Answer:
18 * 10^19 atoms
Step-by-step explanation:
We must first convert 57.8 mg to grams.
If 1000 mg = 1g
57.8 mg = 57.8/1000 = 57.8 * 10^-3 g
Now;
If 1 gold atom has a mass of 3.27X10^-22 grams
x gold atoms have a mass of 57.8 * 10^-3 g
x = 57.8 * 10^-3 g/3.27X10^-22 g
x = 18 * 10^19 atoms