Lab 2. Sweet Tooth. Solubility and Colligative Properties of Solutions: , Soda, and Ice Cream

How do I make a stronger cup of coffee? How do I make ice cream?

Objectives (i) describe the molecular basis of the solution process (ii) relate solute amount to a colligative property of a solution (iii) determine the solubility of a gas with temperature and pressure

Introduction Your mid-morning ritual: a little for a pick-me-up. You will make candy, look at how sugar composition determnes candy texture, and see how boiling point is related to sugar composition to make different types of candy. Your afternoon pick-me-up: your favorite soda. You like the whoosh sound when you open the car, the sugar, caffeine, the tart taste, and the bubbles. Where do the bubbles come from? How do I keep my soda from going flat? You will look at what makes soda go flat. Your special dessert: ice cream. How do you make home-made ice cream? You can use the freezing point depression colligative property of solutions to lower the freezing point of ice to make ice cream.

Materials Part A: Make sugar glass Students: bring some table sugar (), corn , a cooking pot, a spoon, and cooking thermometer (measures to 350oF/180oC)) hot plate Al foil Vegetable oil

Caution: hot plates get hot.

Part B: THREE bottles or cans of carbonated water or soda Students: bring in 3 small bottles or cans of soda Balloon 500 ml or 1 l graduated cylinder

Part C: Make Candy Students: bring some table sugar (sucrose), , milk, a cooking pot or pan, spoon, and cooking thermometer (measures to 350oF/180oC)) hot plate Al foil Vegetable oil

Part D: Freezing Point Depression and Ice Cream We will supply: You (Students) need to bring: large ziplock baggie (gallon size) Ingredients to make ice cream, e.g., small ziplock baggie (quart size) half-half milk/cream mixture crushed ice sugar coarse rock salt vanilla flavoring, e.g., chocolate or strawberry syrup

English/Metric Conversions: 1 pint = 2 cups, 4 cups = 1 quart, 4 quarts = 1 gallon 1 cup = 8 ounces = 240 ml

Part A. Sugar solution composition behavior. Making Sugar Glass Prelab Spend 5 minutes doing the following activity. Assign a notetaker. Report to class. 1. You add sugar (sucrose) to water. The sugar ____. a. Draw structures of sucrose and water. b. Identify the chemical forces between sucrose and water.

22 c. Sucrose is a that contains two : and . Draw the structures of glucose and fructose. d. Look up solubility of sucrose in water at 25oC in g sucrose/100 ml of water. e. You dissolve this mass of sucrose in 100 ml of water. A ____ solution forms. f. Look up solubility of sucrose in water at 50oC in g sucrose in 100 ml of water. g. Does the solubility of sucrose in water change with temperature? h. You heat up your solution from 1e from 25oC to 50oC. Is the warm sugar solution still a saturated solution?

2. You want to make a 50% sugar (sucrose) by mass solution. a. Calculate the mass of sugar in g and mass of water in g to make 100 g of this solution. b. A solution consists of a solute and solvent. One definition of a solvent is the substance present in the greatest amount. Another definition of a solvent is the substance in which a solute dissolves to form a solution. What is the solvent in this solution? Which definition are you using? c. Molality units are moles of solute/kg of solvent. Calculate the molality of the 50% sugar solution. d. Molarity units are moles of solute/liter of solution. 100 g of 50% sugar solution is not equal to 100 ml of solution because ____. Calculate the Molarity of the 50% sugar solution. The density of a 50% sugar solution is 1.23 g/ml. e. The boiling point of water is 100oC. Will the boiling point of this sugar solution be higher, lower, or 100oC?

3. We humans love sweets, especially candy. The type of candy depends on the sugar concentration, which can be determined from boiling point. Table 1 shows the sugar concentrations, the boiling points of sugar solutions, and sugar syrup behavior for different candy types. You will make sugar glass in lab. For each blank, predict the syrup behavior and candy type. Syrup behavior choices: Soft ball, Firm ball, Soft crack, Hard crack Candy type choices: fudge, , taffy, sugar glass

Table 1. Sugar concentration, boiling point, and cold water test behavior. (adapted from https://www.craftybaking.com/)

% sugar Syrup b.p., oC Syrup behavior in cold water test Candy type by mass (oF) 60-80 102-113 Thread: forms spider web in air (215-235oF) 85 113-116 _____: forms in cold water but flattens in your hand (235-240) when removed from water 87 118-121 _____: will flatten when squeezed after removing from (245-250) water 92 121-130 Hard ball: retains shape after removing from water Marshmallows (250-265) 95 132-143 _____: Syrup dropped into ice water separates into (270-290) hard but pliable threads. They will bend slightly before breaking. 99 149-154 _____: Syrup dropped into ice water separates into brittle (300-310) hard, brittle threads that break when bent.

4. a. Read the Procedure for Part A. List the data you will collect for this experiment. What instrument will you use to collect each piece of data? b. Identify the result you want to determine from this experiment.

Procedure DO NOT use any of the equipment in your locker. Use the pot you brought from home. 1. Prepare a cold water test and greased Al foil. a. Add cold water to two containers. Keep the water cold. You will use the cold water for a cold water test. The cold water test was used by confectioners (before themometers) to determine the candy type. In this test, a sample of hot sugar syrup is cooled quickly by dropping it into cold water. The composition (%

23 sugar) of the syrup determines the behavior of the syrup; the behavior tells the candy maker the type of candy that can be made from the syrup. Use one cold water container for Step 4. Use the other cold water container for Steps 5(ii) and 6(ii) fast cooling of your sugar glass. b. Prepare a piece of 1 square foot Al foil. Coat the Al foil lightly with vegetable oil. You will use this Al foil to make sugar glass in Steps 5 and 6.

2. Calibrate your cooking thermometer by measuring the ____ of _____. Measure 100 ml of water and pour the water into your pot or pan. Heat your water to boiling. Thermometer reading = ___ oC at b.p. of water. If your cooking thermometer reads xoC greater than the standard temperature, should you add or subtract xoC to get the actual temperature?

3. Prepare a 50% by mass sugar solution. USE YOUR COOKING POT FOR THIS PART. a. Measure 100 g of sucrose (1/2 cup) and add it to ___ g of water to make a 50% by mass sugar solution. Calculate the mass of water and volume of water to make this solution. Add you calculated mass or volume of water to the 100 g of sucrose. Make sure all of the sugar is dissolved. The mass of this solution is ____ g. The volume of this solution is ____ ml. The density of this solution is ____ g/ml. Compare this density to the density value given in Prelab Question 2d. Identify the chemical forces between water molecules. Identify the chemical forces between sugar and sugar molecules. Identify the chemical forces between water and sugar molecules. Sugar is soluble in water because sucrose disrupts the ___ between water molecules and water is able to break the ____ between sucrose molecules. Fill in the blanks. b. Attach your cooking thermometer to a ring and ring stand. Insert your thermometer in your sugar solution. Make sure the thermometer tip is NOT touching the bottom or sides of your pot.

4. Test the behavior of sugar syrup at different compositions. Identify the forces between solute and solvent. a. Start heating your 50% sugar solution. When it starts to boil, measure the temperature. This temperature is called the ____ of this solution. Fill in the blank. What substance is removed from the solution? Which substance is more volatile, sugar or water? As you continue to heat this solution, what happens to the sugar concentration of the solution? As ___ is removed from the solution and the concentration ____, the boiling point of the solution _____. Fill in the blanks. When water boils, water molecules have sufficient energy to escape from the liquid. When an aqueous solution boils, such as this sugar solution, the boiling point INCREASES because it is ___ (easier or harder?) ___ for water molecules to escape. Fill in the blank. Explain the role of the solute to make the boiling point increase. b. When the temperature reaches 105 oC (remember your thermometer calibration), take a small amount of your sugar solution (syrup) in a spoon, hold it about 2 inches above the syrup, and drop back into pot. Did you see a thread (spider web) form? When the thread is cool, touch the solidified sugar. Does it feel hard or soft? What kind of candy (syrup, fudge, caramel, taffy, ) could you use this sugar for? Record your observations in Table 2. c. See Table 2. Continue heating the sugar solution. When the sugar solution reaches each temperature (remember your thermometer calibration), do the following: (i) take a small amount of your sugar solution (syrup) and drop it into the cold water cup. What happens? Choices: Soft ball, Firm ball, hard ball, Soft crack, Hard crack (ii) Remove the sugar lump from the bottom of the cold water. Does it feel soft, firm, or hard? (iii) Is the softness, firmness, or hardness of the sugar lump due mainly to solute-solute chemical forces, solute-solvent forces, or solvent-solvent forces? The solvent is water and the solute is sugar. (iv) What kind of candy (syrup, fudge, caramel, taffy, hard candy) could you use this sugar lump for?

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Table 2. Sugar syrup boiling point and cold water test data. Sugar syrup Cold water test observation Soft, firm, or Solute-solute, Candy type temperature, hard? solute-solvent, or oC solvent-solvent? 105 thread 115 120 130 marshmallow 140 150 d. Maintain your sugar syrup at 150oC and go to Step 5.

5. Make sugar glass. Sugar glass used to be used in the movies to substitute for regular window glass. When a person was thrown through sugar glass, the broken glass would not cut the person. a. Is your hot sugar solution a saturated or unsaturated solution? You will cool your very hot 150oC sugar syrup solution two ways: (i) slow cooling Using HALF of your very hot 150oC sugar syrup solution, CAREFULLY pour the solution onto the greased Al foil. Spread the syrup evenly evenly and gently on the Al foil. Let the syrup cool. When cool, remove (peel off) the Al foil. (ii) fast cooling (quenching) Using the other HALF of your very hot 150oC sugar syrup solution, CAREFULLY pour the solution into cold water. Remove the solid from the cold water.

As the saturated solution cools, the liquid starts to solidify. This means the ____ molecules are bonding together through ____ forces and forming crystals. Crystals form because the water molecules move _____ as the solution temperature decreases and can not prevent ____ molecules from joining together. When the syrup has cooled, you should have sugar glass. Fill in the blanks. b. Describe your sugar glass. (i) slow cooling Is the glass transparent? Can you see through it? Or did you see sugar crystals form in the glass? Carefully hold your sugar glass. Is sugar glass hard or soft? Is sugar glass brittle? Drop something on the glass to break it. Carefully pick up a broken piece. Are the edges sharp like regular window glass? Could you use the sugar glass for soft candy or hard candy? Taste your sugar glass (analyze your data). Could you use the sugar glass for soft candy or hard candy?

(ii) fast cooling (quenching) Is the glass transparent? Can you see through it? Or did you see sugar crystals form in the glass? Carefully hold your sugar glass. Is sugar glass hard or soft? Is sugar glass brittle? Drop something on the glass to break it. Carefully pick up a broken piece. Are the edges sharp like regular window glass? Taste your sugar glass (analyze your data). Could you use the sugar glass for soft candy or hard candy?

Glasses are amorphous solids (random arrangement of molecules) and are transparent because individual ____ molecules are too ___ to scatter light. Fill in the blanks. Crystalline solids are opaque because crystals (ordered arrangement of molecules) consist of __ (many or few?) _ molecules and are ___ than individual molecules and will scatter light. Fill in the blanks.

6. Make clear sugar glass with sugar and corn syrup.

25 Candy makers do not make their from sucrose only because it is difficult to control or prevent crystallization of the sucrose. Other substances are added to that interfere or limit sucrose crystallization. Add 100 g of sugar to 100 ml of water. Add 25 g corn syrup. See the corn syrup label. Glucose is the sugar in corn syrup. Calculate the % glucose in corn syrup, Molarity of glucose in corn syrup, and molality of glucose in corn syrup. Heat the sugar-corn syrup solution to 150oC. Repeat Step 4. Analyze your data: Describe any difference in the sugar glass between slow cooling and fast cooling.

In Step 4, you made sugar glass from sucrose only. Your sugar glass may have been opaque due to the formation of sucrose crystals. Which molecule is larger, sucrose or glucose? How does glucose interfere or limit sucrose from crystallizing?

Waste Disposal: Dissolve the sugar glass in water and wash the solution down drain. Clean any sugar or syrup from your lab area; otherwise, your lab area will be visited by ants.

Part B. Solubility of a gas in a liquid. Carbonated beverages. Prelab Spend 5 minutes doing the following activity. Assign a notetaker. Report to class. 1. Soda and soda water are carbonated. How is soda or water carbonated? Consider the following reactions:

H2CO3 (aq) ----> H2O (l) + CO2 (g) (1)

+ - H2CO3 (aq) <===> H (aq) + HCO3 (aq) (2)

CO2 (g) <====> CO2 (aq) (3)

You brought two bottles or cans of soda to lab. One bottle/can will be cold. For the other bottle/can, do the following and record your observations: (i) shake the bottle for 30 seconds. (ii) Put the bottle in a hot water bath. a. What is the solvent in soda? b. How can you determine the pressure of gas in the each unopened bottle? c. Look up the solubility of CO2 in water at room temperature. Cite the reference where you found this information. d. Your answer to c tells you CO2 is ____ soluble in water. Choices: not, slightly, very See Reaction (3). Would you expect to see a lot or a little CO2 (aq) produced in this reaction?

2. a. Read the Procedure for Part B. List the data you will collect for this experiment. b. Identify the result that you will calculate from a formula or equation in this experiment.

Procedure 1. You will experimentally determine the pressure of gas in soda three (3) ways: i. put a balloon or rubber glove over the soda and secure the balloon or rubber glove tightly over the lip. A twist tie should work well. Carefully open the soda. The escaping gas should inflate the balloon or rubber glove. When the balloon or rubber glove has inflated as much as you think it will inflate, carefully squeeze the balloon or rubber glove. What happens? Carefully take the balloon or rubber glove off the soda and tie it. Try not to let any gas escape. Measure the volume of the balloon or rubber glove. Calculate the moles and mass of gas in the balloon or glove. Based on this information, calculate the pressure of gas in the soda before you opened it. Record your data in Table 3. ii. If you have a can of soda, open the soda and quickly pour the contents into a 1 liter graduated cylinder. Measure the volume of liquid and the volume of foam. What is the solvent in this foam? What is the solute in this foam? What does the volume of foam tell you? Using the volume of

26 foam, calculate the moles and mass of gas. Calculate the pressure of gas in the soda. Record your data in Table 3. iii. Calculate the pressure of CO2 in your soda based on Chang, “General Chemistry: The Essential Concepts,” 7th ed, Problem 13.111. “A student carried out the following procedure to measure the pressure of CO2 in a bottle. First, she weighed the bottle (_____ g). Next, she carefully

removed the cap to let the CO2 gas escape. She then reweighed the bottle with the cap (____ g).

Finally, she measured the volume of the soft drink (_____ ml). Given that Henry's law constant for o -2 CO2 in water at 25 C is 3.4x10 mol/L atm, calculate the pressure of CO2 in the original bottle. Why is this pressure only an estimate of the true value?” Measure the appropriate quantities for your soda. Record your data in Table 3.

Table 3. Determination of Gas Pressure in a Soda. Method i Method i Method ii Method ii Method iii Method iii

Soda Soda Soda brand/can or brand/can or brand/can or bottle bottle bottle Volume of Volume of Mass of soda, balloon, ml liquid, ml g

Volume of Mass of soda foam, ml after CO2 escaped, g

Moles of gas Moles of gas Mass of CO2 in balloon in soda, g

Moles of gas Moles of gas in Moles of CO2 in soda soda before before opening opening Volume of Volume of gas Volume of gas in soda in soda (space soda, ml (space between liquid between and top of liquid and top can/bottle), ml of can/bottle), ml Pressure in Pressure in Pressure in soda, atm soda, atm soda, atm

2. Analyze your results. Which method gives the most accurate pressure? a. Compare the pressures you measured in Step 1. Are these pressures the same? Calculate an average pressure and % difference. Which method do you think has the highest experimental error? b. Draw a conclusion from this experiment.

3. There are at least two ways to keep soda from going flat. Draw a picture that describes each way to keep soda from going flat based on your results.

Waste Disposal: carbonated beverages – in sink.

Part C. Make different types of candy. Prelab Spend 5 minutes doing the following activity. Assign a notetaker. Report to class.

27 1. Milk Duds or Jolly Ranchers? a. Which candy, Milk Duds or Jolly Ranchers, do you think has a higher % sugar? b. Predict the relationship (direct, inverse, or no relationship) between the % sugar and candy hardness. c. Are Jolly Ranchers hard due mainly to solute-solute chemical forces, solute-solvent forces, or solvent- solvent forces? The solvent is water and the solute is sugar. d. Are Milk Duds soft due mainly to solute-solute chemical forces, solute-solvent forces, or solvent-solvent forces? The solvent is water and the solute is sugar.

2. Boiling point elevation. When a solute is added to a solvent to form a solution, the boiling point of the solution is greater than the boiling point of the pure solvent. a. Water has a boiling point of 100oC. Look up the boiling point of sucrose in oC. b. Table 1 from Part A shows a 60-80% sugar solution has a boiling point of 102-113oC. A solution consists of a solute and solvent. One definition of a solvent is the substance present in the greatest amount. Another definition of a solvent is the substance in which a solute dissolves to form a solution. What is the solvent in an 80% sugar solution? Which definition are you using? c. If the solvent was sucrose, the boiling point of an 80% sugar solution would have to be greater than ____ oC. d. When a solvent evaporates, the solvent molecules at the surface escape to the gas phase. Does a solute make it easier or harder for the solvent to escape to the gas phase? e. Does your answer to the previous question cause the b.p. to increase or decrease?

3. Calculate the boiling point of each sugar solution. Table 4. Sugar concentration, boiling point, calculated boiling point using boiling point elevation.

o o % sugar Syrup b.p., C molality, ΔTb, C solution % difference Candy type by mass (oF) moles/kg b.p., oC in b.p. 60-80 102-113 4.4 2.2 102 0 Syrups (215-235oF) 85 113-116 (235-240) 87 118-121 (245-250) 92 121-130 Marshmallows (250-265) 95 132-143 (270-290) 99 149-154 Brittle (300-310)

See Table 4. For each solution, a. assume the mass of sugar equals the % sugar. E.g., 60% sugar = 60 g sugar. Use sucrose for your sugar. Calculate the mass of water to make 100 g of solution. b. Convert % sugar to molality. c. Boiling point elevation is a colligative property of a solution: ΔTb = i Kb m where ΔTb = boiling point elevation = b.p. of solution – b.p. of pure solvent i = number of solute particles in solution o Kb = boiling point elevation constant for the solvent. Kb for water = 0.512 C/m m = molality Calculate the boiling point elevation. The syrup boiling point is greater than the boiling point of the solvent means the solute makes it harder for the water molecules to escape to the gas phase. What does the solute do to the solvent to make it harder for the solvent to escape to the gas phase? d. Calculate the boiling point of the solution. e. Compare your calculated boiling point to the syrup b.p. Calculate the % difference. f. Boiling point elevation, and all colligative properties, assume the solution is ideal (mean strength of interactions are the same between all substances in the solution), solute is non-volatile, solvent is volatile.

28 At what sugar composition did the syrup boiling point deviate from your calculated boiling point? Give a reason for the difference in your calculated boiling point and experimental boiling point.

4. a. Read the Procedure for Part C. List the data you will collect for this experiment. What instrument will you use to collect each piece of data? b. Identify the result you want to determine from this experiment.

Procedure DO NOT use any of the equipment in your locker. Use the pot or pan you brought from home. 1. Calibrate your cooking thermometer by measuring the ____ of _____. Measure 100 ml of water and pour the water into your pot or pan. Heat your water to boiling. Thermometer reading = ___ oC at b.p. of water. If your cooking thermometer reads xoC greater than the standard temperature, should you add or subtract xoC to get the actual temperature?

2. Caramelize sugar. a. Measure 100 g of sugar and 25 g of corn syrup in your pot or pan. Add just enough water to dissolve the sugar. This is a ___ solution. b. Heat the sugar/water mixture until the sugar starts to turn brown. Make it light brown or dark brown but don’t burn the sugar. c. Carefully smell the caramelized sugar by wafting the odor toward your nose. What does it smell like? Carefully taste the caramelized sugar. Does it taste as sweet as sucrose (table sugar)? If not, explain why the changed. d. Add 100 ml of water to the browned sugar. Dissolve the sugar. Add 10 ml of milk to the sugar solution. The protein in the milk reacts with the sugar to produce additional brown and aroma compounds.

3. Make different types of candy. a. Prepare several pieces of 1 square foot Al foil. Coat the Al foil lightly with vegetable oil. You will use this Al foil to let your candy cool. Start heating your sugar-milk solution.

If you heated pure water to its boiling point and continued heating, the temperature would ____. When you heat your sugar-milk solution to its boiling point, you should see the temperature of your sugar- milk solution ____ because _____. Which component of the solution is volatile? Water is the solvent because _____. In the next step, you will make candy. Note: If this happens, “OOPs! I heated the sugar solution too hot!” You can lower the temperature by removing the solution from the hot plate OR by __ (this way is faster) __. b. See Table 5. When the sugar solution reaches each temperature (remember your thermometer calibration), do the following: (i) take a spoonful of your sugar solution (syrup) and pour it onto the greased Al foil. Let it cool. (ii) Record your observations: Is the candy soft, firm, or hard? Is the candy translucent or opaque? What color is your candy? What type of candy (syrup, fudge, caramel, taffy, hard candy) did you make? Taste your candy (analyze your data). Does it taste like the candy type you answered in the previous question?

Table 5. Sugar syrup boiling point and candy type. Sugar syrup soft, firm, or hard? translucent or Candy color? Candy type temperature, oC opaque? 115 120

29 130 140 150 c. As the sugar syrup temperature increases, did the candy get softer or harder? To make soft candy, you want the main interaction in the candy to be: i. solute-solute chemical forces ii. solute-solvent forces iii. solvent-solvent forces Which sugar solution boiling point made caramel?

4. Make better caramel. a. Identify the parts of Steps 2 and 3 you want to modify to make a more delicious batch of caramel. Describe each modification you made. b. Heat your sugar solution to the desired temperature. Pour the ____ oC sugar solution onto a piece of greased Al foil. Let it cool. Remove the Al foil (peel it off the caramel). Taste your candy (analyze your data). Does it taste like caramel?

Waste Disposal: Dissolve your candy in water and wash the solution down drain. Clean any sugar or syrup from your lab area; otherwise, your lab area will be visited by ants.

Part D. Freezing point depression. Make ice cream. Prelab Spend 5 minutes doing the following activity. Assign a notetaker. Report to class. Ice cream is made by crystallizing a milk/cream/sugar/flavor mixture. BEFORE you make ice cream, do the following: (i) What is the solvent in ice cream? (ii) At what temperature will this milk mixture crystallize to make ice cream? Estimate the temperature you think this mixture will crystallize. Then, calculate the molal concentration of solute(s) in milk. What is the solute in milk that lowers its freezing point? Give reasons. (iii) Then, calculate the amount of rock salt and ice required to achieve this temperature. Your group can use a MAXIMUM of 50 g of rock salt and 2 cups of ice. Compare your calculation of the mass of NaCl to achieve this temperature another group. Did you get the same mass of NaCl and temperature?

Ice cream is made by crystallizing a milk/cream/sugar/flavor mixture. In ice cream, milk is the “solvent”; however, milk itself is a mixture that consists mostly of water.

Procedure 1. Combine your ice cream ingredients. a. Into the small ziplock baggie, place the milk, sugar, vanilla, and flavoring of your choice. Carefully seal the baggie completely to ensure that all the ingredients are safely locked inside (unless you enjoy salty ice cream!). b. Mix the ingredients into a homogeneous mixture together by kneading gently.

2. Prepare your ice bath. Fill the larger ziplock baggie with the mass of ice and rock salt that you calculated. (You want the bag to be about 1/2 full of ice and rock salt.) Mix the ice/salt into a homogeneous mixture by kneading gently. Measure the temperature of your rock salt/ice mixture. Is the temperature equal to the temperature you calculated before you started the lab?

3. Make your ice cream. a. Carefully place the small baggie with your sealed milk mixture into the large baggie with ice/salt and seal the large baggie. b. Shake and knead on a table or other hard surface for about 10-15 minutes or until the milk mixture hardens into ice cream.

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(Or use two large ziplock baggies with the small milk mixture in between – a milk mixture sandwich!)

4. Analyze your results. When your ice cream is done, a. Report the temperature of the rock salt/ice mixture. Is the temperature equal to the temperature you calculated before you started the lab? b. Carefully remove the small ziplock baggie from the larger baggie and gently rinse the ziplock seal on the small ziplock baggie with cold ice water. This rinses away the excess salt from your ice cream baggie. c. Test taste your ice cream. Describe the texture of the ice cream you made. Give your ice cream a letter grade. Describe the criteria you used for this grade. If you don’t think any contamination has occurred, offer some to your lab technician. b. Discuss the effect of temperature of your salt-ice mixture on your ice cream making process. Include numbers. d. Draw a conclusion from this experiment.

Waste Disposal: ice/salt mixture - in sink. Rinse out the large baggie with water and return in to your instructor for reuse. Dispose of your small baggie in the appropriate receptacle after you finish eating your ice cream.

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