CHEM 1LD Study Guide - Final Guide: Volumetric Flask, Intermolecular Force, Molar Mass

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ochreraven97

6 Sep 2017

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Document Summary

Density of mixture in the 10 ml vol flask mass of mixture in the. Calculate the percent change in volume for the mixture. As forces increase the volume decreases making the change in volume negative. Which means the more force pull and attract each other the lesser the volume will be. H/r is the slope if you look a it in a y=mx+b so to find h get the slope using y2- y2/x2-x1 for two points then you will divide by the r constant. Multiply the top reaction by 2 and the bottom one by 5 to make the number of electrons gained and lost the same. Other question: balanced equation for iron salt show half reactions. 2 fe(nh4)2(so4)2 6h2o + _3__ h2c2o4 + _3_ k2c2o4 + _1_ h2o2 __2_ k3fe(c2o4)3 3h2o + 4 spots measure from origin to the spot then from the origin to the top solvent line .

Related Questions

Determinatrion of Iron in Vitamin

A. Prep of Iron Soln. from Vitamin

Weigh three vitamin tablets and place each tablet in separate 125-mL Erlenmeyer Flask. Add 25 mL of 2M HCL to each flask in the hood and boil the samples for 15 mins.

Set up Vacumm filter system and filter each sample serparetely and collect the filtrate(liquid). Transfer filtrate after each run to a 50 mL Volumetric flask. Rinse filter flask with DI water and transfer rinse to the vol. flask as well. Repeat for each solution.

After solutions cool, dilute it to the mark with DI water and Mix well. Transfer contents to a labeled beaker.

For each solution made, transfer 1.00 mL of the solution with a volumetric pipette and place it in a fresh 50 mL vol. flask. Then dilute it ot he mark with DI water.

B. Prep of sample Solutions

From each diluted vitamin solution a test solution sample will be made. Using a vol. pipette transfer 5.00 mL of the diluted vitamin solution(unknown molarity) to a large test tube. Then add 4.00 mL hydroquinone and 6 mL of o-phenanthroline to the test tube with a vol.pipettes. Note the volume of the test solutions. This dilution step is needed when calculate the mass of iron in the tablets.

C. Prep of Sample Solutions

One iron standard solution will be made for the class.

D. Prep of Calibration Solutions

Each student pair will make at least one calibration solution. Have the instructor assign you a solution 0-7. The entire lab section will make one calibration set by the following steps:

Label a 50.00 mL vol. flask with your assigned number (0-7)

Collect ~ 5 mL of hydroquinone and transfer it to a clean beaker. Then collect ~ 5 mL of phenathroline and transfer this solution to another clean beaker. Transfer 2.00mL of hydroquinone and 3.00mL of phenathroline using vol. pipettes to the labeled vol. flask

Collect ~5-10 mL of the standard solution and transfer it to a clean beaker. The amount of iron solution to transfer via vol. flask is equal to the assigned number (i.e. if your group was assigned #1, transfer 1.00 mL of the iron solution to the flask. Flask 0 will not contain any iron solution.

Once all three reagents have been added to a flask. Add ~ 20mL of DI water. Mix the solution by capping the flask and inverting it several times. Continue adding DI water to the mark on the flask and mix solution again by inversion.

What is the molarity of the iron in each calibration solution?

Given Info/Data


Mass of Iron in Tablet from bottle (mg)	18
Mass of Iron for Stock Soln. (g)	0.1435
Molar Mass of Fe(NH₄)₂(SO₄)2â¢ 6H₂O (g/mol)	392.14
Molar Mass of Fe (g/mol)	55.845
Moles of Iron Stock Solution (mol)	0.000365941