Lab Techniques
Materials and Methods
The laboratory procedures were conducted based on the steps provided in ‘An Introduction to Chemical Systems in the Laboratory’1. Specifically, 1.90 grams of KCL was weighed in a 250ml beaker and dissolved in 25 ml of deionized water. This solution was then quantitatively transferred to a 250ml volumetric flask. Proper technique is needed for quantitative analysis. This transfer was done to ensure that there was no detectable KCl left in the beaker. After transferring the solution add 3 drops of AgNO3 to the rinsed beaked to check the completeness of the transfer. Now take the volumetric flask and add deionized water till it is 6mm away from the etched mark on the neck of the flask. Place a stopper on the top of the flask and invert the flask to mix the solution and make it homogenous. Using a 25ml pipette, transfer 75ml of the solution into a new beaker.
Results
The empty 250ml beaker was determined to have a mass of 60.05 grams.
Table.1 Mass of Beaker and KCl on electronic balance
Empty Beaker (grams)
Beaker + KCl (grams)
KCl (grams) 60.05
61.95
1.90
The molarity of 1.90 grams of KCl dissolved in 25ml of deionized water was found to be 1.019 M.
= (1.90 g / 0.025 L) / 74.55 (g/ mol) = 1.019M
On adding 3 drops of AgNO3 solution the rinsed beaker no white precipitate was formed. The molarity of 1.9 grams of KCl dissolved in 250ml of deionized water was determined to be 0.102M
= (1.90 g / .25 L) / 74.55 (g/ mol) = 0.102 M
Error Analysis
No mathematical error analysis was needed. Discussion
This experiment was designed to acquaint one with the techniques of quantitative transfer, volumetric glassware and electric balances.
Carefully measure the weight of the 250ml beaker as well as KCl salt without the use of weighing paper or spatulas.
Add 25ml of deionized
The laboratory procedures were conducted based on the steps provided in ‘An Introduction to Chemical Systems in the Laboratory’1. Specifically, 1.90 grams of KCL was weighed in a 250ml beaker and dissolved in 25 ml of deionized water. This solution was then quantitatively transferred to a 250ml volumetric flask. Proper technique is needed for quantitative analysis. This transfer was done to ensure that there was no detectable KCl left in the beaker. After transferring the solution add 3 drops of AgNO3 to the rinsed beaked to check the completeness of the transfer. Now take the volumetric flask and add deionized water till it is 6mm away from the etched mark on the neck of the flask. Place a stopper on the top of the flask and invert the flask to mix the solution and make it homogenous. Using a 25ml pipette, transfer 75ml of the solution into a new beaker.
Results
The empty 250ml beaker was determined to have a mass of 60.05 grams.
Table.1 Mass of Beaker and KCl on electronic balance
Empty Beaker (grams)
Beaker + KCl (grams)
KCl (grams) 60.05
61.95
1.90
The molarity of 1.90 grams of KCl dissolved in 25ml of deionized water was found to be 1.019 M.
= (1.90 g / 0.025 L) / 74.55 (g/ mol) = 1.019M
On adding 3 drops of AgNO3 solution the rinsed beaker no white precipitate was formed. The molarity of 1.9 grams of KCl dissolved in 250ml of deionized water was determined to be 0.102M
= (1.90 g / .25 L) / 74.55 (g/ mol) = 0.102 M
Error Analysis
No mathematical error analysis was needed. Discussion
This experiment was designed to acquaint one with the techniques of quantitative transfer, volumetric glassware and electric balances.
Carefully measure the weight of the 250ml beaker as well as KCl salt without the use of weighing paper or spatulas.
Add 25ml of deionized