SEPARATING A SOLUBLE AND AN INSOLUBLE SUBSTANCE

1
LESSON 15

• SEPARATING A SOLUBLE AND AN INSOLUBLE SUBSTANCE

2
OBJECTIVES

• DISCUSS EVAPORATION AS A SEPARATION TECHNIQUE.
• FILTER MIXTURES CONTAINING WATER.
• DESIGN AND CONDUCT AN INQUIRY TO CLEAN ROCK SALT.

3
GETTING STARTED

• COLLECT A TOTE TRAY OF MATERIALS.
• COLLECT THE CUP OF COPPER (II) SULFATE SOLUTION
  FROM LESSON 12.
• USE A MAGNIFYING LOUPE TO EXAMINE THE CONTENTS OF
  THE PLASTIC CONTAINER.
• RECORD YOUR OBSERVATIONS. BE PREPARED TO SHARE
  WITH THE CLASS.

4

• SHARE YOUR OBSERVATIONS.

5

• RECORD IN YOUR NOTEBOOK
• WHAT DO YOU THINK THIS BLUE SUBSTANCE IS?
• HOW DID IT GET THERE?
• WHERE DID THE WATER
• GO?

6
HOW WOULD YOU..

• INCREASE THE RATE OF EVAPORATION OF THE SOLVENT??
• BY HEATING, INCREASE THE SURFACE AREA, INCREASING
  THE AIR FLOW OVER THE SURFACE OF THE SOLUTION.
• CHANGE THE AMOUNT OF TIME IT WOULD TAKE TO OBTAIN
  CRYSTALS FROM THE COPPER (II) SULFATE SOLUTION??
• DISSOLVE THE SOLUTE IN THE LEAST POSSIBLE AMOUNT
  OF SOLVENT GREATLY REDUCES THE EVAPORATION TME.

7
WHAT WOULD HAPPEN IF

• You added 25 mL of water to the cup of crystals?
  RECORD THIS PREDICTION IN YOUR NOTEBOOK.
• TEST YOUR PREDICTIONS.

8
PROPERTIES OF A SOLUTION

• What happens after you add 25 mL of water to the
  blue crystals?
• What are the properties of the mixture?
• What do you think you have made?

9
INQUIRY 15.1 MATERIALS
10
SAFETY TIPS

• WEAR YOUR SAFETY GOGGLES AT ALL TIMES.
• DONT TASTE OR EAT ANY OF THE MATERIALS.

11
PROCEDURE

• FOLD THE FILTER PAPER AS SHOWN ON PG. 124 AND
  INSERT INTO THE FUNNEL.
• WET THE PAPER WITH A FEW DROPS OF WATER.

12

• RECORD YOUR PREDICTION ON TABLE 1 ON STUDENT
  SHEET 15.1 IN REGARDS TO WHAT YOU THINK WILL
  HAPPEN TO THE COPPER (II) SULFATE SOLUTION IF YOU
  POUR IT INTO THE FUNNEL?

13

• PLACE A TEST TUBE IN THE TEST TUBE RACK. PLACE
  THE FUNNEL WITH THE FILTER PAPER INTO THE TEST
  TUBE. (FIG. 15.2, PG. 125)
• TEST YOUR PREDICTION BY POURING THE SOLUTION INTO
  THE FUNNEL.
• MAKE SURE THE SOLUTION DOES NOT GO OVER THE EDGE.
• RECORD YOUR RESULT IN TABLE 1.

14

• DISPOSE OF THE FILTER PAPER. FOLD A NEW ONE AND
  PUT IT IN THE FILTER FUNNEL.
• ADD ONE LAB SCOOP OF ZINC OXIDE TO APPROXIMATELY
  10 ML OF WATER IN A 250-ML BEAKER.
• STIR THE MIXTURE WITH A TEASPOON.
• PREDICT AND RECORD WHAT WILL HAPPEN WHEN YOU
  FILTER THIS MIXTURE?
• REPEAT THE FILTRATION PROCESS WITH A CLEAN TEST
  TUBE. RECORD YOUR RESULT IN TABLE 1.

15
REFLECTIONS 15.1

• 1. WHAT EFFECT DID FILTRATION HAVE ON THE 2
  MIXTURES?
• 2. CAN YOU THINK OF ANOTHER PROPERTY (OTHER THAN
  CLEARNESS AND UNIFORMITY OF COLOR) OF SOLUTIONS?

16
CLEAN UP

• USE THE PLASTIC CONTAINERS AT THE FRONT OF THE
  ROOM TO DISPOSE OF THE COPPER (II) SULFATE
  SOLUTION AND THE ZINC OXIDE SOLUTION.
• PUT USED FILTER PAPER IN THE TRASH.
• RINSE AND DRY OUT THE TOTE TRAY AND UTENSILS.
• BE SURE THE FILTER PAPER AND CHEMICALS ARE
  REPLACED FOR THE NEXT CLASS.

17
INQUIRY 15.2

• CLEANING ROCK SALT

18
GETTING STARTED

• ROCK SALT IMPURE FORM OF SALT OBTAINED BY
  MINING SALT DEPOSITS.
• LOOK AT THE PICTURE ON PG. 126.
• EXAMINE A SAMPLE OF ROCK SALT.
• DESCRIBE THE ROCK SALT ON STUDENT SHEET 15.2.

19
DISCUSS AND RECORD

• A. WOULD YOU WANT TO EAT THIS SAMPLE?
• B. DO YOU THINK IT IS PURE?
• C. WHAT DO YOU THINK THE CONTAMINANTS COULD BE?

20
DESIGN A PROCEDURE..

• HOW COULD YOU USE THE APPARATUS USED IN 15.1 TO
  OBTAIN ONLY THE SOLUBLE COMPONENT OF THE ROCK
  SALT?
• RECORD YOUR ANSWERS TO THE QUESTIONS ON STUDENT
  SHEET 15.2.
• RECORD THE PROCEDURE DEVISED BY YOUR GROUP ON THE
  STUDENT SHEET.

21

• USING THE PROCEDURES DEVISED BY YOUR GROUP,
  PURIFY THE ROCK SALT IN YOUR TOTE TRAY.

22
REFLECTIONS 15.2

• 1. WHAT PROBLEMS DID YOU ENCOUNTER WITH YOUR
  PURIFYING PROCEDURE?
• 2. WHAT SUCCESSES DID YOU ENCOUNTER WITH YOUR
  PURIFYING PROCESS?
• NOTE WE WILL REVISIT THE SALT SOLUTIONS IN A
  LATER LESSON AFTER THE WATER HAS HAD A CHANCE TO
  EVAPORATE FROM THE SOLUTION. LABEL YOUR
  CONTAINER WITH YOUR HOUR AND GROUP NUMBER.