Why does topsoil have a dark color)

Calculate the number of molecules present in 0.750 mol of mgo.

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

Find the number of grams of hcl needed to react completely with .50 moles of magnesium.