36 which compound has the highest percent com­position by mass of strontium?
(1) src12 (2) sri2 (3) sro (4) srs

To solve this problem we must first find the masses of each individual compound. Then we can use the following equation:
(mass of strontium) / (mass of compound) * 100% = (percent mass of Strontium)

1. The mass of strontium is 87.62 and the mass of Chlorine is 35.45. There are 2 chlorine atoms in the compound, so 35.45*2 = 70.9. Add the strontium to get the mass of compound. 70.9 + 87.62 = 158.52. Now, we can use the equation. 

87.62 / 158.52 * 100% = 55.27% Strontium

2. There are 2 Iodine atoms in the compound, and the molar mass of Iodine is 126.9. The mass of the compound is 126.9 + 87.62 = 214.52. Now, we can use the  equation

87.62 / 214.52 * 100% = 40.84% Strontium

3. The molar mass of Oxygen is 16, and there is only one oxygen atom. So the mass of the compound will be 16 + 87.62 = 103.62. Now we can use the equation.

87.62 / 103.62 * 100% = 85.46% Strontium

4. Finally, the molar mass of sulfur is 32.06, and there is only one sulfur atom in the compound, so the mass will be 32.06 + 87.62 = 119.68. Now we can use the equation

87.62 / 119.68 * 100% = 73.21% Strontium

Therefore, the answer is 3 because it has the highest percentage of Strontium than the other compounds. Hope this helped!! :D