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Thread: Science Lab Report Help

  1. #1 Science Lab Report Help 
    New Member
    Join Date
    Oct 2010
    Hello I am a student that goes to High school and is looking towards a bright future. I've never asked for help before but here goes.

    Lab - Percent Composition
    Objective: To observe a chemical reaction, and to determine the percent
    composition by mass of the compound formed.
    1. Weigh the empty crucible.
    2. Take a sample of the magnesium ribbon (6). Record the mass of
    the ribbon and crucible.
    3. Position the crucible on the clay triangle. Cut the magnesium
    ribbon into 1/2 segments and place them inside the crucible.
    Light the Bunsen burner and cover the crucible. Heat the crucible
    until all the magnesium pieces stop glowing. (Lift the cover
    periodically to check the condition of the magnesium)
    4. Turn off the Bunsen burner and allow the crucible to cool on the
    asbestos pad.
    5. When the crucible is completely cool (after about 10 minutes)
    weigh the crucible and its contents again. Be careful not to
    spill the contents. Record the mass.
    6. Clean up your work area.
    Results and Data Analysis: (Present your results in a data table)
    (a) Mass of empty crucible = (b) Mass of magnesium =
    (c) Mass of magnesium and crucible = (d) Mass of the product =
    (e) Mass of the substance that reacted with the magnesium =
    Follow up:
    Based on your experimental evidence, answer the following questions.
    1. What evidence do you have that a chemical reaction took place?
    2. Classify the type of chemical reaction in this experiment.
    3. What substance did the magnesium react with?
    4. According to atomic theory, who determined that atoms of elements
    combine in fixed ratios to form new substances?
    5. What is the name of the compound, and which class does it belong to?
    6. Calculate the percent composition by mass (grams) of the compound
    Conclusion: Summarize your major findings.

    MY QUESTIONS: How do I find out what the reacted substance was?,
    Can someone help me with the questions?

    Here are my results:
    Mass of Empty Crucible without lid 22.96
    Mass of Empty Crucible with lid 34.6
    Mass of Magnesium 0.22
    Mass of Crucible with Magnesium and lid 34.72
    Mass of Crucible with Magnesium and without lid 23.17
    Mass of Substance that reacted with Magnesium 0.08
    Mass of Crucible with Magnesium and lid 34.79
    Mass of Crucible with Magnesium and without lid 23.24

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