The compound name for H3S5 is hydrosulfide sulfanide sulfide
2.998e^8 is how I would write it. If you want it with the least amount of decimals, use 3e^8
The molecular weight of hemoglobin can be calculated using osmotic pressure
Osmotic pressure is a colligative property and it depends on molarity as
πV = nRT
where
π = osmotic pressure
V = volume = 1mL = 0.001 L
n = moles
R = gas constant = 0.0821 L atm / mol K
T = temperature = 25°C = 25 + 273 K = 298 K
Putting values we will get value of moles

we know that

Therefore

It should be 24 electrons