1. Warm-up 2/16/16: Turn in Macromolecules Food lab Worksheet to the folder at your station. DO NOT TOUCH LAB MATERIALS!!!! Write the question and the correct answer to the question on your warm-up sheet for the week A student performed a food test on her lunch. The Iodine test and Brown paper bag test came back positive. What organic molecules were in her lunch? A.Starches only B.Sugars and starches C.Starches and lipids D.Lipids and sugars

2. Announcements Unit 2 Qualifier due TOMORROW!!! Unit 2 Quiz TOMORROW!!! Unit 2 Test THURSDAY!!!

3. Unit 1 Item Analysis Now we will complete the UNIT 1 Item Analysis and Track your UNIT 1 Assessment data. Please follow my instructions on how to use the data tracker.

4. What is pH?

5. Some of our favorite foods make our tongue curl up because they are SOUR. Acids and Bases Some foods have a “bite” of their own because they’re somewhat bitter. WHY? Bitter!

6. Acidic/Basic There is a scientific reason for this: These foods are either acidic or basic. Other substances besides foods have these characteristics. Chemicals may be classed as acids or bases. Things that are neither acids nor bases are neutral. pH measures how acidic or basic a solution is.

7. Acids Often taste sour Strong acids can burn skin & eyes Strong acids can dissolve metals Examples: Lemon juice Vinegar Car battery acid (dangerous!)

8. Bases Can taste bitter, sweetish, or salty Strong bases can burn skin & eyes Bases react more easily with protein than with metal; they are often used for cleaning Examples: Milk Baking soda Soap Drain cleaner (dangerous!)

9. pH A special name is given to the acid or base characteristic that a substance has: It is called: pH “p” stands for potential and “H” stands for hydrogen; hence, the potential of a substance to attract hydrogen ions

10. How Do We Measure pH? We measure pH by using special strips of paper called pH paper

11. How Does It Work? The paper is treated with chemicals that change color to show the pH. When the paper touches the substance being tested, it turns a specific color to tell if the substance is an acid or a base.

12. Acid Any substance which has a pH of value of less than 7 is considered an acid 0--------------7---------------14 Acid Neutral Base

13. Base Any substance which has pH value greater than 7 is a base 0--------------7---------------14 Acid Neutral Base

14. pH 7 A pH of 7 is called neutral—neither acid nor base. 0------------7------------14 Acid Neutral Base

15. The pH Scale

16. Why is pH important? Soil has to be in a certain pH range for plants to grow and stay healthy. Fish can’t live if the pH is too high or too low

17. pH and People Water that has too high or low pH contains harmful dissolved chemicals. Water plant operators keep a careful watch on the pH of our drinking water, to keep it safe.

18. pH pH scale  indicates H+ concentration 0-14 Acidic = 0-6 (lots of H+) Basic = 8-14 (little H+) Neutral = 7 (water)

19. pH Lab 1 3 8 6 4 2 7 5 9 10 waterSoda Milk Lemon Juice Vinegar X X X XX X X