2014-2015 Lab Quiz A

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1. What is the chemical formula for barium hydroxide ________________________, what phase (state of matter is it in the lab?

1. In the Observation of the Chemical Reaction lab, what is the chemical formula for calcium chloride dihydrate ________________________, what phase (state of matter) is it first in the lab?

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b) What instrument would you add to the lab to ensure that this would not happen if you did the experiment again (cant' say that I would read ruler correctly)?Explain why you chose this instrument.

b) What piece of lab equipment would you add to the lab to ensure that this would not happen if you did the experiment again (cant' say that I would read ruler correctly)?Explain why you chose this piece of equipment.

(covers Phase of Matter Lab, Observations of a Chemical Reaction Lab and Thickness of Aluminum Foil Lab)
Name:

Period:

Answer the following questions in a clear, concise manner and showing all work,

1. In the Observation of the Chemical Reaction lab, what is the chemical formula for calcium chloride dihydrate ________________________, what phase (state of matter) is it first in the lab?

 _______________________

2. Write the mass of the Aluminum foil you measured here, ___________________. Explain using your knowledge of Significant figures and lab equipment why you recorded this number.

3. In the Phase of Matter lab, what are you assuming about the hotplate so that you can say that total time (running time "water" is on hotplate) is equal to total energy (energy given from the hotplate to the "water")?

______________________________________________________________________

4. In the Observation of a Chemical Reaction Lab, If you still had a blue color to the filtrate, what does it mean and how can you fix it?

5. In the Thickness of Aluminum foil lab, I mistakenly determined the length of the aluminum foil GREATER than it actually was.
a) How does that affect the calculated Al foil thickness, explain (the calculations).

b) What piece of lab equipment would you add to the lab to ensure that this would not happen if you did the experiment again (cant' say that I would read ruler correctly)?Explain why you chose this piece of equipment.

6. You made elemental copper solid in the Observation of a Chemical Reaction lab. Please explain to me (in outline form) how you can add additional steps to get as pure a sample of copper as possible (i.e. if you were to weigh your copper, it would have as small a percent error as possible).