If there are 7.44 x 10(23) atoms of gold, how many moles of gold are there?

Reviewing for a final. Went through some old quizzes to work on stuff I got wrong, and all my teacher did be circle it, and I don't understand what I did wrong.

1 Answer
Dec 16, 2017

Answer:

#=1.24molAu#

Explanation:

  1. Given then #eta "atom "Au=7.44xx10^23#, this value can be translated to #etaAu# through molar conversion.
  2. Knowing the mole relationship as shown below, is your equivalence statement. This is actually the Avogadro's number #(N_A)# also known as mole; thus,
    #1molAu=6.02x10^23 (N_A)"atoms "Au#
  3. From the given equivalence statement, two (2) conversion factors can be derived.
    #(1molAu)/(6.02xx10^23"atoms"Au) or (6.02xx10^23"atoms"Au)/(1molAu)#
  4. Choose the right conversion factor making sure that the unwanted unit are cancelled leaving the desired one.
    #=7.44xx10^23cancel("atoms"Au)xx(1molAu)/(6.02xx10^23cancel("atoms"Au))#
    #=(7.44xx10^23molAu)/(6.02xx10^23)#
    #=1.24molAu#