Answer:
Step-by-step explanation:
Given data:
Compound saltpeter contains the elements: Potassium (K), Nitrogen (N) and Oxygen (O)
Total Mass of saltpeter = 100 g
Mass of K = 38.67 g
Mass of N = 13.86 g
Mass of O = Total mass - (mass of K + mass of N)
= 100-(38.67 + 13.86) = 47.47 g
Thus, a 100 g sample of saltpeter contains 47.47 g of oxygen
Therefore, a sample of mass 334.0 mg i.e. 0.3340 g would contain:
0.3340 * 47.47/100 = 0.1585 g i.e. 158.5 mg of oxygen