Chemistry Lab Skills

Which of the following are acceptable intervals on the graph axes?

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What is the maximum number of anomaly allowed in a graph?

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What is the minimum number of small squares that a plotted point be away from the best fit line before indicating that it is an anomaly?

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To how many decimal places should you record your pipette reading?

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To how many decimal places should you record your burette reading?

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"Calculate the percentage uncertainty of the volume measured"

Which of the following should be included in your answer?

• answers to 2 d.p.

• ±

• %

25.0 cm³ of X, 25.0 cm³ of Y, and 50.0 cm³ of Z were measured out using 50 cm³ measuring cylinders and all added into a conical flask. What is the total percentage uncertainty in the volume of the 100 cm³ mixture?

0.1g of NaCl was weighed using an analytical balance and was dissolved in 10cm3 of water, which was measured out using a 10cm³ measuring cylinder. The concentration of the solution is C g cm^-3. What is the uncertainty of the concentration?

(Note: uncertainty of each mass measurements is ±0.0005g)

• ±

  (0.0005/0.1) x 100%

  + (0.1/10) x 100%

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  (0.001/0.1) x 100%

  + (0.1/10) x 100%

• ±

  [(0.001 + 0.1)/ C] x 100%