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 0.0167g. The mean
data of 2.0 total grams of reactants was a change of 0.0167g 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.