Percent composition by mass is calculated (mass of element within compound)/(mass of compound)*100. The lower the total molar mass of the compound, the greater the percent composition of sulfur. In this case, MgS would be that compound, since Mg has the lowest molar mass of the four elements bonded to S.
Buffers - mixtures of conjugate acid and conjugate base at ±1 pH unit from pH = pKa. Resistant to changes in pH in response to small additions of H+ or OH-. ... Polyprotic acids - dissociation of each H+ can be treated separately if the pKa values are different
Transform the g into kg by multiplying 0.74 by 10^-3. then divide 2.4 kg by the density
If there is more soil, there would be more plants, and thus, more organisms, depending on if the soil has enough nutrients to support an ecosystem. The way that this would affect the climate is that it would transpire moisture into the atmosphere, and also generate fresher air through photosynthesis.