Question #2eec6

1 Answer
Oct 19, 2017

Answer:

#"0.36292 moles"#

Explanation:

For starters, you already know that #1# mole of rubidium has a mass of #"85.4678 g"# because rubidium has a molar mass of #"85.4678 g mol"^(-1)#.

So if you know the mass of #1# mole of rubidium, you can use it as a conversion factor to figure out the number of moles needed to have #"31.018 g"#.

#31.018 color(red)(cancel(color(black)("g"))) * "1 mole Rb"/(85.4678color(red)(cancel(color(black)("g")))) = color(darkgreen)(ul(color(black)("0.36292 moles Rb")))#

The answer must be rounded to five sig figs, the number of sig figs you have for the mass of rubidium.