Experiment 1: Ideal Gas Law - Finding Percent H2O2 with Yeast
Once the number of moles of O2 gas is calculated, the percent of H2O2 present in the solution can be determined.
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Materials (1) 250 mL Beaker |
3 in. Rigid Tubing |
*Camera/Smart phone is Sufficient *You Must Provide |
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Procedure
- Put on your safety glasses and gloves (provided in your safety box).
- Prepare the apparatus as shown in Figure 5. Insert the smaller rigid tubing into one end of the larger, flexible tubing. Insert the free end of the rigid tubing securely into the rubber stopper hole.
Caution: Be careful when working with rigid tubing. This tubing is made of glass and can break if excess force is applied. - Bend the free end of the flexible tubing into a U-shape and use a rubber band to hold this shape in place. This will allow you to more easily insert this end of the flexible tubing into the inverted graduated cylinder. Make sure the tubing is not pinched and that gas can flow freely through it.
- Fill the 100 mL graduated cylinder with distilled water slightly over the 100 mL mark.
- Fill the 500 mL beaker with 400 mL of distilled water.
- Take the temperature of the water in the 500 mL beaker and record it in Table 1. Also, determine the barometric pressure in the room and record it in Table 1.
Hint: If necessary, use the regional pressure as a close substitute to the room pressure. This can easily be found online - if necessary, convert this value to atm. - Mix 100 mL of warm water (45 °C) and one packet of baker's yeast in a 250 mL beaker. This will activate the yeast from the dormant state. Be sure to mix well with a stir rod until the yeast is completely dissolved.
Hint: Water must be between 42 - 47°C. Otherwise, you will kill the yeast (e.g., no activation). - Use a 10 mL graduated cylinder and pipette to measure 5 mL of hydrogen peroxide. Pour the hydrogen peroxide into the Erlenmeyer flask and securely place the stopper with stopper tube into the top of the Erlenmeyer flask.
- Clean the 10 mL graduated cylinder by rinsing it at least three times with tap water. Dispose of the rinse down the drain.
- Cover the opening of the graduated cylinder with two or three fingers and quickly turn it upside down into the 500 mL beaker already containing 400 mL of water. DO NOT remove your fingers from the opening until the graduated cylinder is fully submerged under the water. If the amount of trapped air exceeds 10 mL, refill the cylinder and try again.
- Insert the U-shaped flexible tubing into the beaker, and carefully snake it into the submerged opening of the graduated cylinder. You want as little air as possible to be in the graduated cylinder.
- Secure the graduated cylinder to the ring stand by sliding a ring over the base of the submerged cylinder, then securing the ring to the stand.
- With the cylinder vertical, record the volume of air inside (the line at which the water reaches in the cylinder) in Table 1. Take a picture of the graduated cylinder containing the water using your camera (or smart phone) for submission to your instructor.
- Using the pipette, measure out 5 mL of yeast solution into the rinsed 10 mL graduated cylinder.
Note: Do not immediately pour the yeast solution into the Erlenmeyer flask. - Remove the stopper (still connected to the hose) from the Erlenmeyer flask. Reset the stopwatch.
- Quickly pour the 5 mL of yeast solution into the Erlenmeyer flask. Immediately place the stopper securely in the opening of the Erlenmeyer flask by twisting it down into the flask gently.
- Start timing the reaction with the stopwatch.
- Swirl the Erlenmeyer flask to mix the two solutions together.
- Bubbles will begin to form in the 100 mL graduated cylinder.
Hint: If gas bubbles are not immediately visible, make sure the stopper is on tight enough and the tubing is not leaking. You will need to start over after correcting any problems. - Continue to swirl the Erlenmeyer flask and let the reaction run until no more bubbles form (to assure the reaction has gone to completion).
- Use your camera (or smart phone) to take a picture of the graduated cylinder after the water has been displaced. Be sure to correctly label the pictures and send it to your instructor along with your data tables and the answers to the post-lab questions.
Hint: Catalase in the yeast works best around the temperature of the human body. You can speed the reaction up by warming the Erlenmeyer flask with your hands. - Record the time when the reaction is finished in Table 2, along with the final volume of air in Table 1. Remember to read it at eye-level and measure from the bottom of the meniscus.
Pour all other liquids down the drain and clean the labware.
Once the number of moles of O2 gas is calculated, the percent of H2O2 present in the solution can be determined.
|
|||||
|
Materials (1) 250 mL Beaker |
3 in. Rigid Tubing |
*Camera/Smart phone is Sufficient *You Must Provide |
|
|
Procedure
- Put on your safety glasses and gloves (provided in your safety box).
- Prepare the apparatus as shown in Figure 5. Insert the smaller rigid tubing into one end of the larger, flexible tubing. Insert the free end of the rigid tubing securely into the rubber stopper hole.
Caution: Be careful when working with rigid tubing. This tubing is made of glass and can break if excess force is applied. - Bend the free end of the flexible tubing into a U-shape and use a rubber band to hold this shape in place. This will allow you to more easily insert this end of the flexible tubing into the inverted graduated cylinder. Make sure the tubing is not pinched and that gas can flow freely through it.
- Fill the 100 mL graduated cylinder with distilled water slightly over the 100 mL mark.
- Fill the 500 mL beaker with 400 mL of distilled water.
- Take the temperature of the water in the 500 mL beaker and record it in Table 1. Also, determine the barometric pressure in the room and record it in Table 1.
Hint: If necessary, use the regional pressure as a close substitute to the room pressure. This can easily be found online - if necessary, convert this value to atm. - Mix 100 mL of warm water (45 °C) and one packet of baker's yeast in a 250 mL beaker. This will activate the yeast from the dormant state. Be sure to mix well with a stir rod until the yeast is completely dissolved.
Hint: Water must be between 42 - 47°C. Otherwise, you will kill the yeast (e.g., no activation). - Use a 10 mL graduated cylinder and pipette to measure 5 mL of hydrogen peroxide. Pour the hydrogen peroxide into the Erlenmeyer flask and securely place the stopper with stopper tube into the top of the Erlenmeyer flask.
- Clean the 10 mL graduated cylinder by rinsing it at least three times with tap water. Dispose of the rinse down the drain.
- Cover the opening of the graduated cylinder with two or three fingers and quickly turn it upside down into the 500 mL beaker already containing 400 mL of water. DO NOT remove your fingers from the opening until the graduated cylinder is fully submerged under the water. If the amount of trapped air exceeds 10 mL, refill the cylinder and try again.
- Insert the U-shaped flexible tubing into the beaker, and carefully snake it into the submerged opening of the graduated cylinder. You want as little air as possible to be in the graduated cylinder.
- Secure the graduated cylinder to the ring stand by sliding a ring over the base of the submerged cylinder, then securing the ring to the stand.
- With the cylinder vertical, record the volume of air inside (the line at which the water reaches in the cylinder) in Table 1. Take a picture of the graduated cylinder containing the water using your camera (or smart phone) for submission to your instructor.
- Using the pipette, measure out 5 mL of yeast solution into the rinsed 10 mL graduated cylinder.
Note: Do not immediately pour the yeast solution into the Erlenmeyer flask. - Remove the stopper (still connected to the hose) from the Erlenmeyer flask. Reset the stopwatch.
- Quickly pour the 5 mL of yeast solution into the Erlenmeyer flask. Immediately place the stopper securely in the opening of the Erlenmeyer flask by twisting it down into the flask gently.
- Start timing the reaction with the stopwatch.
- Swirl the Erlenmeyer flask to mix the two solutions together.
- Bubbles will begin to form in the 100 mL graduated cylinder.
Hint: If gas bubbles are not immediately visible, make sure the stopper is on tight enough and the tubing is not leaking. You will need to start over after correcting any problems. - Continue to swirl the Erlenmeyer flask and let the reaction run until no more bubbles form (to assure the reaction has gone to completion).
- Use your camera (or smart phone) to take a picture of the graduated cylinder after the water has been displaced. Be sure to correctly label the pictures and send it to your instructor along with your data tables and the answers to the post-lab questions.
Hint: Catalase in the yeast works best around the temperature of the human body. You can speed the reaction up by warming the Erlenmeyer flask with your hands. - Record the time when the reaction is finished in Table 2, along with the final volume of air in Table 1. Remember to read it at eye-level and measure from the bottom of the meniscus.
Pour all other liquids down the drain and clean the labware.
Once the number of moles of O2 gas is calculated, the percent of H2O2 present in the solution can be determined.
|
|||||
|
Materials (1) 250 mL Beaker |
3 in. Rigid Tubing |
*Camera/Smart phone is Sufficient *You Must Provide |
|
|
Procedure
- Put on your safety glasses and gloves (provided in your safety box).
- Prepare the apparatus as shown in Figure 5. Insert the smaller rigid tubing into one end of the larger, flexible tubing. Insert the free end of the rigid tubing securely into the rubber stopper hole.
Caution: Be careful when working with rigid tubing. This tubing is made of glass and can break if excess force is applied. - Bend the free end of the flexible tubing into a U-shape and use a rubber band to hold this shape in place. This will allow you to more easily insert this end of the flexible tubing into the inverted graduated cylinder. Make sure the tubing is not pinched and that gas can flow freely through it.
- Fill the 100 mL graduated cylinder with distilled water slightly over the 100 mL mark.
- Fill the 500 mL beaker with 400 mL of distilled water.
- Take the temperature of the water in the 500 mL beaker and record it in Table 1. Also, determine the barometric pressure in the room and record it in Table 1.
Hint: If necessary, use the regional pressure as a close substitute to the room pressure. This can easily be found online - if necessary, convert this value to atm. - Mix 100 mL of warm water (45 °C) and one packet of baker's yeast in a 250 mL beaker. This will activate the yeast from the dormant state. Be sure to mix well with a stir rod until the yeast is completely dissolved.
Hint: Water must be between 42 - 47°C. Otherwise, you will kill the yeast (e.g., no activation). - Use a 10 mL graduated cylinder and pipette to measure 5 mL of hydrogen peroxide. Pour the hydrogen peroxide into the Erlenmeyer flask and securely place the stopper with stopper tube into the top of the Erlenmeyer flask.
- Clean the 10 mL graduated cylinder by rinsing it at least three times with tap water. Dispose of the rinse down the drain.
- Cover the opening of the graduated cylinder with two or three fingers and quickly turn it upside down into the 500 mL beaker already containing 400 mL of water. DO NOT remove your fingers from the opening until the graduated cylinder is fully submerged under the water. If the amount of trapped air exceeds 10 mL, refill the cylinder and try again.
- Insert the U-shaped flexible tubing into the beaker, and carefully snake it into the submerged opening of the graduated cylinder. You want as little air as possible to be in the graduated cylinder.
- Secure the graduated cylinder to the ring stand by sliding a ring over the base of the submerged cylinder, then securing the ring to the stand.
- With the cylinder vertical, record the volume of air inside (the line at which the water reaches in the cylinder) in Table 1. Take a picture of the graduated cylinder containing the water using your camera (or smart phone) for submission to your instructor.
- Using the pipette, measure out 5 mL of yeast solution into the rinsed 10 mL graduated cylinder.
Note: Do not immediately pour the yeast solution into the Erlenmeyer flask. - Remove the stopper (still connected to the hose) from the Erlenmeyer flask. Reset the stopwatch.
- Quickly pour the 5 mL of yeast solution into the Erlenmeyer flask. Immediately place the stopper securely in the opening of the Erlenmeyer flask by twisting it down into the flask gently.
- Start timing the reaction with the stopwatch.
- Swirl the Erlenmeyer flask to mix the two solutions together.
- Bubbles will begin to form in the 100 mL graduated cylinder.
Hint: If gas bubbles are not immediately visible, make sure the stopper is on tight enough and the tubing is not leaking. You will need to start over after correcting any problems. - Continue to swirl the Erlenmeyer flask and let the reaction run until no more bubbles form (to assure the reaction has gone to completion).
- Use your camera (or smart phone) to take a picture of the graduated cylinder after the water has been displaced. Be sure to correctly label the pictures and send it to your instructor along with your data tables and the answers to the post-lab questions.
Hint: Catalase in the yeast works best around the temperature of the human body. You can speed the reaction up by warming the Erlenmeyer flask with your hands. - Record the time when the reaction is finished in Table 2, along with the final volume of air in Table 1. Remember to read it at eye-level and measure from the bottom of the meniscus.
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Rating:
5/
Solution: Lab8 Experiment 1 lab