.
What was the concentration of the standard permanganate solution used?
-The concentration of the standard permanganate solution was 8.7 nine four seven moles per liter times ten to the minus four moles per liter.
How were the milliliters of permanganate converted to moles?
-The milliliters of permanganate were converted to moles by multiplying the volume (in milliliters) by the concentration (in moles per liter) and adjusting for the volume difference (1 liter = 1000 milliliters).
What is the stoichiometry between oxalate and permanganate as mentioned in the script?
-The stoichiometry between oxalate and permanganate is such that for every 5 moles of oxalate, 2 moles of permanganate react with it.
What was the calculated amount of oxalate in moles based on the titration results?
-The calculated amount of oxalate in moles was 0.03553 millimoles.
How is the amount of calcium related to the amount of oxalate in the sample?
-The amount of calcium is related to the amount of oxalate in the sample on a one-to-one ratio, as they precipitate together.
What is the concentration of calcium in the urine sample?
-The concentration of calcium in the urine sample is 0.00711 moles per liter (or millimoles per milliliter).
How many significant figures were retained in the final concentration of calcium?
-The final concentration of calcium retained three significant figures.
What is the importance of maintaining correct stoichiometry in analytical chemistry calculations?
-Maintaining correct stoichiometry in analytical chemistry calculations is crucial for accurately determining the amounts of substances involved in a reaction, ensuring the precision and reliability of the results.
Outlines
🧪 Analyzing Urine Sample for Calcium Content
The paragraph describes a chemical analysis process to determine the calcium content in an unknown urine sample. The process involves precipitating calcium with oxalate, redissolving it, and then titrating with standardized permanganate. The endpoint is reached using 16.17 milliliters of the standard permanganate solution. The goal is to calculate the concentration of calcium in the urine sample by converting the volume of permanganate used to moles, considering the stoichiometry of the reaction, and dividing by the volume of the urine sample. The final concentration of calcium is found to be 0.00711 moles per liter, with three significant figures.
Mindmap
Keywords
💡Urine sample
💡Calcium content
💡Oxalate
💡Permanganate
💡Titration
💡Stoichiometry
💡Concentration
💡Molarity
💡Endpoint
💡Significant figures
Highlights
The process involves analyzing an unknown sample of urine to determine its calcium content.
Calcium in the urine sample is precipitated with oxalate as per the procedure shown in the last video.
The precipitate is then redissolved, and the oxalate is titrated with standard permanganate.
The concentration of the standard permanganate used is noted, which is crucial for the calculation.
It took 16.17 milliliters of the standard permanganate to reach the endpoint of the titration.
The goal is to calculate the concentration of calcium in the urine based on the titration results.
The calculation starts by converting the volume of permanganate used to moles.
The concentration of permanganate is given as 8.7 nine four seven moles per liter times ten minus four.
The conversion from milliliters to liters is necessary to find the moles of permanganate.
The calculation yields 1.422 times 10 to the minus 5 moles of permanganate.
Stoichiometry is considered, with a 5:2 molar ratio of oxalate to permanganate.
This leads to 0.03553 millimoles of calcium oxalate (CaC2O4) being present.
Since the calcium and oxalate precipitate in a 1:1 ratio, the moles of oxalate equal the moles of calcium.
The concentration of calcium in the urine sample is found by dividing the moles of calcium oxalate by the volume of the urine sample.
The final concentration is calculated as 0.00711 moles per liter.
The importance of tracking moles and maintaining correct stoichiometry in analytical chemistry is emphasized.
The process is an example of bookkeeping in chemistry, ensuring accurate mole tracking and stoichiometric calculations.
The method can be applied to various analytical chemistry scenarios for accurate substance quantification.
The practical application of this process is in determining the concentration of specific substances in biological samples.
The process demonstrates the use of titration as a technique for quantitative analysis in chemistry.
The transcript provides a step-by-step guide for analyzing and calculating the concentration of a substance in a sample.
Transcripts
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