Chemistry - Unit 4 Demo Notes

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Chemistry - Unit 4 Demo Notes

Part I – Pure Substances vs. Mixtures

1. What are some physical properties of substances?

2. What do you observe when you add sugar to water?

3. What do you observe when you add sugar to ethanol?

4. Draw particles diagrams for each of these observations:

sugar in water sugar in ethanol

5. What about water and ethanol?

6. What happens when you add sugar to the water and ethanol mixture?

7. Draw Particle Diagrams of each situation:

water and ethanol water, ethanol and sugar

8. What do you observe when you mix sand and salt?

9. How could you separate the mixture between sand and salt? (Hint: what do you know about water and sand? What about water and salt?)

10. A mixture is comprised of ______pure substances.

11. What do these activities tell you about the properties of mixtures?

12. Can you separate the mixture of water and ethanol? How?

13. If ethanol has a boiling point of 78.4oC what would the boiling point of water and ethanol appear to be?

14. Sketch a heating curve for the mixture water and ethanol.

15. Look up methods of mixture separation in your textbook and make a list complete with a description of each technique. You must discuss a minimum of three techniques.

Part II - Compounds

1. What do observe about the four samples?

Iron filings:

Sulfur:

Iron and Sulfur Sample #1:

Iron and Sulfur Sample #2:

2. What happens when your instructor passes a magnet through each of the iron and sulfur samples?

3. Propose an explanation for the results of each magnet pass.

4. Sketch particle diagrams of each of the iron and sulfur mixtures.

Fe and S sample #1 Fe and S sample #2

Electrolysis of Water

5. At what electrode is gas accumulating at faster?

6. What do you notice about the ratios of volume between the electrodes?

7. What do you think is happening to the liquid water?

8. How is the liquid splitting? Will it continue to split if the power was turned off?

9. What do you observe during the flaming splint test with Hydrogen?

10. What do you observe during the glowing splint test with Oxygen?

11. What can you say about the quantity of energy transferred during these reactions?

Notes for Video

Summary

Some pure substances can be ______into simpler substances. Those that cannot be broken down are said to be ______, those that can be broken down to elemental substances are ______. Not all the particles that form pure substances are simple, some contain smaller particles that combine, or are compounded, in ______and are not merely simple mixtures of these smaller particles.

Modeling Chemistry 1 U4 demo notes v.pp