Question

A chemist weighed out 3.89 g of nickel. What is the number of moles of nickel she weighed out?

Answer 1

She measured out 0.0663 mol of nickel.

Explanation:

For this question, we need to use the Periodic Table to find the molar mass of `"Ni"` (58.69 g/mol).

The formula for molar mass is

`color(blue)(|bar(ul(color(white)(a/a) "molar mass" = "mass"/"moles"color(white)(a/a)|)))" "`

We can rearrange the formula to read

`"moles" = "mass"/"molar mass"`

∴ `"moles" = 3.89 color(red)(cancel(color(black)("g Ni"))) × "1 mol Ni"/(58.69 color(red)(cancel(color(black)("g Ni")))) = "0.0663 mol Ni"`