How many gold atoms are contained in 0.650 grams of gold?

1 Answer
Dec 8, 2015

Answer:

#"0.650 g Au"# contain #1.99xx10^21"atoms"#.

Explanation:

Calculate the moles of gold by dividing the given mass by its molar mass, #"196.966569 g/mol"# (atomic weight on periodic table in g/mol).

#(0.650cancel"g Au")/(196.966569 cancel"g"/"mol" "Au")="0.00330 mol Au atoms"#

#1 "mol atoms"=6.022xx10^23 "atoms"#

Multiply the calculated mol Au times #(6.022xx10^23"atoms")/(1"mol")#.

#0.00330cancel"mol Au"xx(6.022xx10^23"atoms")/(1cancel"mol")=1.99xx10^21 "atoms Au"#