A pure copper penny contains approximately 3.0 \times 10^{22} copper atoms. I keep forgetting how to convert atoms to moles. ANy help is greatly appreciated!
Copper atoms= 3* 10^22 atoms Number of moles= Number of atoms/ Na... .........Where Na is Avogadro's constant Number of Moles= 3*10^22/ 6.022*10^23 = 0.0498 moles
went to us mint to get stats on how much Cu in in a penny and the weight. 2.5% Cu in a penny, weight 2.5g that means there is 0.0625g in a penny (2.5 x 0.025) GMW of Cu is 58.93 so there is 0.0011 mole in one penny Mulitply that by 6.023 x10^23 to get number of atoms in one penny working backward, if you know the number of atoms in a sample 6.023x 10^23/ 3.0x 10^22 = 58.93/x x (6.023 x10^23) = (58.93) (3.0 x 10^22) solve for x
(2.44g Cu X 6.022x10^23 atoms Cu)/sixty 3.fifty 5 Cu = 2.31 x 10^22 atoms Cu (Mass of copper X # of moles X # of atoms in one mole, all divided by way of molar mass of copper X # of moles)
