Activity 43 Follow-up

• Flocculate- To add chemicals into water to mix with and pull together the contaminants into large clumps

• Sediment- The clumps formed by flocculation that sink to the bottom of the water

• Sedimentation- The process of letting the clumps formed by flocculation sink to the bottom of the water

Cleaning the Water at a Water-Treatment Plant

Where does our water come from?

The Water Authority delivers water to the 23 retail water agencies that in turn deliver water to their retail customers.

Existing Water Resources Within SDCWA

Activity 43 Analysis

1. What do you know about the source of your community’s drinking water?

– Comes from Northern California via the California Aqueduct and the Colorado River Aqueduct

2. Do you think there are other communities that might contribute contaminants to your water source or get their water from the same source?

– Most of our water supply is surface water which is supplied from many rivers and streams

– See earlier map

3. Look at the map below, and find the Great Lakes. Why do you think the United States and Canada cooperate to keep the Great Lakes clean?

– The Great Lakes are bordered by both the United States and Canada.

– Both use water from the lakes – Both have communities and industries located

on the lakes– For these reasons, both want to be able to get

clean water from the lakes and work together to be sure that neither is polluting them

4. The reading describes two chemicals that are used to remove contaminants from drinking water. What are these chemicals, and what is the purpose of each one?

– Aluminum sulfate or other chemicals are used to coagulate and remove dirt and other contaminants

– Chlorine is used to kill biological contaminants

5. Which water source would you expect to be more likely to become contaminated by pesticides---surface water or groundwater? Explain why you think that.

– Surface water is more open to the environment– People can dump things into it and cause

contamination

Title: Investigating Solutions of Acids and Bases

Activity 46

What do you know about acids and bases?

• Acidic or basic water outside of a specific pH range violates federal standards for drinking water.

• Higher pH = more basic

• Lower pH = more acidic

• Neutral pH = 7

• Federal water-quality standards require testing for pH, because water with a high or low pH can corrode pipes and release harmful metals from the pipes into drinking water.

Read C-82

Problem: How can solutions be tested to identify them as acidic, basic, or neutral?

Initial Thoughts/Hypothesis:

In this activity you will…

• Work with several acid-base indicators:– Universal Indicator– Phenolphthalein– pH paper

• An indicator is a substance used to detect the presence of specific kinds of chemicals.

Background:Indicator Acid Base Neutral

Phenolphthalein Colorless Bright Pink Colorless

Universal Indicator

Red or Pink Blue Green

pH Paper Red or Orange-Red

Blue or Purple Yellow-Green

Procedure:

Follow procedure on pgs. C-83 to C-85

A data table will be provided for you. Discuss procedure step #2 with your group. Don’t write your plan in your notebook.

DO NOT GLUE YOUR TABLES IN YET!

Data/Observation:

Liquid Indicator

Phenolphthalein Universal Indicator

pH paper

Water from the sink

Hydrochloric Acid

Potassium Hydroxide

Rubbing Alcohol

Milk

Lemon Juice

Household Ammonia

Baking Soda in Water

Sprite

White Vinegar

Table 1: Indicator Test

You have 3 substances to test with 3 different indicators. How will you set up your tray?

Phen Phen PhenU.I. U.I. U.I.pH pH pH

Hydrochloric Acid (HCl)

Potassium Hydroxide (KOH)

Water from the Sink

Phenolphthalein Universal Indicator pH Paper

HCl KOH H2O HCl KOH H2O HCl KOH H2O

Demo:• Water

• Hydrochloric Acid (HCl)

• Potassium Hydroxide (KOH)

• Lemon juice

• Test the other solutions and compare.

Neutral

Acidic

Basic

Acidic

Part B

• What do you think will happen to the pH of the acid or base if you dilute it with water?– In part B is a serial dilution of HCl and KOH– Copy the results form the teacher

Table 2: Serial Dilution of 1% HCl Solution

Table 3: Serial Dilution of 1% KOH Solution