8th Chem - Lab 1 - Term III

LABORATORY PRACTICE - BIOLOGY – 8TH GRADE MIXTURES AND SOLUTIONS Name: ______________________

Date: ___________

Section: _____

MATERIALS – Per Group (6 students) Lab Coat 1 Magnet 1 Roll Paper Towel 1 Plastic Funnel 6 Paper Filter (Coffee Filter) 200 grams Sand 200 grams Table Salt 200 ml Cooking Oil (Vegetable) 1 bottle Water (1.5 L) 1 Box of Corn Cereal (no sugar or chocolate, only Corn Flakes) 1 Dozen Plastic transparent cups (no white cups)

INSTRUCTIONS DO NOT proceed with any action unless indicated by your teacher.

When indicated, proceed cautiously and safely for yourself and your other classmates.

Observe all the materials, reactions and processes involved in the experiment.

Record information in the tables provided, you are allowed to use cameras to record the activity, only to document the activity for your lab report.

Put on lab coat, safety goggles, and gloves.

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PROCEDURE I: Making and Separating Solutions 1. Choose the ingredients for your first mixture from the following: sand, salt, water, iron filings and cooking oil.

2. Enter the name and physical description of the ingredients that you chose in the data sheet.

3. Measure and separate 2.0 grams of each solid and 15 mL of water if needed.

4. Mix the ingredients in the beaker and stir with the stirring rod.

5. Record the description of the mixture in the table.

6. Write out a procedure for separating the mixture in the data sheet.

7. Follow your procedure and separate the mixture.

8. Save all the parts of the mixture and show them to your teacher.

9. Repeat the procedure in steps 1-4 for your second mixture.

PROCEDURE II: Determining the Percentage of Parts of a Mixture 1. Place an empty cup on the electronic balance, press "tare" to remove the mass of the cup.

2. Fill a 100 mL beaker with the breakfast cereal. Transfer the cereal, a little at a time, to a mortar and grind it to a powder. Transfer the ground cereal to the cup.

3. When you are finished grinding all the cereal from the beaker and transferring it to the cup, find the mass.

4. Enter the results in the table.

5. Place the magnet into the ground cereal and stir it around several times to collect the reduced iron.

6. Remove the magnet and rub off the particles that stuck to it onto a piece of scrap paper.

7. Repeat this procedure several times to ensure you have collected as much iron as you can.

8. Remove any items that are clearly not magnetic.

9. Measure the mass of the cup and contents again and record the mass in the table.

10. Subtract the mass of the cup and contents after the iron was removed from the original mass of the cup and contents to find the mass of the iron that was removed.

11. Enter the value in the table.

12. Find the percentage of iron in the cereal by dividing the mass of the iron by the original mass of the cereal and then multiply by 100.

Mass of Iron x 100 = %Iron in Cereal Mass of Cereal

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PROCEDURE III (OPTIONAL): Investigate the effect of Salt over the Freezing Point of Water 1. Fill a 250 mL beaker 2/3 full of crushed ice. Add water to fill up the spaces between the ice. Stir well.

2. Measure and record the temperature.

3. Add 5 grams of salt (NaCl) to the ice water mixture and stir well to dissolve the salt.

4. Measure and record the temperature.

5. Predict what will happen when a second 5 grams of salt is added to the solution. Add the salt (total 10 grams).

6. Stir to dissolve and record the temperature.

7. Add another 5 grams (total 15). Stir and dissolve.

8. Measure and record the temperature again.

9. Keep adding salt, 5 grams at a time, dissolving and recording the temperature each time.

10. Make a data chart and graph Grams of Salt vs. Temperature.

QUESTIONNAIRE 1. How do the properties of a mixture differ from the properties of the components of the mixture?

2. In terms of physical properties, what is there about mixtures that makes it possible to separate out the components?

3. Describe in detail the steps you would take to find the percentage of salt in a sample of salt water.

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MIXTURES AND SOLUTIONS DATA SHEET

Mixture 1 INGREDIENTS

DESCRIPTION

Description of Mixture

Procedures to separate Mixture 1 1.

2.

3.

4.

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Mixture 2 INGREDIENTS

DESCRIPTION

Description of Mixture

Procedures to separate Mixture 2 1.

2.

3.

4.

Original Mass of Cereal (grams) Mass of Cereal after Iron is Removed (g) Mass of Iron (g) Percentage of Iron contained in Cereal (%)

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