Conservation of Mass

Aim: to determine if mass is conserved in a chemical reaction

Hypothesis:

PART A: I predict that the mass of the flask and vinegar will be quite a bit larger after the reaction with sodium bicarbonate

PART B: I predict that the mass of the flask, vinegar and balloon will be larger (by a little bit) after the reaction with the sodium bicarbonate

Materials:

• Balance

• Sodium bicarbonate

• Spatula

• Measuring cylinder

• Watch glass

• Balloon

• Conical flask x2

• Vinegar

Method:

PART A

1. Copy the results table for part A to record your results

2. Weigh 2.0g of sodium bicarbonate onto a watch glass

3. Add 20mL of vinegar to a flask

4. Ensure the balance is reading zero. Weigh the vinegar and flask. Record this mass (M1)

5. Predict whether the mass of the flask and vinegar after the reaction with the sodium bicarbonate will be more, less or the same than the initial mass

6. Add 2.0g of sodium bicarbonate (m2) to the flask containing the vinegar and swirl until the bubbling stops

7. Weigh the flask after the reaction has stopped. Record the final mass (M3)

PART B

1. Copy the results table for part B to record your results

2. Weigh 2.0g of sodium bicarbonate onto a watch glass

3. Add 20mL of vinegar to a flask

4. Ensure the balance is reading zero. Weigh the vinegar, flask and balloon. Record this mass (M1)

5. Predict whether the mass of the flask, balloon and vinegar after the reaction with the sodium bicarbonate will be more, less or the same than the initial mass

6. Add 2.0g of sodium bicarbonate (M2) to the flask and quickly stretch the balloon over the neck of the flask containing the vinegar and swirl until the bubbling stops

7. Weigh the flask after the reaction has stopped. Record the final mass (M3)

Results:

Part A:

Mass of flask and vinegar (M1)

Mass of sodium bicarbonate (M2)

Total mass before reaction (M1 + M2)

Mass after reaction (M3)

137.1g

2.0g

139.1g

139.0g

PART B:

Mass of flask, vinegar and balloon (M1)

Mass of sodium bicarbonate (M2)