Question

How do I calculate mass loss per mm^2 given length, diameter, initial and final mass values?

I'm doing a chemistry lab, and I've been asked to calculate the mass loss per mm^2 for a large group of nails in which we've removed the zinc coating on. The values I have calculated so far are:

Average length: 39.09 mm
Ave. diameter: .22533 cm
Initial mass average: 1.1977 g
Final mass ave.: 1.062 g

I'm not asking anyone to do this entirely for me; rather, just to explain how I might go about solving it myself. Do I need to find the area of an average nail using length and diameter? Since only the outer coating was removed, is that effected at all by the calculation of this value? I'm confused on which of the 4 things I know I even need to find this. Thanks for your help! I really appreciate it.

Answer 1

Here's what I get.

`"Mass loss per square millimetre" = "mass loss"/"square millimetres"`

Step 1. Calculate the mass loss

`"Average mass loss = Initial mass average - Final mass average"`

Step 2. Calculate the average nail area in square millimetres

Use the formula for the area of a cylinder.

The ends of the nails are circles with `"area" = πr^2`.

The round surface of the nail is a rectangle with

`"area = length × width" = h × 2πr = 2πrh`

Step 3. Calculate the mass loss per square millimetre

The coating is so thin that it does not affect the dimensions of the nail.