Question #bfcbb

1 Answer
May 19, 2017

Answer:

#3.8 * 10^(-21)"g"#

Explanation:

Copper has a molar mass of #"63.546 g mol"^(-1)#, which means that #1# mole of copper has a mass of #"63.546 g"#.

Now, in order to have #1# mole of copper, you need to have #6.022 * 10^(23)# atoms of copper #-># this is known as Avogadro's constant.

So, right from the start, you can say that if #1# mole of copper has a mass of #"63.546 g"# and #1# mole of copper contains #6.022 * 10^(23)# atoms of copper, then

#6.022 * 10^(23)color(white)(.)"atoms Cu " -> " 63.546 g"#

All you have to do now is to use this as a conversion factor to calculate the mass of #6# atoms of copper

#6 color(red)(cancel(color(black)("atoms Cu"))) * "63.546 g"/(6.022 * 10^(23)color(red)(cancel(color(black)("atoms Cu")))) = color(darkgreen)(ul(color(black)(3.8 * 10^(-21)color(white)(.)"g")))#

I'll leave the answer rounded to two sig figs.