Name _______________________________

General Chemistry Virtual Lab: Titration Simulation

You will be performing a virtual titration as practice before our lab later this week. Go to the following website and then follow the set-up directions listed below. ***If you go to Mr. Trow’s webpage, this activity is hyperlinked already.

http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/stoichiometry/acid_base.html SETUP –

1. Select Type of Reaction: “STRONG ACIDS VS. STRONG BASE” 2. Fill the Burette with: “BASE” 3. Select the Acid and Base: “H2SO4” and “KOH” (You will need to click on the box to see the selections.) 4. Select the Indicator: “Phenolphthalein”

Before beginning the titration, collect or determine the following information…

Molarity of Acid (M): __________________

Volume of Acid (mL): __________________

Convert the Volume of Acid to Liters (L): __________________

PROCEDURE –

Your flask contains H2SO4 (an acid) and your burette contains KOH (a base). We will titrate the acid little by little until we see the color change from clear to pink. When the color changes for a second but then returns to colorless, we know we are getting close to the equivalence point. Continue titrating until the solution in the flask keeps its color without changing back to colorless. You have two options for adding more base into your flask:

1. Add drop by drop from the burette using the “DROPWISE” button. 2. Slide the bar on the right to add a larger amount of base at one time. Be careful though - you do not want to

overshoot your end point. If you go too far, you can start over by hitting “CONCORDANT VALUES.” Collect or determine the following data after your solution has changed color…

Total Volume of Base in mL: __________________

Convert the Volume of Base to L: __________________

*** Complete the calculations on the following page before you complete the rest of the simulation ***

CALCULATIONS – 1. From your data collected on page 1, fill in the following given values:

Molarity of Acid = ________________ Molarity of Base = ________________

Volume of Acid = ________________ Volume of Base = ________________

2. Calculate the number of moles of H2SO4 (acid) that were present in the flask: (show your work) 3. Write the chemical equation for this particular neutralization reaction below. Make sure the formulas are correct and that the equation is balanced.

________________ + ________________ ________________ + ________________

4. What is the molar ratio between H2SO4 and KOH? ____________

Using this ratio, how many moles of KOH must have been added to the flask? ______________ 5. Using the moles of base (#4) and the volume of base (#1), calculate the molarity of the KOH solution. 6. Type the molarity of your KOH solution into box #6 in the online window. Click “OK.” a) If your value was correct, the word “CORRECT” will appear below the box. Print this page and turn it in

with this lab. b) If your value is incorrect, you will have to double-check your calculations to find your error. You can then re-enter the correct value and follow step 6a.

7. Click on the “GRAPH” button – this will only appear if you solved for the correct molarity. On the grid to the right, draw an accurate sketch of what your titration curve looks like. Include: X-axis label and units

Sketch of the curve

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14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

pH