A typical atom has a diameter of about 1.0 10-10 m.

(a) What is this in inches?
in.


(b) How many atoms are there along a 23.0 cm line?
Atoms

To convert meters to inches I find it easiest to first convert meters to centimeters (by multiplying by 100), then divide by 2.54 cm/inch. Like this:


1 \times 10 ^ {-10}\ meters\ \times \ \frac {100\ cm} {meter}\ \times \ \frac {1\ inch} {2.54 cm}


Note that when you multiply this out all the meters and cm units cancel out ,leaving only inches.

For the second part, you can either (a) divide 23 cm by the diameter of the atom in cm, or (b) divide 0.23 meters by the diameter of the atom in meters. The point of this is simply to make sure that you keep the units of length consistent.

I'm trying to figure out how many inches are found in 0.1 to 0.5 nanometers (the typical diameter of an atom).

Use proportion.

1 m = 39.37008 in
1 m = 1 x 10^-9 nm

1 nm = ? In
0.1 nm = ? In
0.5 nm = ? In

Let me google that for you (http://lmgtfy.com/?q=how+many+inches+per+nanometer%3F)