Question

 

1. Obtain a benzoic acid pellet, determine the mass of the pellet on the analytical balance and record the mass in your hard covered note book. The error for the analytical balance is  0.0005 g. Attach approximately 10.0 cm of fuse wire as shown by your Instructor (use the length of the card that holds the fuse wire, the card is already calibrated in heat units, cal or 4.18 J units) and adjust it to give firm contact with the benzoic acid pellet. Avoid kinks in the fuse wire.

2. Carefully assemble the bomb, keeping surfaces of closure scrupulously clean. Dismantled parts should be placed on a clean, dry paper towel. Place the bomb on the bench next to the O2 cylinder. Tighten cover by hand. The Instructor must assist you in connecting the bomb to the O2 cylinder, and slowly admit oxygen to a final pressure of 20 atm (280 psi.) Close valves on cylinder. Relieve pressure in line by means of the black knob on the regulator. Remove the gas coupling and check the circuit again.

3. Place the bomb in the calorimeter and make sure the ignition wires are connected properly. Carefully fill the inner reservoir in the calorimeter with 2000 mL distilled water, using the volumetric flask provided. The water should completely cover the bomb; no oxygen bubbles should escape from the bomb if the seal is good. If there is a substantial leak, the bomb should be dried and refilled with oxygen. Small leaks are insignificant.

4. Connect the motor and pulley experiment with the o-ring provided and starts the stirrer. Connect the leads on the outside of the bomb jacket to the 10 cm fuse in the igniter

. 5. Turn on the stirrer. For this, data points should be collected every ten seconds up to a total of 150 data points.

6. After at least 12 data points have been collected, and the temperature is reasonably constant or shows only a small up- or downward trend, press and hold the ignition button on the ignitor for approximately 1second. You will see the red light on the ignition box flash on and off again, showing that the fuse wire has burned. You should NOT be standing over the bomb while igniting the bomb!! Stand back from the bomb for at least 15 seconds. If combustion has occurred, the temperature will start to rise within the next two or three data points.

7. Keep recording data until the 150 points finishes.

8. Remove the bomb from the calorimeter and relieve the pressure by opening the valve. BE SURE to open the release valve before trying to unscrew the top of the bomb! 9. Measure the remaining length of unoxidized fuse wire. (This information is needed to correct for its heat of combustion). Carefully clean and dry the calorimeter and sample pan.

10. Repeat this procedure with the second benzoic acid pellet.

11. Once you have good data for benzoic acid, allowing you to calculate the calorimeter constant C, repeat the full procedure for each of the two sucrose samples.

Answer 1

Initially, using analytical balance weigh the benzoic acid pellet and note mass value in your record. Since, error in balance ± 0.0005 g attach the 10.0 cm of fuse wire as shown by your Instructor and proceed to weigh the benzoic acid pellet.
Precisely amass the bomb, keeping surfaces of conclusion conscientiously spotless. Destroyed parts ought to be set on a perfect, dry paper towel. Place the bomb on the seat beside the O2 barrel. Fix cover by hand. The Teacher must help you in interfacing the bomb to the O2 barrel, and gradually concede oxygen to a last weight of 20 atm (280 psi.) Close valves on chamber. Soothe weight in line by methods for the dark handle on the controller. Expel the gas coupling and check the circuit once more.
Place the bomb in the calorimeter and ensure the start wires are associated appropriately. Deliberately fill the internal repository in the calorimeter with 2000 mL refined water, utilizing the volumetric carafe gave. The water ought to totally cover the bomb; no oxygen air pockets should escape from the bomb if the seal is great. In the event that there is a considerable release, the bomb ought to be dried and refilled with oxygen. Little holes are immaterial.
Interface the engine and pulley explore different avenues regarding the o-ring gave and begins the stirrer. Interface the leads outwardly of the bomb coat to the 10 cm meld in the igniter.
Turn on the stirrer. For this, information focuses ought to be gathered at regular intervals up to an aggregate of 150 information focuses.
After no less than 12 information focuses have been gathered, and the temperature is sensibly consistent or demonstrates just a little up-or descending pattern, press and hold the start catch on the ignitor for around 1second. You will see the red light on the start box streak on and off once more, demonstrating that the wire has consumed. Try not to remain over the bomb while touching off the bomb!! Remain once more from the bomb for no less than 15 seconds. In the event that ignition has happened, the temperature will begin to ascend inside the following a few information focuses.
Continue recording information until the point when the 150 focuses wraps up.
Expel the bomb from the calorimeter and calm the weight by opening the valve. Make sure to open the discharge valve before endeavoring to unscrew the highest point of the bomb! 9. Measure the rest of the length of unoxidized combine wire. (This data is expected to adjust for its warmth of burning). Painstakingly spotless and dry the calorimeter and test container.
Rehash this strategy with the second benzoic corrosive pellet.
Repeat this procedure with the second benzoic acid pellet.
When you have great information for benzoic corrosive, enabling you to figure the calorimeter steady C, rehash the full system for each of the two sucrose tests.