17-1

**Ice Cream Lab** **//<---Unit Header - Next Assignment--->media type="custom" key="7093633"//** __** Instructions **__
 * // Make a new page on your wiki titled "17-1" //
 * // Answer the prelab questions first, make the ice cream, then answer the analysis questions //
 * // All questions must be answered to get the full grade //

__** Lab **__ Who knew chemistry could be so tasty! Today we will be investigating how additives affect solutions, specifically by how they affect freezing points, and some yummy results of energy changes.

__Pre-Lab reading__ Ice cream, a mixture of milk, sugar and vanilla, is really an aqueous mixture (which means dissolved in water) with many particles in each liter. When you add particles to water it makes it harder to freeze, so the temperature must be lower than pure water. Because of this, the freezing point of ice cream is lower than that of water. So to freeze ice cream, or to keep it frozen, you must keep its temperature significantly below 0 degrees Celsius. Adding salt to ice produces a melting ice and saltwater mixture with a depressed (lowered) freezing point in which the ice cream can be frozen.


 * __PRE-LAB QUESTIONS__**

1)Is the freezing point of ice cream lower or higher than the freezing point of water? 2)To freeze ice cream, what temperature must it be lower than? 3)What does adding salt to ice do? 4)Is this an endothermic reaction(requires energy so it gets colder) or exothermic reaction (Gives off energy so it gets hotter)? 5)Out of (ice, milk, salt, vanilla, sugar) Which of the 5 ingredients do you want IN the ice cream? 6)Which of the 5 ingredients should NOT be in the ice cream? 7)You have two baggies. One big, one small. Why do you need 2 baggies for this experiment?

PLEASE MEASURE AND POUR OVER THE SINK. CLEAN UP YOUR MESSES. In Small Bag In Large Bag Put closed small bag in big bag (Do not mix the contents) Shake the bag for nearly 5 minutes or till it feels firm over a sink
 * __Instructions__**
 * 1/2 cup milk
 * 1/4 teaspoon vanilla (Or other flavor)
 * 1 tablespoon sugar
 * 1/2 full of ice
 * 2 tablespoons salt
 * Put the small bag zipped up

__**Analysis**:__ 8)What state of matter was the milk when you began? 9)What state of matter was the milk when you were done? 10)If you did not add sugar, would the ice cream freeze faster or slower? Why? Explain, using your knowledge of chemistry. (read the beginning paragraph) 11)Why did the outside of the bag get wet? (assume that your bag did not spring a leak.) 12)Where did the water on the outside of your bag come from?