Monday Nov 17 th -Week 15
TOPIC: Water and Solutions
Science of Life
 OBJ : 9-11
DO NOW : Draw a water molecule. Show all bonds using Bohr Models
EXT:
DW: Solute Worksheet
DUE DATE:
-----------------------------------------------------------------------------------------------------------------
-Objectives Check
-Binder Organization
-6.3 Notes
-Worksheet
HANDOUTS to PICK-UP:
-6.3 Notes
-6.3 Solute/Solvent Handout
SEMINAR 2:
-Quiz for 6.1 & 6.2
BEFORE/AFTER SCHOOL:
 DW-None
EXIT : Fill in your level of understanding DISTINGUISH between solutions and suspensions.

Monday: ___ 11 __/__ 17 ___
OBJECTIVE…  #_ 9-11 _____
TOPIC:
Water and Solutions
Daily Work GradeNone
DW GRADE:
 2  1  0
• Q: Draw a water molecule. Show all bonds using Bohr Models
• A:

Today’s Objectives
9  -- IDENTIFY how the properties of water make it well suited to help maintain homeostasis in an organism
10  --DETERMINE pH of various substances and DESCRIBE the use of the pH scale
11  --COMPARE / CONTRAST acids and bases and DESCRIBE how buffers affect cells.






H

6.3 WATER & SOLUTIONS
 WHAT YOU WILL LEARN
-about properties of water
-water’s polarity
-how acids differ from bases
 revhomeostasis
 MAIN IDEA:
Properties of water help organisms maintain homeostasis

 WATER’s PROPERTIES
water vital to life on earth
-properties
-provide environments suitable for life
-help maintain homeostasis
-book pic P162
-UNIVERSAL SOLVENT: separate the ions
-many substances dissolve in water
-ADHESIVE: attraction with other surfaces
-COHESIVE: attracted to each other [hold liquid together]
-POLAR: slight (+) / slight (-)
 Visualizing Properties of Water

 WATER’s POLARITY
POLARITY:
property of having 2 OPPOSITE poles/ends
A
R
R
DRAW a lewis structure of 2 HYDROGEN and OXYGEN atoms
O
H H
 IDENTIFY
COVALENT
2

 WATER’s POLARITY
 How many water molecules shown?______
5
HYDROGEN BOND:
weak interaction involving H ( flourine, oxygen, nitrogen)

 WATER’s POLARITY/ reasons/effects
electrons more strongly attracted to O nucleus than H nucleus
-causes bent shape

 MIXTURES w/ WATER
What is a mixture?
-A combination of 2 or more substances
-Each retains individual characteristics or properties ex: tossed salad, mixed bag of M&Ms, Salt Water
2 Different Types:
Homogenous -uniform composition throughout ex: crystal light
Heterogenous -components remain distinct ex: Salad solution

 MIXTURES w/ WATER
SOLUTION-
another name for HOMOgenous mixture
SOLVENT-
SUBSTANCE in which ANOTHER is DISSOLVED
SOLUTE-
SUBSTANCE that IS DISSOLVED solution
 IDENTIFY the property of water that makes it a good SOLVENT-
-POLARITY

DEMO

 ACIDS/BASES/pH
ACIDS
 increase in hydrogen ions
-a solution that has an excess of H + ions
HYDROGEN IONS-
positively charged ion of hydrogen H +
BASES
 decrease in hydrogen ions
-a solutions that has an excess of OH ions
HYDROXYL IONS-
negatively charged ion of hydroxide OH -

 Acids & Bases Examples

 ACIDS/BASES/pH release MANY H +
WATER release FEW H + release FEW OH release MANY OH -

 ACIDS/BASES/pH pH- “power of the hydrogen ion”
-ion: charged atom or molecule
IDENTIFY what the pH scale measures-
how acidic / basic substance is
-substances INCREASE / DECREASE # H +
ACIDIC
0
NEUTRAL
7
BASIC
14

 pH

 BUFFERS
-solution which RESIST changes in pH when small quantities of an acid or alkali added to it.
-keep pH "in range": 6.5 7.5
-Organisms SURVIVE and FUNCTION despite metabolic activities that shift pH (acid/basic end of scale)
 DISCUSS/IDENTIFY the importance of buffers in biology.
-bring organism back to balance  HOMEOSTASIS

 DATA ANALYSIS
1- IDENTIFY the independent variable.
-pH/temp
2- IDENTIFY the dependent variable.
protease activity
3- IDENTIFY the range of pH values used in the experiment.
pH range 5-12
4- IDENTIFY the range of temperatures used in the experiment.
-temp range 30-90C

 DATA ANALYSIS
5- SUMMARIZE the results of the two graphs.
-highest activity pH10 / 60C
6- INFER/SUPPORT- if laundry detergent is basic and requires hot water to be most effective, would this protease be useful?
Yes, because the enzyme had the highest activity at a high pH (basic) and at a high temp.

EXIT
FILL-IN: level of understanding of today ’ s objective
  