Introduction

Greatness has returned with another outstanding lab performed by yours truly. You should already know that this blog is on an experiment that my chemistry teacher, Ms. Janik, has assigned.

This time we’re making ice cream folks.

I was excited too because for some reason on the day of the lab, I was really hungry.

Let’s get some background information on what we were actually doing for the experiment.

Background Information

Certain substances affect the state of ice. When salt is sprinkled on ice, for example, it causes the ice to melt. This chemical reaction is actually a heat energy transfer. Water freezes at 0°C. A saturated saltwater solution freezes at -32°C.

What happens if you sprinkle salt on ice?

The salt causes the ice to melt.

Material List:

ü  ½ cup milk

ü  ½ cup whipping cream (heavy cream)

ü  ¼ cup sugar

ü  ¼  teaspoon vanilla or vanilla flavoring (vanillin)

ü  ¾ cup sodium chloride (NaCl) as table salt or rock salt

ü  2 cups ice

ü  1-quart Ziploc bag

ü  1-gallon Ziploc bag

ü  Thermometer

ü  Measuring cups and spoons

ü  Cups and spoons for eating your treat!

Procedure:

1.     Add ¼ cup sugar, ½ cup milk, ½ cup whipping cream, and ¼ teaspoon vanilla to the quart Ziploc bag. Seal the bag securely.

2.     Put 2 cups of ice into the gallon Ziploc bag.

3.     Use the thermometer to measure and record the temperature of the ice in the gallon bag.

4.     Add ½ to ¾ cup salt (sodium chloride) to the bag of ice.

5.     Place the sealed quart bag inside

      Data:

1.      What kind of ice cream are you making?

Vanilla

2.      Document the temperature of the ice in the gallon bag before adding the salt.

0°C

3.      Document the temperature of the ice/salt mixture (not the ice cream) in the gallon bag when the ice cream mixture begins to solidify.

-3°C

4.      What is the temperature difference before adding the salt and after mixing for 5 minutes?

-3

5.      What is the temperature difference before adding the salt and after mixing for 10 minutes?

-10

Conclusion Questions

1.     What kind of chemical reaction is the process of cream making, as done in our lab? Explain Why.

The process of making ice cream is a synthesis reaction because it uses two or more substances to form a new compound.

2.     Explain why salt water is harder to freeze than plain water.

The difference in freezing points is why. Water freezes at 0°C, however saltwater freezes at -32°C.

3.     Is the process of making ice cream a physical or chemical change? Explain your answer.

The process of making ice cream is technically a physical change because you are just changing a liquid into solid, or at least a semi- solid because no one wants their ice cream to be rock solid.

4.      Why is salt used with the ice instead of sugar?

Both salt and sugar would make ice melt at the same speed. Neither is faster than the other. You can use either one in this ice cream lab. However, sugar is far more expensive than salt, so you should probably stick to salt.