# Equilibrium Calculation and Free Energy Change

Procedure 2

Determination of Kub

1. Obtain a 250 mL Beaker from the glassware shelf and place it on the lab bench.

√

2. Add 3-5 grams of solid urea to the beaker; once again the actual amount used is less important that knowing and recording the amount used.

Added 3g of urea

3. Attach a thermometer to the beaker, and note the initial temperature of the system

Initial Temperature 21.00C

4. Obtain a burette from the labware shelf and place it on the lab bench.

√

5. Fill the burette with 50 mL of water.

√

6. Link the burette and beaker containing urea together by the dragging the beaker of the burette, and dropping it in the burette?s approximate mid-point.

√

7. Open up the properties window and click on the burette. The properties window should now provide information related to the burette. Click on the push pin icon in the properties window to lock the display on the burette.

√

8. Open up the data window, once it is open, click on the beaker. Data associated with the beaker, including the contents of the beaker, should be displayed in the data window. Click on the pushpin icon in the Data window to lock the data display on the beaker and its contents.

Chemicals inside CO(NH2)2

Solid Mass 3.000g

9. In the properties window, enter a drip rate of ?2? in the available space. It should indicate that 0.1 mL of water will be added to the beaker with each click. Begin adding water to the beaker by clicking the ?drop? icon.

√

10. While monitoring the Data window, add water only until the all the urea is dissolved, as indicated in the data window. Note the volume of water added to completely dissolve all the urea, making a saturated solution of urea.

√

11. Repeat this process two more times, beginning with a different mass of urea. After the urea has just dissolved record the final temperature.

Added 3g of Solid Urea

Beaker: 50mL and a Solid Volume of 2.26mL before adding 0.1 drops of H2O with a starting temperature of 21.00C

Chemical inside: CO(NH2)2 Solid Mass 3.000g

Results after adding 0.1 mL of H2O each time:

Solid/Liquid Volume Co(NH2)2 Solid Mass H2O added CO(NH2)2 Dissolved Mass C

2.36mL 2.892g .10mL 0.108g 21.00

2.50mL 2.784g .20mL 0.216g 21.00

2.62mL 2.67g .30mL 0.324g 21.00

2.74mL 2.56g .40mL 0.432g 21.00

2.86mL 2.460g .50mL 0.540g 21.00

2.98mL 2.352g .60mL 0.648g 21.00

3.10mL 2.244g .70mL 0.756g 20.97

3.22mL 2.13g .80mL 0.854g 20.96

3.34mL 2.028g .90mL 0.972g 20.94

3.46mL 1.920g 1.00mL 1.080g 20.92

3.58mL 1.182g 1.10mL 1.188g 20.90

3.70mL 1.704g 1.20mL 1.296g 21.00

3.82mL 1.59g 1.30mL 1.296g 20.98

3.94mL 1.488g 1.40mL 1.512g 20.96

4.06mL 1.380g 1.50mL 1.620g 20.93

4.18mL 1.272g 1.60mL 1.728g 20.91

4.30mL 1.164g 1.70mL 1.836g 21.00

4.42mL 1.056g 1.80mL 1.944g 20.98

4.54mL 0.948g 1.90mL 2.052g 20.96

4.66mL 0.840g 2.00mL 2.160g 20.94

4.78mL 0.732g 2.10mL 2.268g 20.92

4.90mL 0.624g 2.20mL 2.376g 20.90

5.02mL 0.516g 2.30mL 2.484g 21.00

5.14mL 0.408g 2.40mL 2.592g 20.98

5.26mL 0.300g 2.50mL 2.700g 20.96

5.38mL 0.192g 2.60mL 2.808g 20.95

5.50mL 0.084g 2.70mL 2.916g 20.93

Dissolved:

5.62mL 0g 2.80mL 3.00g 20.91

Added 4g of Solid Urea

Beaker: 50mL and a Solid Volume of 3.01mL before adding 0.1mL drops of H2O with a starting temperature of 21.00C

Chemical inside: CO(NH2)2 Solid Mass 4.000g

Results after adding 0.1 mL of H2O each time:

Solid/Liquid Volume Co(NH2)2 Solid Mass H2O added CO(NH2)2 Dissolved Mass C

3.13mL 3.892g .10mL 0.108g 21.00

3.25mL 3.784g .20mL 0.216g 21.00

3.37mL 3.367g .30mL 0.324g 21.00

3.49mL 3.568g .40mL 0.432g 21.00

3.61mL 3.460g .50mL 0.540g 20.99

3.73mL 3.352g .60mL 0.648g 20.99

3.85mL 3.244g .70mL 0.756g 20.98

3.97mL 3.136g .80mL 0.864g 20.96

4.09mL 3.028g .90mL 0.972g 20.95

4.21mL 2.920g 1.00mL 1.080g 20.93

4.33mL 2.812g 1.10mL 1.188g 20.92

4.45mL 2.704g 1.20mL 1.296g 20.90

4.57mL 2.596g 1.30mL 1.404g 21.00

4.69mL 2.488g 1.40mL 1.523g 20.98

4.82mL 2.380g 1.50mL 1.620g 20.96

4.93mL 2.272g 1.60mL 1.728g 20.94

5.05mL 2.164g 1.70mL 1.836g 20.91

5.17mL 2.056g 1.80mL 1.944g 20.91

5.29mL 1.948g 1.90mL 2.052g 20.92

5.41mL 1.840g 2.00mL 2.160g 20.98

5.53mL 1.732g 2.10mL 2.268g 20.96

5.65mL 1.624g 2.20mL 2.376g 20.94

5.77mL 1.516g 2.30mL 2.484g 20.93

5.89mL 1.408g 2.40mL 2.592g 20.91

6.02mL 1.300g 2.50mL 2.700g 20.92

6.14mL 1.192g 2.60mL 2.808g 20.98

6.26mL 1.084g 2.70mL 2.916g 20.97

6.38mL 0.976g 2.80mL 3.024g 20.95

6.50mL 0.868g 2.90mL 3.132g 20.94

6.62mL 0.760g 3.00mL 3.240g 20.92

6.74mL 0.652g 3.10mL 3.348g 20.91

6.86mL 0.544g 3.20mL 3.456g 21.00

6.98mL 0.436g 3.30mL 3.564g 20.99

7.10mL 0.328g 3.40mL 3.672g 20.97

7.22mL 0.220g 3.50mL 3.780g 20.96

7.34mL 0.112g 3.60mL 3.888g 20.94

7.46mL 0.004g 3.70mL 3.996g 20.93

Dissolved:

7.56mL 0.000g 3.80mL 4.000g 20.92

Added 5g of Solid Urea

Beaker: 50mL and a Solid Volume of 3.76mL before adding 0.1mL drops of H2O with a starting temperature of 21.00C

Chemical inside: CO(NH2)2 Solid Mass 5.000g

Results after adding 0.1 mL of H2O each time:

Solid/Liquid Volume Co(NH2)2 Solid Mass H2O added CO(NH2)2 Dissolved Mass C

3.88mL 4.892g 0.10mL 0.108g 21.00

4.00mL 4.784g 0.20mL 0.216g 21.00

4.12mL 4.676g 0.30mL 0.324g 21.00

4.24mL 4.568g 0.40mL 0.432g 21.00

4.36mL 4.460g .050mL 0.540g 21.00

4.48mL 4.352g 0.60mL 0.648g 20.99

4.60mL 4.244g 0.70mL .0756g 20.98

4.72mL 4.136g 0.80mL 0.864g 20.97

4.84mL 4.028g 0.90mL 0.972g 20.95

4.96mL 3.920g 1.00mL 1.080g 20.94

5.08mL 3.812g 1.10mL 1.188g 20.92

5.20mL 3.704g 1.20mL 1.296g 20.91

5.32mL 3.596g 1.30mL 1.404g 20.92

5.44mL 3.488g 1.40mL 1.512g 20.98

5.56mL 3.380g 1.50mL 1.620g 20.96

5.68mL 3.272g 1.60mL 1.728g 20.94

5.80mL 3.164g 1.70mL 1.836g 20.93

5.92mL 3.056g 1.80mL 1.944g 20.91

6.05mL 2.948g 1.90mL 2.052g 20.92

6.17mL 2.840g 2.00mL 2.160g 20.98

6.28mL 2.732g 2.10mL 2.268g 20.97

6.41mL 2.624g 2.20mL 2.376g 20.95

6.53mL 2.516g 2.30mL 2.484g 20.93

6.65mL 2.408g 2.40mL 2.593g 20.91

6.77mL 2.300g 2.50mL 2.700g 21.00

6.89mL 2.192g 2.60mL 2.808g 20.98

7.01mL 2.084g 2.70mL 2.916g 20.97

7.13mL 1.976g 2.80mL 3.024g 20.95

7.25mL 1.868g 2.90mL 3.132g 20.93

7.37mL 1.868g 3.00mL 3.240g 20.92

7.49mL 1.652g 3.10mL 3.348g 20.90

7.61mL 1.544g 3.20mL 3.456g 20.92

7.73mL 1.436g 3.30mL 3.564g 20.98

7.85mL 1.328g 3.40mL 3.672g 20.97

7.97mL 1.220g 3.50mL 3.780g 20.95

8.09mL 1.112g 3.60mL 3.888g 20.94

8.21mL 1.004g 3.70mL 3.996g 20.93

8.33mL 0.896g 3.80mL 4.104g 20.92

8.45mL 0.788g 3.90mL 4.212g 20.90

8.57mL 0.680g 4.00mL 4.320g 20.92

8.60mL 0.572g 4.10mL 4.428g 20.99

8.81mL 0.464g 4.20mL 4.536g 20.97

8.93mL 0.356g 4.30mL 4.644g 20.96

9.05mL 0.248g 4.40mL 4.752g 20.95

9.17mL 0.140g 4.50mL 4.860g 20.93

9.29mL 0.32g 4.60mL 4.968g 20.92

Dissolved:

9.40mL 0.00g 4.70mL 5.000g 20.94

Assignment 1 of Procedure 2

1. Calculate the equilibrium constant Keq by dividing number of moles of urea in the system by total volume of water added to the beaker in L.

Assignment 2 of Procedure 2

Calculation of ?G and ?S

1. Calculate the free energy change of the dissolution reaction using the following formula:

?G = -RT lnKub

where R is the gas constant (8.31451 J K-1 mol-1) and T is the temperature in Kelvin.

2. Using the values of ??, ?G, and the temperature of the saturated solution, calculate ?S using the equation for Gibb?s Free Energy.

© BrainMass Inc. brainmass.com October 10, 2019, 12:48 am ad1c9bdddfhttps://brainmass.com/chemistry/energetics-and-thermodynamics/equilibrium-calculation-free-energy-change-308161

#### Solution Preview

Procedure 2

Determination of Kub

1. Obtain a 250 mL Beaker from the glassware shelf and place it on the lab bench.

√

2. Add 3-5 grams of solid urea to the beaker; once again the actual amount used is less important that knowing and recording the amount used.

Added 3g of urea

3. Attach a thermometer to the beaker, and note the initial temperature of the system

Initial Temperature 21.00C

4. Obtain a burette from the labware shelf and place it on the lab bench.

√

5. Fill the burette with 50 mL of water.

√

6. Link the burette and beaker containing urea together by the dragging the beaker of the burette, and dropping it in the burette?s approximate mid-point.

√

7. Open up the properties window and click on the burette. The properties window should now provide information related to the burette. Click on the push pin icon in the properties window to lock the display on the burette.

√

8. Open up the data window, once it is open, click on the beaker. Data associated with the beaker, including the contents of the beaker, should be displayed in the data window. Click on the pushpin icon in the Data window to lock the data display on the beaker and its contents.

Chemicals inside CO(NH2)2

Solid Mass 3.000g

9. In the properties window, enter a drip rate of ?2? in the available space. It should indicate that 0.1 mL of water will be added to the beaker with each click. Begin adding water to the beaker by clicking the ?drop? icon.

√

10. While monitoring the Data window, add water only until the all the urea is dissolved, as indicated in the data window. Note the volume of water added to completely dissolve all the urea, making a saturated solution of urea.

√

11. Repeat this process two more times, beginning with a different mass of urea. After the urea has just dissolved record the final temperature.

Added 3g of Solid Urea

Beaker: 50mL and a Solid Volume of 2.26mL before adding 0.1 drops of H2O with a starting temperature of 21.00C

Chemical inside: CO(NH2)2 Solid Mass 3.000g

Results after adding 0.1 mL of H2O ...

#### Solution Summary

Here the appropriate equations and mathematical solutions are provided step by step. Different values can easily be substiuted.