Question

You and your lab partner are asked to determine the density of an aluminum bar. The mass is known accurately to 4 significant figures. You use a simple metric ruler to determine its size and calculate the results in column A. Your partner (using a precision micrometer for the first time) obtains the results in column B. (The accepted density of aluminum is 2.702 g/cm3.)

Method A results (g/cm3) Method B results (g/cm3)

2.2 2.603

2.3 2.601

2.7 2.605

2.4 2.611

Calculate the average density for each method.

Answer 1

Answer:

Average density for method A = 2.4 g/cm³

Average density for method B = 2.605 g/cm³

Explanation:

In order to calculate the average density for each method, we need to add the data for each method, and then divide the result by the number of measurements (in this case is 4 for both methods):

• For Method A:

Σ = 2.2 + 2.3 + 2.7 + 2.4 = 9.6

Average = 9.6/4 = 2.4 g/cm³

• For Method B:

Σ = 2.603 + 2.601 + 2.605 + 2.611 = 10.420

Average = 10.420/4 = 2.605 g/cm³