Procedure #1
PLEASE NOTE: Titration requires several steps in order to obtain exact results. The procedures described in this lab assume that you have already done the TITRATION TUTORIAL and are familiar with the technique.
1. Take a clean Erlenmeyer flask from the Glassware shelf and place it on the workbench.
2. Add 25 mL HCl (of unknown concentration) to the flask.
3. Add 2 drops of phenolphthalein to the flask.
4.Take a burrete from the Glassware shelf and place it on the workbench.
5. Fill the burette with 50 mL of 1M NaOH solution. Record this initial volume.
6. Drag the flask to the lower half of the burette so that the two will be connected.
7. Open the Data window and click on the flask. Click the Pushpin icon in the blue bar of the Data window to lock its display to the contents of the flask.
8. Open the Properties window and click on the burette. Enter "1" in the amount to add, and click the flow button to drip 1 mL of NaOH into the flask.
9. Continue to add NaOH in 1 mL increments.
10. The pink color will appear in flask all at once when the endpoint is either reached or crossed. Record the burette volume at which this occurs.
11. Detach the flask from the burette and drag it to the recycling chute.
Question #1 :
1. Write a balanced equation for the neutralization equation.
2. Use the two volumes obtained from your two trials of Procedure #2 to calculate the average volume of NaOH used to neutralize the HCl. Why is it not recommended to use the volume measured in Procedure #1 as part of this calculation?
3. Why was it necessary to repeat Procedure #2 and average the two volumes?
4. Use the average value calculated above and the molarity of the NaOH to calculate the molarity of the HCl.
4 answers
and i dot get how to do the calculations
NaOH + HCl --> NaCl + H2O
#4. mLNaOH x M NaOH = mL HCl x M HCl
Solve for the one unknown in the equation.
1 answer