Lara Khorma

Problem:

What are some signs that a chemical reaction has taken place?

 

Materials:

• 4 - 100mL Beakers

• Birthday candles

• Sugar

• Tongs

• Clay

• Matches

• Sodium carbonate

• Graduated cylinder, 10mL

• Aluminum foil 10 cm square

• Dilute hydrochloric acid

• Copper sulfate solution

• Sodium carbonate solution

 

Procedure:

Create a table like the one in the data section in MS Word.

Part 1: 

1. Put a pea-sized pile of sodium carbonate into a 100mL beaker. Record in the data table the appearance of the sodium carbonate.

2. Observe a dropper containing hydrochloric acid. Record the appearance of the acid.

3. Make a prediction about how you think the acid and the sodium carbonate will react.

4. Add about 10 drops of hydrochloric acid to the sodium carbonate. Swirl to mix the contents of the beaker. Record your observations.

Part 2:

1. Fold up the sides of the aluminum oil square to make a small tray.

2. Use a spatula to place a pea-sized pile of sugar into the tray.

3. Carefully describe the appearance of the sugar in your data table.

4. Predict what you think will happen if you heat the sugar. Record your prediction.

5. Secure a small candle on your desktop in a lump of clay. Carefully light the candle with a match only after being instructed to do so by your teacher.

6. Use tongs to hold the aluminum tray. Heat the sugar slowly by moving the tray gently back and forth over the flame. Make observations while the sugar is heating.

7. When you think there is no longer a chemical reaction occurring, blow out the candle.

8. Allow the tray to cool for a few seconds and set it down. Record your observations of the material left in the tray.

Part 3:

1. Put about 2 mL of copper sulfate solution in one beaker using a pipette. Caution: Copper sulfate is poisonous and can stain your skin and clothes. Do not touch it or get in in your mouth. Using a 10mL graduated cylinder, measure 2mL of sodium carbonate solution in another beaker. Record the appearance of both liquids.

2. Write a prediction of what you think will happen when the two solutions are mixed.

3. Combine the two solutions and record your observations.

4. Wash your hands.

Data:

Place a screen shot of the table from MS Word in this location.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analysis:

Which of your predictions were accurate?

 

The predictions that were accurate were that the temperature would have gotten hotter once we added the copper sulfate. 

 

What was the biggest surprise?

 

The biggest surprise for us was seeing the temperature change so rapidly when we added different substances together. 

 

How did you know when the reaction in Part 1 was over?

 

We knew that the reaction in Part 1 was over because the temperature sustained the same degree and didn't change. 

 

What was the evidence of a chemical reaction in Part 1?

 

The evidence of a chemical reaction in Part 1 was the temperature dropping rapidly. 

 

What was the evidence of a chemical reaction in Part 2?

 

The evidence of a cehmical reaction in Part 2 was the temperature rising rapidly. 

 

Was the reaction in Part 1 endothermic or exothermic? Explain.

 

The reaction in Part 1 was endothermic because it was taking in the energy because the temperature dropped. 

 

Was the product of the reaction in Part 2 a solid, a liquid, or a gas?

 

The product of the reaction in Part 2 was a liquid. 

 

Conclusion:

(What did you learn from the activity? What are additional questions you have?)

 

What I learned from this activity is that when you add different substances with each other, they react and sometimes it's an endothermic reaction and sometimes it's an exothermic reaction. 

 

Additional questions: If we added more substances to the water, how would the reaction differ to how it was before?