Presentation Transcript

1. Conservation Law Matter cannot be created nor destroyed. Example: Burning match + oxygen = ash + smoke + gases
2. Practice
3. Practice Place a piece of paper towel on the balance. Measure out 3 g of baking soda. Measure out 10 mL of vinegar in a graduated cylinder. Transfer the vinegar to a beaker. Place the paper towel with baking soda and the beaker of vinegar on the balance and determine the combined mass and record it on your table as “initial mass”
4. Slowly pour the baking soda into the beakerthat contains the vinegara LITTLE at a time and gently swirl the contents. When the reaction is finished, put the paper towel and beaker back on the balance and determine the mass. Record this as “Final mass” Calculate the “Change in mass”
5. Evaluate the lab design Which products’ masses were not measured? How can you be sure to measure the masses of all of the reaction products? Design and conduct your lab using the same amounts of baking soda and vinegar.
6. Analysis Compare the changes in mass you calculated for the first and second trials. What value would you expect to obtain for a change in mass if both trials validated the law of conservation of mass? Was the law of conservation of mass violated in the first trial? Explain your reasoning. If the results of the second trial were different from those of the first trial, explain why. Suppose someone performs an experiment like the one you designed and fins that the final mass is much less than the initial mass. Would that prove that the law of conservation of mass is wrong? Explain your reasoning.