Question #3da24

1 Answer
Jun 11, 2015

One atom of copper has a mass of #1.06 * 10^(-22)"g"#.
One gram of copper contains #9.47 * 10^(21)"atoms of copper"#


The be able to determine the mass of an individual copper atom, you need to use copper's molar mass.

Copper's molar mass expresses the mass of 1 mole of copper atoms. One mole of any substance contains exactly #6.022 * 10^(23)# atoms or molecules of that substance - this is known as Avogadro's number.

In your case, 1 mole of copper will contain #6.022 * 10^(23)# atoms of copper. So, copper's molar mass is equal to 63.546 g.

In other words, #6.022 * 10^(23)# atoms of copper have a mass of 63.456 g. In order to get the mass of an individual copper atom, divide this mass by how many copepr atoms are in 1 mole.

#1cancel("copper atom") * "63.456 g"/(6.022 * 10^(23)cancel("copper atoms")) = color(green)(1.08 * 10^(-22)"g")#

In order to get how many copper atoms are in one gram of copper, you can write

#1cancel("g copper") * (6.022 * 10^(23)"atoms of copper")/(63.546cancel("g")) = color(green)(9.47 * 10^(21)"atoms")#