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Unit 10 Acids and Bases

Unit 10 Acids and Bases. Wed/Thurs May 21 st/ 22nd, 2014. You need: Notes notebook, molarity/dilution worksheet out to be checked for credit, pen/pencil QOTD. Do it in your notebook. A. List at least five things that come to mind when you hear the word acid.

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Unit 10 Acids and Bases

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  1. Unit 10 Acids and Bases

  2. Wed/Thurs May 21st/ 22nd, 2014 You need: Notes notebook, molarity/dilution worksheet out to be checked for credit, pen/pencil QOTD. Do it in your notebook. A. List at least five things that come to mind when you hear the word acid. B. List at least five things that come to mind when you hear the word base (in a chemistry class). C. How are acids and bases related to each other?

  3. Housekeeping HW- Pre-lab for Acid-Base Titration lab Word document and PDF that contains notes for lab- DUE 5/28 and 5/29 ****if you do not have your pre-lab you will not get to complete the lab****** 5/27- Sub 5/28 and 5/29 (LAB PANTS!!!!!!)

  4. Water does behave like an ionic compound, ever so slightly. Out of 1,000 grams of water, about 0.0000018 grams will act like an ionic compound and dissociate into ions. What ions would be formed when a water molecule breaks down? H+ and OH- ions are formed when water dissociates. 1 mole of water is 18 grams, so 0.0000018 grams of water is 10-7moles of water.

  5. So, in 1,000 grams of water, which is 1 liter of water, 10-7 moles of water will dissociate into H+ ions and OH- ions. This means you will have 10-7 moles of H+ ions and 10-7 moles of OH- ions. • We can say that the concentration of H+ ions in normal water is 10-7 moles per liter. • This is written this way: [H+] = 10-7 • The base 10 logarithm of 10-7 is -7. • So, in normal water, log[H+] = -7.

  6. Even in the most acidic solutions, [H+] is usually a very small number, which means the log is usually negative. For this reason, we have chosen to use a scale to measure [H+] that eliminates the negative sign. • This scale is the pH scale, which reflects the concentration of H+ ions in a solution. • It is defined as follows: pH = -log [H+] • In normal water, [H+] = 10-7 • So, in normal water, log [H+] = -7 • So, in normal water, -log[H+] = 7, which means pH = 7 • This is why the pH of normal water is 7.

  7. Wed/Thurs May 28th/29th 2014 • You need: Notes notebook, pen/pencil and acids/bases pre-lab You have a lab today- PANTS!!!!!!! QOTD After being introduced to acids and bases- what can you say about the relationship between an acid and a base *****answer this in full sentences

  8. Housekeeping HW tonight- practice with pH worksheet Tuesday June 3rd- acids and bases QUIZ Friday June 5th- Acids and Bases Exam (scoring guide tomorrow)

  9. Suppose that you had 10 times as many H+ ions as there are in normal water. In other words suppose that your solution was 10 times more acidic than normal water. • (Because acids all have H+ ions, being acidic means you have more H+ ions than normal.) • 10 times the normal concentration means [H+] = 10-6 (instead of the 10-7 you have with normal water). • So, log [H+] = -6 and -log[H+] = 6 = pH. • This is why numbers below 7 mean an acidic solution, and numbers above 7 mean a basic solution.

  10. How can you increase the pH of a solution? • Increasing the pH means decreasing the number of H+ ions. You can do that by adding something that includes OH- ions (a base), because the OH- ions will bond with the H+ ions to make water. This will reduce the number of H+ ions that are loose in the solution.

  11. A. What does a low value on the pH scale mean? B. What does it mean to say that a solution is basic? C. Why is pH important? D. Write a balanced chemical equation for the reaction of hydrochloric acid and sodium hydroxide. Identify the type of reaction. Sum up the products in two words.

  12. LAB NOTES • Groups of 4 • Trade off doing titrations • Three trials!!!!!!!! • Reading the buret • Put paper under the beaker 4. “Dropping” base

  13. Today- LAB • Lab rotation- if you are not in lab- you are working on the pH balancing worksheet

  14. Friday May 30th, 2014 You need: Notes notes notebook, pen/pencil and practice with pH worksheet QOTD In your own words, describe the pH scale. What does it measure? Why is 7 such an important value? What do low and high values mean? Predict what it means to "neutralize" an acid? What product(s) is formed every time there is a neutralization?

  15. BONUS QOTD In the heating curve shown below, the parts of the curve where temperature remains constant represents? a. when particles move faster                              b. when kinetic energy of particles decreasesc. when heat is no longer added                          d. when a phase change is occurring.

  16. Housekeeping • HW- acid/base reaction worksheet and Titration calculations (same worksheet) • Tuesday June 3rd- acids and bases QUIZ • Friday June 6th- Acids and Bases Exam (scoring guide today) • LAB Report DUE Friday June 6th, 2014

  17. LAB INFO • WHAT DO You NEED? • HOW to do calculations • Common problems • Analysis • Organization • Pronoun usage

  18. An acid and base neutralize each other in a double displacement reaction in which the hydrogen ions from the acid combine with the hydroxide ions from the base to form water. • The other product is called a salt. A salt is an ionic compound that can be formed as the product of an acid-base reaction. • So, in an acid-base reaction, an acid reacts with a base to form water and a salt.

  19. Write a balanced equation for the neutralization of sulfuric acid with calcium hydroxide. Identify the acid, the base, and the salt by name and formula.

  20. In class work…….and homework Acid Base and Titration Worksheet

  21. Monday June 2nd, 2014 You need: notes notebook, pen/pencil, practice with pH worksheet, titration calculation worksheet, acid-base reaction worksheet

  22. Housekeeping HW tonight- pH calculation worksheet QUIZ 6/3/2014 EXAM Friday 6/6/14 TODAY- review HW sheets

  23. pH Calculations Formula for calculating pH- pH= - log[H+] Examples: Given that pH= 10.7, what is the concentration of H+ ? ----HOW DO WE SOLVE THIS?????

  24. pH Calculations • What is the pH of 0.15M HBr? -strong acid- means it totally ionizes 2. pH= 13.6 what is the concentration of H+ 3. pH of 3.67 x 10-7 M HI 4. pH= 7.7 what’s the concentration of H+ ?

  25. pOH calculations Remember that [H+]= [OH-] for normal water…. What do the molarities of these dissociated species add up to? Calculate the pH of a solution that has a concentration of [OH-] at 7.69 x 10-3 M.

  26. Tuesday June 3rd, 2014 You need: Notes notebbok, pen/pencil, pH calculations worksheet You have a quiz today. Pick one up from me before you sit down.

  27. Housekeeping HW tonight- print out review packet from the website Exam Friday June 6th Due Friday- review packet LAB REPORT DUE ----change to MONDAY JUNE 9th, 2014.

  28. PRACTICE • A. Nitric acid is neutralized by calcium hydroxide solution. Write a balanced chemical equation for the reaction, and name the salt that is formed. • B. Iron (III) sulfate is produced in an acid-base reaction. Write a balanced chemical equation for the reaction, and name the acid and the base. • C. You have 3 L of 4 M HCl. You add 6 L of water. Calculate the new concentration.

  29. QOTD You have 600 mL of 2.5 M KCl solution. You add 350 mL of water. What is the final concentration?

  30. Period 4 Groups 1- Hannah, Abby, Maggie H., Francis 2- Mary, Alexis, Sam, Kevin 3- Julie, Trevon, Jerome, Maggie S. 4- Francis, Grif, Jeshsie, Alex 5- Marcel, Marissa, Ian, Drew 6- Noah, Megha, Riley, Essence 7- Jessica, Rezhaun, Christian, Vincent 8- Jack, Joe, Jennifer 9- Katie, Mackenzie

  31. Period 6 1- Elle, Ryan, Elizabeth, Lauren, Jacob 2- Allise, Josh, Luke, Blayke 3- Chae Yeon, Maisy, Sophie, Brendan 4- Luis, Brooke, Connor, ZeJun 5- Roger, Julia, Michael, Haley 6- Julia C., Ciara, Moe, Quinn 7-Cameron, Jojo, Charlotte, Linda

  32. Wed/Thurs June 4th/5th 2014 You need: Review packet and pH calculations worksheet out to be stamped for credit. Sit quietly- for the demo 

  33. Friday June 6th, 2014 EXAM TODAY Backpacks need to be underneath your desk. Turn in your review packet on the demonstration desk (by the sink) Pick up an exam and a crib sheet.

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