Percent Composition

By Jerome Gomez,2014-05-05 09:14
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Percent Composition

Percent Composition

    We can find the percent composition of anything! Sometimes it is in terms of volume such as 3% HO in hydrogen peroxide. At other times, it is in terms of particle count such as 10 ppm 22

    O necessary to sustain aquatic life in streams. In this lab we will investigate the percent 2

    composition by mass. Remember that to find the percent of something you need the amount of the factor you are measuring and the total.

    % Composition = Part / Whole x 100.

    Remember as a child how you loved those chocolate cookies with that smooth crème on the inside? You probably ate them in that age-old technique. Twist and they come apart. Now the rich crème is yours! Generations have licked the filling out and then eaten the chocolate wafers. What makes a great cookie: Lots of creamy filling! You have been hired to find out if name brand OREO? cookies have more filling than the generic cookies from Kroger, Publix, or Wal-Mart.

    Design a lab in which you measure the percent of the cookie that is filling. Think about all the parameters that are important in this lab:

    1. use of constants (C)

    2. independent (IV) and dependent variables (DV)

    3. Multiple testing (Remember you can use data from others as long as you are sure about

    their research technique)

    4. Hypothesis written in an IF …………………., THEN ………………… statement

    You will have 15 minutes to design an experiment to measure the factor in question. IF your experiment is approved, you will have the rest of the class to complete the experiment. Collect all data. Tonight you will write up a FORMAL LAB REPORT.

    Use the sample FORMAL LAB REPORT as a guide for what your group needs to include:

    1. Cover Page: Include title of lab and members of the group

    2. Introduction- explain why you conducted the experiment and what the lab is all about

    3. Experimental Design- describe the materials to be used in performing the experiment

    4. Hypothesis- what you expect will be the answer to the question asked when you decided

     to do the experiment.

    5. Procedure- describes how the experiment is to be carried out, step by step.

    6. Results-

    Use a Data Table to show the quantitative results of your experiment.

    Graph your data in the most clear and concise manner possible. A line graph is most

    appropriate in this case. Remember to use standard graph paper or use Excel, title the

    graph, label the x (independent variable) & y (dependent)-axes, and establish a scale

    for each axis.

    7. Conclusions- very important to state what you learned or concluded from performing

    the experiment. Discuss if the results matched your hypothesis.

    Popcorn- Does refrigeration help the popping


    Mr. Snyder


    My mother always told me that if I refrigerated the kernels, I would get more popped corn. In this experiment I hoped to learn whether refrigerating the unpopped kernels really gives better popcorn. I do not believe this to be true. If I refrigerated the kernels, then there will be no difference in the

    number of unpopped kernels after heating.

IV: Temperature of Kernels

    Cold Room

    5 Trials 5 Trials

DV: Number of unpopped kernels

     C: Brand of popcorn

     Weight of bag

     Time of cooking

     Setting on microwave


    A 3 oz bag of popcorn that was kept at room temperature was placed in a microwave set at 5. The bag was micro waved for 2 minutes. The bag was removed and immediately opened. The number of kernels un-popped was recorded as well as the number of popped kernels. The percentage of un-popped kernels was calculated. This was repeated 5 times. Similarly, the percentage of un-popped kernels were determined for popcorn that has been refrigerated for 24 hrs.


% un-popped



Temperature of Average % 1 2 3 4 5 kernel unpopped

    cold 6 7 10 12 8 8.6

    room 4 8 8 7 9 7.2

    % unpopped kernels as

    temperature varies




    7.5 @ 2 minmin


    % unpopped kernels kernels 6.5

    cold room

    temperature of unpopped kernels

    As shown by the graph, the kernels that had been refrigerated have a higher percentage of unpopped kernels than the room temperature kernels.


    The experiment tried to find out if it is true that refrigerating your popcorn enhances the popping process. The room temperature kernels actually popped better than those that were refrigerated. This did not support the hypothesis.

    Mr. Snyder found the same results when he did the experiment. The molecules of air trapped in the kernel were able to expand better if they were at room temperature. The gas molecules in the cold kernels would need extra heat in order to pop. Additional experiments could be conducted to determine if the results found here apply to all brands of popcorn. Improvements could be made in the experiment by determining the percent by mass of the un-popped corn to popped corn. A t-test could also be used to determine if the results are significant.

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