Mass Comparison Lab By: Nick L Jess F Sarah S Halle B

Purpose: To determine if there is a correlation between the mass of the reactants and the mass of the products in a chemical reaction. Hypothesis: As the mass of the reactants increases the mass of the products increases by a scale of 1 to 1.

Independent Variable: mass of the reactants Dependent Variable: mass of the products Control: first run- 1.0g of chemicals total

Repeated Trials: 6 Constants: Mass of glassware, same reactants, the same droppers for each chemical, and the same glassware for each trial.

Procedure: Part I 1. Place a beaker and two test tubes on the balance. 2. Add 0.5 grams to the mass of the glassware and add this amount of lead nitrate, Pb(NO3)2 to one test tube using a dropper. 3. Add 0.5 grams to the mass of the glassware and Pb(NO3)2, then add this amount of sodium iodide, NaI, to the second test tube using a dropper. 4. Record the mass of the glassware and the reactants in the data table. 5. Be sure that the arrow is aligned, then turn both test tubes over into the beaker to initiate the reaction. 6. Record the mass of the glassware and the products in the data table. 7. Repeat steps 1-6 using 1.0g, 1.5g and 2.0g of each reactant.

Procedure (continued) Part II 8. Complete the data table adding the results of your classmates. 9. Calculate the 5-number summary for the combined data (n=24).

Conclusion The data shows that there was no change in mass when lead nitrate and sodium iodide were mixed. This is because according to the law of consercation of mass, matter can neither be created nor destroyed. The variation of the data was all basically the same, one table had higher changes in mass but it is because they had a malfunctioning scale. The outliers in the data did not effect the overall change in mass which should have been 0g, the mean data of 1 gram (0.5g being lead nitrate and 0.5g being sodium iodide) of reactants was a changed of g. The mean data of 2.0 total grams of reactants was a change of g as well. For 3.0g of reactants the average change was 0.1g and for 4.0g of reactants the mean data was 0.33g. The mode of the data was 0.0g change and the median was also 0.0g. The range of the data was from -0.1g to 0.4g. Also 50% of the data lied between 0g and 0.1g.

Conclusion Continued The hypothesis in this lab was supported. The hypothesis stated that as the mass of reactants increases the mass of the products will increase by a ratio of 1:1. n the lab the data should have shown a 0.0g change in mass from the reactants to the product. If there was a change it was because of measuring mistakes or other problems. If more trials would have been conducted then the data would have shown more accurate results Mass is the amount of matter that something is made of. In this lab we measured the mass of the reactants and glassware, then compared it to the mass of the products and glassware. A chemical reaction is the process by which one or more substances undergo change to produce one or more different substances. We looked for signs of a chemical reaction to make sure that the substances reacted, so we could record any changes in mass. These signs may include color change, temperature change, and bubbling.