Chapter 1 Volume and Mass Experimental Write-ups


Exp. 1.4 Measuring Volume by Displacement of Water

II. Data and Observations

    Individual data:                                                                                                                                              

        -measurements                                                              
        -calculations.

    Class data table

III. Conclusion: Respond to the purpose of the experiment. Use portions of the purposes in your conclusion. Include the percentage of the dry sand that is actually sand.
               
IV. Discussion: Respond to the following questions. Skip a space between each response. Do not use pronouns unless used in the question.:

1. Describe what is actually being measured when dry sand is put into a graduated cylinder?
2. Add your volume measurement of dry sand to your volume measurement of water recorded in the experiment. Why isn't this volume sum the same as your measurement of the volume of sand and water mixed?
3. The actual percent of air space in this sand is 38%. Is your data accurate? Explain. (Describe how close your percentage value was.)
4. You all had different amounts of sand, yet you all should have obtained the same percentages. Explain why?


V.
Sources of Error

Say the sand was wet before it was poured into the graduated cylinder,                                

1. How would this affect the calculation of air space between the sand grains?
2. How would this affect the calculated percentage volume of sand that is air?






Exp. 1.1 Heating Baking Soda


Purpose: To determine...


Data and Observations
:

(Use a straight edge. Plan ahead. As neatly as you can, copy the following data tables into your lab notebook.)

Table 1. Observations of Heating Baking Soda

What was observed during/after heating?

(phrases only, not complete sentences)

Top of test tube

Bottom of test tube

Inverted bottle




Table 2. The Tea Test


Observations of tea mixed with baking soda

(phrases only, not complete sentences)


Unheated Baking Soda




Heated Baking Soda




Conclusion: Respond to the purpose. Include portions of the purpose in your response.


Discussion: Respond to the following questions in complete sentences.

Use part of the question in your response.

Skip a space between each question.

Do not use personal pronouns.

1. Identify the piece of equipment (or tool) that allowed any liquid produced from heating the baking soda to be observed?

2. Describe the piece(s) of equipment (or tools) that allowed any gas produced from heating the baking soda to be observed?

3. Read Figure 1.4 on p. 4 in your textbook. Explain the purpose or importance of heating an empty test tube.  

4. Think about the observations of the tea test. Could the unheated baking soda and the heated baking soda be the same substance? What is your evidence?


Sources of Error: Respond in complete sentences. Same guidelines apply as to discussion questions.

1. Imagine that there was a large air bubble in the bottle in the beginning of the experiment. How would this large air bubble affect the observed amount of gas in the bottle at the end of the experiment?




Exp. 1.8 The Sensitivity of a Balance


I. Purpose #1:
To model and define the sensitivity of the balance.


   Purpose #2: To determine if the mass of an object will be the same if the object is massed several times. In other words, how reliable and reproducible mass measurements are when made with a balance.

                  


II. Data and Observations:



                                       ______       mass (g)    ___            

                          trial #          penny                 rubber stopper

                          1

                          2

                          3

                          4

                          5


III. Conclusion

Respond to both purposes in complete sentences.


IV. Discussion  (Remember, Complete sentences and no personal pronouns.)

1. The "range" of a set of data refers to the lowest and the highest value collected. Indicate the range of the mass measurements collected, i.e. 2.56g - 2.58g for the penny and/or the stopper. 

         

2. "Precision" in chemistry refers to how consistent the data is. Did the data collected represent precision? Explain.

      

3. What is the smallest amount of mass that the electronic balances used in this experiment can detect?
       

4. Say two measurements for the mass of a stopper were 5.68 g and 5.67 g. Thinking about your response to question 3, would these two measurements be considered the same? Explain.



Sources of Error
1. A student collected several measurements for the mass of the penny that differed by roughly 5 grams.
Explain the most likely error that could have happened.










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