One carat is .20g, how many gold atoms are in one carat of gold?

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Answer 1 · 2018-04-12T14:11:36

#6.11 xx 10^20" atoms of gold"#

#"number of moles" = "mass" / "relative formula mass"#
#n = m/M_r#

Mass = #0.20#

#M_r# of gold = #197#

#n = 0.20/197 = 1/985# moles

#1# mole = #6.02 xx 10^23# atoms

#1/985# moles = #1/985 xx 6.02 xx 10^23# atoms

#= 6.1116... xx 10^20# atoms

#color(red)(~~ 6.11 xx 10^20" atoms of gold")#

(3 significant figures)