Question

Experiment 1: Titrations With Hot Taco Sauce and Ketchup

Materials: (2) 250 mL Beakers 100 mL Beaker (waste beaker) 30 mL Syringe Syringe stopcock 100 mL Graduated cylinder Funnel Stir rod Ring stand Ring Clamp pH meter	Scale 20 mL 0.1M NaOH 2 Ketchup packets 2 Hot sauce packets *90 mL Distilled water *Scissors *Computer Access *Access to a Graphing Software *Procedure for creating this solution provided in the "Before You Begin..." section (located at the beginning of the manual). * You must provide

Procedure

Part 1: Titration With Hot Taco Sauce

Place a clean 250 mL beaker on the scale. Tare out the beaker, and leave it on the scale.

Use scissors to carefully cut the corner of a taco sauce packet.

Squeeze out approximately1.5 g of sauce into the beaker. Record the exact mass of the sauce in Table 2.

Remove the beaker from the scale.

Use a graduated cylinder to measure and add 20 mL of distilled water to the beaker. Stir the solution well using a stir rod.

Set up the titration apparatus by first attaching the clamp to the ring stand. Remove the plunger from the syringe, screw on the stopcock to the bottom of syringe, and secure the syringe in the clamp. This set should be positioned high enough on the ring stand to fit a 250 mL beaker beneath it.

Pour approximately 20 mL of your sodium hydroxide solution into a new 250 mL beaker. Set the beaker aside.

Place a funnel on top of the syringe and a waste beaker (an extra 100 mL beaker) below it.

Make sure the syringe stopcock is open, and carefully rinse a few mL of sodium hydroxide through the syringe and let it drain into the waste beaker. Repeat this step so the syringe receives a total of two rinses. Return the 20 mL of the rinsed sodium hydroxide to the 250 mL beaker.

Close the syringe stopcock and begin filling the syringe with the sodium hydroxide solution. Fill the syringe to the point where the bottom of the meniscus touches the 20.0 mL mark. Check for air bubbles (especially in the syringe tip) and remove them if possible.

Hint: Fill the syringe slightly over the 20.0 mL mark and use a waste beaker to drain the syringe until the fluid volume is exactly on the 20.0 mL mark.

Keep the waste beaker below the syringe, and practice draining the syringe by slowly rotating the stopcock so that it is open. You will need a slow flow that you can start and stop approximately every 0.5 mL (the increments can be smaller than 0.5 mL for a more precise reading, but they should not be larger than 0.5 mL). Return all 20 mL of the NaOH to the syringe when you are confident with your titration technique.

Remove the cap from the end of the pH meter and rinse the probe with approximately 10 mL of distilled water. Turn the pH meter on by moving the switch at the top to the right. Place the pH meter into the beaker with the sauce solution, and record the initial pH in Table 3. This determines what the pH of the acid solution is when 0.0 mL of sodium hydroxide has been added.

Gently swirl the sauce solution (keeping the beaker on the counter), and slowly begin to add the sodium hydroxide to it by opening the stopcock. Do this very carefully because you will need to stop the flow and record the sauce solution’s pH every 0.5 mL. Record the pH measurements in Table 3.

Continue taking data measurements until the pH steadies. When this happens, close the stopcock and leave the remaining sodium hydroxide in the syringe for Part 2. At this time, complete the remaining data required for Table 2.

Graph your data by plotting the pH versus the amount of sodium hydroxide solution added. It is helpful to use a graphing software program for this step to achieve more precise data.

Determine the equivalence points from the graph and indicate them with horizontal lines. (See Figure 5 for reference).

Repeat Steps 1 - 16 to conduct a second trial of data, and record this data in Table 2 and 4, respectively.

Rinse out all of your used lab ware to prepare it for the next experiment.

Part 2: Titration With Ketchup

Place a clean 250 mL beaker on the scale. Tare out the beaker, and leave it on the scale.

Use scissors to carefully cut the corner of a ketchup packet.

Squeeze out 1.5 g of ketchup into the 250 mL beaker.

Record the exact mass of the ketchup in Table 5.

Use a 100 mL graduated cylinder to measure and pour add 20 mL of distilled water to the beaker. Stir the solution well using a stir rod.

Record the amount of sodium hydroxide that is still in the syringe from the hot sauce titration. This is the initial volume reading for the ketchup titration.

Remove the cap from the end of the pH meter and rinse the probe with approximately 10 mL of distilled water. Turn the pH meter on by moving the switch at the top to the right. Place the pH meter into the beaker of ketchup solution, and record the initial pH in Table 6. This determines what the pH is when 0.0 mL of sodium hydroxide has been added.

Gently swirl the ketchup solution (keeping the beaker on the counter), and slowly begin to add the sodium hydroxide solution to it by opening the stopcock. Do this very carefully because you will need to stop the flow and record the sauce solution’s pH every 0.5 mL. Record the pH measurements in Table 6.

Continue taking data measurements until the pH steadies. When this happens, close the stopcock.

Record the final syringe volume, and determine the total amount of sodium hydroxide used in the titration (final syringe reading-initial syringe reading). At this time, complete the remaining data required for Table 5.

Graph your data by plotting the pH versus the amount of sodium hydroxide solution added. It is helpful to use a graphing software program for this step to achieve more precise data.

Repeat Step 16 from Part 1.

Repeat Steps 1 - 12 to conduct a second trial of data, and record the data in Table 5 and 7, respectively.

Table 2: Hot Sauce Titration
	Hot Sauce Trial 1	Hot Sauce Trial 2
Mass of Sauce (grams)	1.5 grams	1.5 grams
Concentration of NaOH solution used	0.1 M	0.1 M
Volume of NaOH solution used to neutralize the sauce (found by locating the equivalence point on the titration graph)

Table 3: Hot Sauce pH Titration Data Trial 1
Amount of NaOH Added (mL)	Hot Sauce pH
0.0 mL	3.4
0.5 mL	3.5
1 ml	3.6
1.5 mL	3.8
2 mL	4.2
2.5 mL	4.3
3 mL	4.4
3.5 mL	4.6
4 mL	4.8
4.5 ml	4.9
5 mL	5.1
5.5 mL	5.3
6 mL	5.4
6.5 mL	5.9
7 mL	7.0
7.5 mL	7.3
8 mL	10.1
8.5 mL	10.6
9 mL	10.9
9.5 mL	10.9
10 mL	11.5
10.5 mL	11.7
11 mL	11.8
11.5 mL	11.8
12 mL	11.9
12.5 mL	11.9
13 mL	12
13.5 mL	12
14 mL	12
14.5mL	12.1

Table 4: Hot Sauce pH Titration Data Trial 2 Data Trial 1
Amount of NaOH Added (mL))	Hot Sauce pH
0.0	3.4
.5	3.5
1	3.9
1.5	4.0
2	4.1
2.5	4.2
3	4.4
3.5	4.6
4	4.7
4.5	4.8
5	4.8
5.5	5.0
6	5.1
6.5	5.1
7	5.2
7.5	6.9
8	7
8.5	7.1
9	7.2
9.5	7.5
10	7.7
10.5	8.6
11	9
11.5	10.3
12	11.1
12.5	11.2
13	11.2
13.5	11.2
14	11.3
14.5	11.6

Table 5: Ketchup Titration
	Ketchup Trial 1	Ketchup Trial 2
Mass of Sauce (grams)	1.5 grams	1.5 grams
Concentration of NaOH solution used	0.1 M	0.1 M
Volume of NaOH solution used to neutralize the sauce (found by finding the equivalence point on the titration graph)

Table 6: Ketchup pH Titration Data Trial 1
Amount of NaOH Added (mL)	Ketchup pH
0	3.8
.5	3.8
1	4.6
1.5	4.6
2	4.7
2.5	4.7
3	4.8
3.5	4.9
4	5
4.5	5.3
5	5.6
5.5	5.9
6	6.0
6.5	6.1
7	6.2
7.5	6.5
8	7
8.5	7.1
9	7.2
9.5	7.4
10	8
10.5	9.3
11	9.7
11.5	10
12	11.5
12.5	11.7
13	11.8
13.5	11.9
14	11.9
14.5	11.9

Table 7: Ketchup pH Titration Data Trial 2
Amount of NaOH Added (mL)	Ketchup pH
0	3.8
.5	3.9
1	4.2
1.5	4.6
2	4.8
2.5	4.9
3	4.9
3.5	5
4	5.1
4.5	5.2
5	5.5
5.5	5.8
6	6.1
6.5	6.2
7	6.3
7.5	6.6
8	7
8.5	7.1
9	7.2
9.5	7.5
10	8.1
10.5	8.8
11	9.3
11.5	9.8
12	10
12.5	11.2
13	11.6
13.5	11.8
14	11.9
14.5	11.9

Graph Your Data Here

Create the type of graph(s) which you think most clearly expresses the data. Be sure to include all trials, label the x and y-axes, and title the graph(s) accordingly. You may also use a graphing software program create your graphs.

Calculations

Determine the moles per gram of acetic acid in the hot sauce and ketchup in each trial.

Trial 1 (Hot Sauce):

Moles_acid =

             Moles_acid/gram =

Trial 2 (Hot Sauce):

Moles_acid =

             Moles_acid/gram =

Average of Trials 1 and 2 (Hot Sauce):

d. Trial 1 (Ketchup):

              Moles_acid =

               Moles_acid/gram =

Trial 2 (Ketchup):

Moles_acid =

             Moles_acid/gram =

Average of Trials 1 and 2 (Ketchup):

Answer 1

From the graphs:

pH of the equivalence point ~8, Volume of NaOH for the Sauce:

trial 1 ....7mL

trial 2.....10mL

Moles of acid:

trial 1..... 0.007L*0.1M=0.0007moles of acid

0.0007moles/1.5g=0.00047moles of acid/g

trial 2.... 0.01L*0.1M=0.001moles of acid

0.001moles/1.5g=0.00067moles of acid/g

Average

0.00057moles/g

KETCHUP

pH of the equivalence point ~8.1, Volume of NaOH for the Sauce:

trial 1 ....10mL

trial 2.....10mL

Moles of acid:

trial 1..... 0.01L*0.1M=0.001moles of acid

0.001moles/1.5g=0.00067moles of acid/g

trial 2.... 0.01L*0.1M=0.001moles of acid

0.001moles/1.5g=0.00067moles of acid/g

Average

0.00067moles/g