Chem Lab.
Objectives:
1. To make careful measurements of the amounts of each reactant.
2. To calculate the number of moles of each reactant.
3. To predict which reactant is in excess.
4. To use drawings to relate microscopic events, to write a chemical equation that represent those microscopic events.
5. To learn how to measure the volume of a liquid using a buret.
Prelab Questions:
1. Calculate the number of moles in 2.65g of zinc.
2. Calculate the number of moles of hydrochloric acid in 37.5mL of a 3.00M HCl solution.
3. Calculate how many moles of HCl are required to react with 0.244 moles of zinc.
Procedure:
1. Put on safety equipment.
2. Label small glass vial so your group can identify it later.
3. Determine the mass of the clean dry vial and record your mass to 2 decimal places on your lab sheet.
4. Zero the balance.
5. Add 3-4 grams of zinc to the vial and determine the mass of the zinc. Record on your lab sheet.
6. Go to one of the burets set up around the classroom.
7. Look at the buret and record the volume on your lab sheet.
8. Add 10 to 15mL of acid to your vial and record the ending volume on your lab sheet.
9. Make a drawing in the space provided of the vial and its contents on the lab sheet. Be sure to label all the chemicals present in the vial.
10. Store the vial in the beaker provided so the vial remains in an upright position.
11. Clean up lab station.
12. Allow vial to sit overnight.
13. Observe your vial and the contents. Make a drawing in the space provided of the vial and its contents and label all chemicals.
14. Dispose of the vial as instructed.
Data:
Mass of clean dry vial 14.95 grams
Mass of clean dry vial and zinc 18.65 grams
Initial buret reading of 3M HCl 1.88mL
Final buret reading of 3M HCl 17.91mL
After the hydrochloric acid was added to the zinc bubbles began to form as hydrogen gas was produced. By the second day, the bubbles had ceased forming and the zinc
1. To make careful measurements of the amounts of each reactant.
2. To calculate the number of moles of each reactant.
3. To predict which reactant is in excess.
4. To use drawings to relate microscopic events, to write a chemical equation that represent those microscopic events.
5. To learn how to measure the volume of a liquid using a buret.
Prelab Questions:
1. Calculate the number of moles in 2.65g of zinc.
2. Calculate the number of moles of hydrochloric acid in 37.5mL of a 3.00M HCl solution.
3. Calculate how many moles of HCl are required to react with 0.244 moles of zinc.
Procedure:
1. Put on safety equipment.
2. Label small glass vial so your group can identify it later.
3. Determine the mass of the clean dry vial and record your mass to 2 decimal places on your lab sheet.
4. Zero the balance.
5. Add 3-4 grams of zinc to the vial and determine the mass of the zinc. Record on your lab sheet.
6. Go to one of the burets set up around the classroom.
7. Look at the buret and record the volume on your lab sheet.
8. Add 10 to 15mL of acid to your vial and record the ending volume on your lab sheet.
9. Make a drawing in the space provided of the vial and its contents on the lab sheet. Be sure to label all the chemicals present in the vial.
10. Store the vial in the beaker provided so the vial remains in an upright position.
11. Clean up lab station.
12. Allow vial to sit overnight.
13. Observe your vial and the contents. Make a drawing in the space provided of the vial and its contents and label all chemicals.
14. Dispose of the vial as instructed.
Data:
Mass of clean dry vial 14.95 grams
Mass of clean dry vial and zinc 18.65 grams
Initial buret reading of 3M HCl 1.88mL
Final buret reading of 3M HCl 17.91mL
After the hydrochloric acid was added to the zinc bubbles began to form as hydrogen gas was produced. By the second day, the bubbles had ceased forming and the zinc