1. Period 3/7 – Water discussion and pH notes
Tuesday, 10/2
Homework: Complete any overdue work
Agenda:
Period 2 – Nickel Lab
Period 3/7 – Water discussion and pH notes

2. The ATOM is the basic unit of matter.
ATOMS
The ATOM is the basic unit of matter.

3. The Subatomic Particles
LOCATION
CHARGE
Proton
Nucleus
Positive (+)
Electron
Outside the Nucleus
Negative (-)
Neutron
No Charge (0)
Nucleus
Electron

4. Elements Element is a pure substance made up of only one kind of atom*
An isotope of an element has a different number of neutrons

5. Most elements do not exist by themselves
Compounds
Most elements do not exist by themselves
Chemical Compound is a substance formed by the joining of two or more elements in definite proportions
e.g. H2O (WATER) or NaCl (TABLE SALT)
Chemical bonds hold the atoms in compounds together

6. Molecular Model Lab

7. Properties of water Water molecules (H2O) are neutral, yet charged!
The oxygen end has a slight negative charge
The hydrogen end has a slight positive charge
A water molecule is a polar molecule – an uneven distribution of charges between atoms in a molecule

8. Properties of water
Polar molecules can attract one another A hydrogen bond forms when the H atom on one water molecule is attracted to the O atom on another water molecule Cohesion is an attraction between molecules of the same Substance (Like the surface tension of water) Adhesion is an attraction between molecules of different Substances (Like when you get wet)

9. NICKLE LAB

10. Solutions Solution – all the components are evenly spread out
Water is the universal solvent (other liquids can be solvents too)
The substance dissolved is the solute
A water molecule can split to form a hydrogen ion (H+) and a hydroxide ion
(OH–).
An ion is a charged particle (either positive or negative)

11. pH Scale
The pH scale indicates the concentration of H+ ions in a solution
Ranges from 0-14
Water has a pH of 7

12. Acids
Produce hydrogen ions in solution pH less than 7 Important example is acid rain

13. Bases
Produce hydroxide ions in solution (OH-) pH greater than 7

14. The lower the pH the stronger the acid
The higher the pH the stronger the base
pH 7.0 is neutral

15. Neutralization reaction
Mixing an acid and a base will produce a salt and water.
The solution will become neutral (not acidic or basic)

16. pH LAB

17. Energy and Chemical Reactions
Living things undergo thousands of chemical reactions as part of the life process

18. A chemical reaction is a process that changes one set of chemicals into another set of chemicals
The elements or compounds that enter into the reaction are the reactants
The elements or compounds produced by the reaction are the products

19. Enzymes!

20. Some chemical reactions that make life possible are too slow …………
A CATALYST is a substance that speeds up the rate of a chemical reaction
Enzymes are PROTEINS that acts as biological catalysts
They speed up reactions that take place in cells
In an enzyme-catalyzed reaction, the reactants (known as substrates) bind to a site on the enzyme called an active site
The fit is so specific, like a lock and key, that only those substrates can bind with that enzyme

21. Digestion Reaction
Synthesis Reaction

22. Changes in temperature
Denaturing Enzymes
Denaturing an enzyme means that the shape has changed so it cannot fit it’s substrate anymore.
Things that can denature an enzyme:
Changes in temperature
Changes in pH

23. Enzyme animation: specificity, denaturing

24. Enzyme Pre-Lab

25. Potato contains an enzyme called CATALASE
FYI: Most enzyme names end with “ASE”

26. This enzyme turns HYDROGEN PEROXIDE (H2O2)into WATER (H2O) and OXYGEN (O2)

27. This is important because HYDROGEN PEROXIDE can damage cells
This is important because HYDROGEN PEROXIDE can damage cells. So the enzyme turns it into WATER before it does any harm

28. Like any enzyme, CATALASE can be DENATURED
Like any enzyme, CATALASE can be DENATURED. Things like temperature changes and pH changes can effect how well an enzyme works.

29. In Our Lab… The enzyme is CATALASE The substrate is HYDROGEN PEROXIDE
The product is WATER and OXYGEN
You will know the reaction is occurring by the FIZZING or BUBBLING