Flame Test

       I.            Objectives: The objectives are to use the flame test to determine the identity of the cation in an unknown solution based on its characteristic color flame.

    II.            Materials & Procedures:

A.    Materials: Bunsen burner, 7 small test tubes, test tube rack, 7 small cotton swabs, NaCl, CaCl₂, LiCl₂, KCl, BaCl₂, SrCl₂, CuCl₂

B.     Procedures:

1.Draw the data table including compound cation and color.

2.Label the test tubes and add 1ml of chemicals to the test tubes.

3.Dip one end of the swab in the chemical and hold it in the flame. Record the color. Set swab aside.

4.Repeat step 3 for each chemical using a different swab for each one.

C.     Safety:

 III.            Analysis:

A.    Data Table

Compound Formula	Cation	Color
NaCl
CaCl2
LiCl2
KCl
BaCl2
SrCl2
CuCl2

 

B.     Questions:

1.Each salt solution produces a unique color. Would you expect this based on the modern view of the atom? Explain.

2.Some commercially available fireplace logs burn with a red and/or green flame. On the basis of your data, what elements could be responsible for these colored flames?

3.Aerial fireworks contain gunpowder and chemicals that produce colors. What element would you include to produce crimson red? Yellow?

 IV.            Conclusion:

The Fat Content of Snack Food

       I.            Objective: In this experiment you will extract the fat from a snack food, calculate the amount of fat, and compare it to the amount of fat on the label.

    II.            Materials and Procedures:

A.    Materials:

-100 ml Beaker            -Balance          -Paper Towels             -Forceps          -Glass Funnel

-Snack Food                -Zip Lock Bag             -Stirring Rod               -Evaporating Dish

-Hexane           -Iron Ring       -Fume Hood                -Graduated Cylinder               -Goggles

-Filter Paper                -Ring Stand

B.     Procedures:

1.Place about 2g of a snack food in a zip lock bag and close the bag. Crush the food into extremely small pieces by smashing them with your hands.

2.Place an empty 100ml beaker on the balance pan and hit the tare button. Add the snack food to the beaker and record the mass in Table 1.

3.Measure approximately 15ml of hexane into a graduated cylinder. Add the hexane to the snack food in the beaker and stir for about 10 minutes. Use the stirring rod to ensure that all surfaces of then crumbs are wet with hexane. Leave the beaker in the fume hood.

4.Determine and record the mass of a piece of filter paper and evaporating dish.

5.Set up a filtration apparatus using the weighed filter paper, and evaporating dish and a funnel.

6.Gently swirl the mixture in the beaker and pour it into the filter paper. Add 5ml hexane to the beaker and swirl again to rinse the beaker. Pour this into the filter paper. Repeat the hexane rinsing a second time in order to get all of the mixture out of the beaker.

7.After all the liquid has passed through the filter paper, use forceps to carefully transfer the filter paper and its solid contents onto a layer of paper towels. Allow the paper to dry in the hood until all the hexane has evaporated. (This should take 20-30 minutes so we will wait over night.) Put name on towels.

8.Put name on the evaporating dish and place it in the fume hood until all of the hexane evaporates. This may take several days.

9.Determine and record the mass of the filter paper and its contents and the evaporating dish and its contents.

C.    Safety:

Do not eat or drink the lab materials. Do not set the beaker precariously on window sill or fume hood. Do not crush fingers instead of chips.

 III.            Analysis:

A.    Data- Type of snack food: Light Ruffles

Table 1: Mass Data

Object	Mass (g)
Mass snack food (initial)
Mass of filter paper
Mass of filter paper & snack food
Mass snack food (final)
Mass evaporating dish
Mass evaporating dish & fat
Mass fat

 

Table 2: % Fat in Snack Food

Group #	Snack Food	% Fat
1	Ruffles
2	Ruffles
3	Ruffles
4	Light
5	Light
6	Light
7	Light
8	Light

 

B.     Calculations:

1.A) Calculate the mass of the snack food after filtration.

B) and the mass of fat after evaporation.

2.Calculate the difference between the original mass of the snack food and the mass after of the snack food and the mass after filtration. (This difference is the mass of the extracted fat.)

3.Calculate the percent by mass of the fat in the snack food, using the following formula: % Fat= mass of fat (1 b) / original mass of food x100

Record in Table 2

4.Calculate the estimate of the number of dietary calories produced in the digestion of the fat in this snack food sample.

5.Convert the dietary calories (DC) for your sample size to DC based in your serving size. This is your DC from the digestion of fat.

6.Calculate the percentage of calories from fat.

% cal from fat = DC from digestion of fat / total DC (from package) x 100

7.RSD for each snack food.

C.    Graphs: % Fat in Ruffles: X-axis= types of Chips Y-axis= % Fat

D.    Questions

1.If you tested both “light” and regular snack foods, was there a significant difference in the fat content. Explain.

2.Discuss how did the amount fat calculated compared to the amount recovered by evaporation.

 IV.            Conclusion:

*Note: The snack food does not have to be the chips I used.

Laboratory Techniques

       I.            Objectives: The objective is to learn to take mass, volume, and temperature and also to learn separation techniques.

    II.            Materials & Procedures:

A.    Materials:

-Balance          -Graduated Cylinder   -Salt (appr. 1 g.)          -Thermometer Clamp

-Beakers          -Hot Plate        -Sand (appr. 1 g.)        -Watch Glass   -Filter Paper

-Iron Ring       -Stirring Rod   -Water     -Funnel        -Ring Stand     -Thermometer

B.     Procedures:

1.Obtain a sample of salt. Take a small beaker and place it on the balance pan. Hit the tare button. Add the salt to the beaker. Record the mass to the nearest hundredth of a gram in Table 1.

2.Obtain a sample of sand. Using the beaker with salt, place it on the balance pan and hit the tare button. Add the sand to the beaker. Record the mass to the nearest hundredth of a gram in Table 1.

3.Fill your 100 ml graduated cylinder approximately ½ full of water. Record the volume to the nearest tenth of a ml in Table 1.

4.Add the water to the beaker with the sand and salt. Stir the contents until the salt has completely dissolved.

5.Measure the mass of a piece of filter paper to the nearest hundredth of a gram. Record in Table 1.

6.Measure the mass of a beaker to the nearest hundredth of a gram. Record in Table 1.

7.Set up a filtration apparatus using the pre-massed filter paper and beaker. Pour the mixture into the funnel collecting the filtrate in the pre-massed beaker and the sediment in the pre-massed filter paper.

8.Rinse the sediment twice with a small amount of distilled water.

9.Set up hot plate, ring stand, thermometer and thermometer clamp. Measure the initial temperature of the filtrate. Record the temperature to the nearest tenth of a degree in Table 2.

10.                    Begin heating the filtrate and record the temperature every 10 minutes. Record each temperature in Table 2.

11.                    Remove the thermometer and place the watch glass on the beaker. Continue to heat until the liquid is driven off and only the solid remains.

12.                    Let the beaker cool. Record the mass to the nearest hundredth of a gram. Record in Table 1.

13.                    Remove the filter paper and sediment from the funnel. Place the filter paper on several layers of paper towels. Place aside and let dry over night. The next day record the mass to the nearest hundredth of a gram in Table 1.

C.     Safety:

 III.            Analysis

A.    Data:

Table 1: Measurement

Object	Measurement
Mass of Salt (initial)
Mass of Sand (initial)
Volume of Water
Mass of Filter Paper
Mass of Filter Paper & Sand
Mass of Sand (final)
Mass Ev. Dish & Water Glass
Mass Dish, Glass, Salt
Mass of Salt (final)

 

Table 2: Temperature

Time (minutes)	Temperature (degrees C)
0
1
2
3
4
5
6
7
8
9
10

 

B.     Calculations

% Error Salt                True Value: 1.57

%RSD Salt

%Error Sand               True Value: 1.19

%RSD Sand

C.     Graphs: Salt Water Temperature Over Time X-axis= time Y-axis=Temperature

 IV.            Conclusion

Density Lab

     

       I.            Objectives: The objectives of this lab are to determine the densities of different objects and liquids.

    II.            Materials & Procedures:

A.    Materials: solid sample, balance, graduated cylinder, water, weighing pan, ethanol

B.     Procedures:

1.Measure the length and diameter of 5 pieces of your sample to the nearest 0.01cm. Record in Table 1. Calculate the volume of each sample and record in Table 1.

2.Measure the mass of each sample and record to the nearest 0.01g. Record in Table 1.

3.Calculate the density of each sample from the data for volume by this method.

4.Measure the volume of the sample using the water displacement method. Record the volumes to the nearest 0.1ml in Table 1.

5.Calculate the density of each sample using the volume measured by the water displacement method.

6.Place your 10ml graduated cylinder on the balance pan and press the tare/zero button. Add ethanol to the cylinder until its ½ to ¾ full. Record the mass in Table 2.

7.Place the cylinder flat on your lab bench and read the volume. Record the volume in Table 2.

8.Pour out the ethanol and repeat steps 6 & 7 five more times using different volumes of ethanol.

9.Pour the ethanol down the drain with plenty of water.

10.                    Calculate the density for each trial

11.                    Clean up!

C.     Safety:

 III.            Analysis:

A.    Data

Table 1- Density of Tecaform

Measurement	Trial 1	Trial 2	Trial 3	Trial 4	Trial 5
Length (cm)
Diameter (cm)
Radius (cm)
Volume (cm3)
Mass (g)
Density (g/cm3)
Vi Water (ml)
Vf Water (ml)
Volume (ml)
Density (g/ml)

 

Table 2- Density of Ethanol

Measurement	Trial 1	Trial 2	Trial 3	Trial 4	Trial 5
Mass of Ethanol (g)
Volume of Ethanol (ml)
Density (g/ml)

 

B.     Percent Error

1.Percent error tecaform regular method. (True Value: 1.40)

2.Percent error tecaform water displacement. (True Value: 1.40)

3.Percent error ethanol. (True Value: 0.789)

C.     Graphs

1.Density of tecaform by measurements. X-axis= volume (cm³) Y-axis= mass (g)

2.Tecaform by water displacement. X-axis= volume (cm³) Y-axis= mass (g)

3.Density of Ethanol. X-axis= volume (cm³) Y-axis= mass (g)

D.    Questions

1.Most students find that their results for the determination of their solid’s densities are worse than their results for the determination of Ethanol’s density. Explain why this is probably true.

2.Does the density of an object depend on its sample size? Explain.

3.The density of an object can be used to help identify a substance. Explain how you could distinguish between two substances that have densities that are very, very close to each other.

4. Is the density a physical or chemical properly of matter? Explain.

5.Could you use the method used to determine the volume of your solid for all solids? Explain.

6.Is density an intensive or extensive property? Explain.

7.Calculate the slope of each line on your graphs. What does the slope represent? Explain.

 IV.            Conclusion: