copper has a molar mass of 63.55 g/mol. a mole contains 6.02 * 10^23 particles. how many particles are in 20 g of copper?A. 1.895 * 10^23B. 6.022 * 10^23C. 1.913 * 10^24D. 6.355 * 10^24
20 grams of Cu 1 mole Cu 6.02x10^23 particles ---------------------- X ----------------------- X -----------------------= 63.55 grams Cu 1 mole of Cu sorry I don't have a calculator! but I'm POSITIVE that's how you set it up ! I'm currently in Chemistry 2 in High School :) hope my set up makes sense, just multiply the 20 grams & 6.02x10^23 particles, then divide that number by the 63.55 grams Cu
If copper has a molar mass of 63,55g/mol, 20g of copper correspond to how many moles? 1 mole --------------------- 63,55g x ----------------------------- 20g 63,55x = 20 x = 20 / 63,55 x = 0,315 mole As 1 mole contains 6,02.10?? particles, how many particles are in 0,315 mole? 1 mole -------------------- 6,02.10?? particles 0,315 mole ------------------- x x = 0,315 . 6,02.10?? x = 1,896.10?? The alternative that is nearest of the found result is A.
20.0g / 63.55g/mol = 0.315mol 0.315mol x 6.02 x 10?? particles = 1.895 x 10?? particles ∴ The answer is choice A
First get the 20 grams of copper into moles Moles = grams copper over grams copper in one mole Moles = 20 g copper over 63.55 g copper per mole Moles copper = .315 moles copper Since you know that a mole of any substance contains 6.02 x l0^23 particles, all we do now is multiply .315 moles times 6.02 x l0^23 particles per mole to get l.89 x l0^23 particles choice A
