Activity 45 Follow-up Discuss in your groups why you think the blue substance that formed during the reaction between copper chloride and sodium carbonate is evidence of a new substance. — reactants were two clear liquid solutions — products were a blue solid and liquid

Reactants Products CuCl 2 + Na 2 CO 3 CuCO 3 + 2NaCl Copper chloride + sodium carbonate Copper carbonate + sodium chloride liquid + liquid solid + liquid The copper carbonate was removed with the filter paper while the sodium chloride remained in solution. The dissolved sodium chloride is much less toxic than the dissolved copper chloride, however, even sodium chloride can cause problems if the concentration becomes too high.

Discuss Analysis Questions

Activity 46: Investigating Solutions of Acids and Bases

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

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.

Procedure: Follow procedure on pgs. C-83 to C-85 Part A: in step 2 you must discuss a plan and WRITE it in your notebook. Please read step 2. Step 7: write the cup number you will place each liquid to be tested in on the left hand margin of your table.

Procedure cont.: Use the following information to determine whether the household liquids are an acid, a base, or neutral. Write it in your notebook. Water –Neutral Hydrochloric Acid (HCl) –Acid Potassium Hydroxide (KOH) –Base Test the other solutions and compare.

Table 1: Liquids Distilled water Hydrochloric acid Potassium hydroxide Vinegar Ammonia w/ water Baking soda w/ water Milk Rubbing alcohol Sprite w/ water Phenolphthalein Write cup numbers based on your plan

Part B: Discussion What do you think will happen to the pH of the acid or base if you dilute it with water? –As you add water, the pH gets closer to neutral.

Analysis Question #1 AcidicNeutralBasic Hydrochloric Acid Water Potassium Hydroxide SpriteRubbing AlcoholAmmonia Vinegar Milk Baking Soda in Water