Bell RingerBell Ringer

How does surface area affect How does surface area affect a chemical reaction?a chemical reaction?

Today’s Goal Today’s Goal

I can apply my knowledge of I can apply my knowledge of chemical reaction to the real world chemical reaction to the real world experience of making fudge. experience of making fudge.

I can identify endothermic and I can identify endothermic and exothermic reactions in real world exothermic reactions in real world situations.situations.

BeginBegin

Reactants Reactants • 3 cups sugar3 cups sugar• 1 ½ sticks of country crock butter1 ½ sticks of country crock butter• 2/3 cup of cream2/3 cup of cream• 1 (7 oz.) jar of marshmallow crème1 (7 oz.) jar of marshmallow crème• 1 (12 oz. package) of __________ chips. 1 (12 oz. package) of __________ chips. • Energy Energy

Recall that activation energy is Recall that activation energy is minimum amount of energy needed minimum amount of energy needed to start a reaction. to start a reaction.

The energy for today’s experiment The energy for today’s experiment will come from the hot plate. will come from the hot plate.

1. Explain how the energy gets from 1. Explain how the energy gets from the electrical outlet to the pan to the electrical outlet to the pan to heat the reactants.heat the reactants.

NextNext

In a panIn a pan Mix the first 3 ingredients (reactants) Mix the first 3 ingredients (reactants)

until they dissolve into one until they dissolve into one (compound) (compound)

This will happen as the heat goes This will happen as the heat goes into the pan (endothermic) into the pan (endothermic)

Look Look

Once they mix together to form a Once they mix together to form a compound compound OBSERVEOBSERVE the color of the the color of the compound.compound.

Record a description of your Record a description of your observation.observation.

At this point we observe for the At this point we observe for the mixture to begin to boil. mixture to begin to boil. The mixture The mixture must absorb enough energy to come must absorb enough energy to come to a rolling boil. (It cannot be stirred to a rolling boil. (It cannot be stirred down) OBSERVE Record observation. down) OBSERVE Record observation.

Now we begin to time. Time for 6 Now we begin to time. Time for 6 min. Then we will look at the color of min. Then we will look at the color of the compound. the compound.

Next Next

Time’s UPTime’s UP We remove the compound from the We remove the compound from the

energy.energy. Add the (inhibitor) chips, and Add the (inhibitor) chips, and

marshmallow crème. marshmallow crème. Mix thoroughly and immediately pour Mix thoroughly and immediately pour

in the pan. in the pan.

This is where the exothermic part of This is where the exothermic part of the reaction is taking place. the reaction is taking place.

Feel the heat being released. Feel the heat being released. Let the majority of the heat be Let the majority of the heat be

released. When the fudge is cool we released. When the fudge is cool we can eat it. can eat it.

While you are waiting! While you are waiting!

AssignmentAssignment

Write up this experiment. Write up this experiment. AnalysisAnalysis

• Explain in detail how making fudge is Explain in detail how making fudge is indeed a chemical reaction.indeed a chemical reaction.

• Use the vocabulary words. (page 514) Use the vocabulary words. (page 514) or your homework (the vocabulary or your homework (the vocabulary model) model)

• The analysis must use science The analysis must use science vocabulary correctly. vocabulary correctly.

• Terms to include: endothermic, Terms to include: endothermic, exothermic, reaction rate factors, exothermic, reaction rate factors, reactants, products, evidence of a reactants, products, evidence of a chemical changechemical change

• Be specific! Begin now while you wait to Be specific! Begin now while you wait to eat your experiment. eat your experiment.

• Analysis is due tomorrow. You may use Analysis is due tomorrow. You may use your notes, book, etc…your notes, book, etc…