Neutralization of Acids
Part I Purpose: To determine number of drops of Na2CO3 sol’n it takes to neutralize a citric acid sol’n.
1) Use your graduated cylinder to add 5.0 mL of water to the cup labeled citric acid sol’n.
2) Add as much citric acid as you can pick up on the end of the toothpick to the water in the citric acid sol’n cup. Gently swirl until the citric acid dissolves.
3) Use your graduated cylinder to add 5.0 mL of water to the cup labeled sodium carbonate sol’n.
4) Add as much sodium carbonate as you can pick up on the end of a toothpick to the water in the sodium carbonate sol’n cup. Gently swirl until the sodium carbonate dissolves.
5) Add 5 drops of universal indicator to two wells in the well plate. Do not add anything else to the first well. This will be your control.
6) Add 2 drops of citric acid solution to the indicator in the second well and swirl to mix. If it is not reddish, add more drops. Record the number of drops of citric acid solution added.
7) Add single drops of sodium carbonate to the second well, swirling after each drop to mix, until the color looks like the control. Record the number of drops of sodium carbonate solution added.
8) Add two scoops of citric acid to the citric acid solution to increase the concentration. Gently swirl until the citric acid dissolves.
9) Add 5 drops universal indicator solution to a 3rd well in the well plate.
10) Add 2 drops of the more concentrated citric acid solution to the indicator and swirl to mix.
11) Add single drops of sodium carbonate to the 3rd well, swirling after each drop to mix, until the color looks like the control. Record the number of drops of sodium carbonate solution added. Clean well plate.
Drops Citric Acid / Drops Sodium Carbonate1st Citric Acid Solution
2nd Citric Acid Solution
Part II Purpose: To determine if Solution A or Solution B is more concentrated.
1) Add 5 drops universal indicator solution to three wells in a clean well plate.
2) Leave the first well alone so that it can be used as a control.
3) Add 2 drops of Solution A to the second well.
4) Add 2 drops of Solution B to the third well.
5) Neutralize Solution A using drops of the citric acid solution. Record the number of drops used.
6) Neutralize Solution B using drops of the citric acid solution. Record the number of drops used.
7) Clean up lab station.
Solution / Drops Solution / Drops Citric AcidA
B
Conclusion
1) The (1st /2nd) citric acid solution took more sodium carbonate to neutralize.
2) Why did it take more drops of sodium carbonate solution to neutralize it? ______
3) In part I, the solution becomes (more acidic/less acidic) as each drop of sodium carbonate.
4) What happens to the protons from the H3O+ ions when a base is used to neutralize an acid?______
5) [H3O+] is (greater than/less than/equal to) [OH-] in a neutral solution.
6) In Part II, is solution (A/B) the most concentrated? Explain.______
7) Antacids are medicines people take when the acid in their stomach is causing them discomfort. One advertisement claims the medicine provides relief for acid indigestion and sour stomach. What type of chemical do you think is in the medicine? ______Explain.______
Neutralization of Acids
Part I Purpose: To determine number of drops of Na2CO3 sol’n it takes to neutralize a citric acid sol’n.
1) Use your graduated cylinder to add 5.0 mL of water to the cup labeled citric acid sol’n.
2) Add as much citric acid as you can pick up on the end of the toothpick to the water in the citric acid sol’n cup. Gently swirl until the citric acid dissolves.
3) Use your graduated cylinder to add 5.0 mL of water to the cup labeled sodium carbonate sol’n.
4) Add as much sodium carbonate as you can pick up on the end of a toothpick to the water in the sodium carbonate sol’n cup. Gently swirl until the sodium carbonate dissolves.
5) Add 5 drops of universal indicator to two wells in the well plate. Do not add anything else to the first well. This will be your control.
6) Add 2 drops of citric acid solution to the indicator in the second well and swirl to mix. If it is not reddish, add more drops. Record the number of drops of citric acid solution added.
7) Add single drops of sodium carbonate to the second well, swirling after each drop to mix, until the color looks like the control. Record the number of drops of sodium carbonate solution added.
8) Add two scoops of citric acid to the citric acid solution to increase the concentration. Gently swirl until the citric acid dissolves.
9) Add 5 drops universal indicator solution to a 3rd well in the well plate.
10) Add 2 drops of the more concentrated citric acid solution to the indicator and swirl to mix.
11) Add single drops of sodium carbonate to the 3rd well, swirling after each drop to mix, until the color looks like the control. Record the number of drops of sodium carbonate solution added. Clean well plate.
Drops Citric Acid / Drops Sodium Carbonate1st Citric Acid Solution
2nd Citric Acid Solution
Part II Purpose: To determine if Solution A or Solution B is more concentrated.
1) Add 5 drops universal indicator solution to three wells in a clean well plate.
2) Leave the first well alone so that it can be used as a control.
3) Add 2 drops of Solution A to the second well.
4) Add 2 drops of Solution B to the third well.
5) Neutralize Solution A using drops of the citric acid solution. Record the number of drops used.
6) Neutralize Solution B using drops of the citric acid solution. Record the number of drops used.
7) Clean up lab station.
Solution / Drops Solution / Drops Citric AcidA
B
Conclusion
1) The (1st /2nd) citric acid solution took more sodium carbonate to neutralize.
2) Why did it take more drops of sodium carbonate solution to neutralize it? ______
3) In part I, the solution becomes (more acidic/less acidic) as each drop of sodium carbonate.
4) What happens to the protons from the H3O+ ions when a base is used to neutralize an acid?______
5) [H3O+] is (greater than/less than/equal to) [OH-] in a neutral solution.
6) In Part II, is solution (A/B) the most concentrated? Explain.______
7) Antacids are medicines people take when the acid in their stomach is causing them discomfort. One advertisement claims the medicine provides relief for acid indigestion and sour stomach. What type of chemical do you think is in the medicine? ______Explain.______