Question

calculate the number of calcium atom in a piece weighing 2.5gram

Answer 1

$=0.0625 mol\\số nguyên tử= 6.22*10^23*0.0625=3.8875*10^22$n=2.5/40

Answer 2

in 40 gm of calcium there are 6.022*10^23 atoms
in 1 gm of calcium there are (6.022*10^23)/40 atoms
in 2.5 gm there are[ (6.022*10^23)/ 40]*2.5 = 6.022*10^23/16
376.375* 10^20
3.76375 * 10^22