Question

A chemist weighed out 8.72 g of tin. Calculate the number of moles of tin she weighed out.

Be sure your answer has the correct number of significant digits.

Answer 1

ans: 0.0735 mol

-to go from grams to moles we multiply:

grams (mol/grams)

-grams will cancel and we will be left with moles.

-Plug in your values; the atomic mass of tin (Sb) is 118.7g. (one mol of tin is equal to 118.7g):

8.72g (1 mol/118.7g) = 0.07346251

-since 1 mole of tin is equal to 118.7g, this is just like multiplying the initial value by 1; we are, in fact, not changing the number. Just converting to another unit of measure.

-round to the least number of significant digits (3 sig fig) and we end with 0.0735 mol.