The dimensional analysis is already done, right here, but I'll restate it in nicer format. ##\frac{[g]}{[g/mol]}=[g]\frac{1}{[g/mol]}=[g][mol/g]=[mol]##. Note that dividing by a fraction is simply multiplication by it's reciprocal.Grace Otto said:So my chemistry teacher said that: Moles of a compound = mass of the sample (grams) ÷ molar mass of the compound (grams/mol)
Molar mass is the mass of one mole of a substance, which is equal to its atomic or molecular weight in grams. It is important because it allows us to convert between the mass of a substance and the number of moles, which is crucial for performing calculations in chemistry.
To calculate molar mass, you need to find the atomic or molecular weight of each element in the compound and then multiply it by the number of atoms or molecules present. Then, add all of these values together to get the molar mass of the compound.
Sure, let's take water (H2O) as an example. The atomic weight of hydrogen is 1.01 g/mol, and oxygen is 16.00 g/mol. Since there are two hydrogen atoms and one oxygen atom in water, the molar mass would be (2 x 1.01) + 16.00 = 18.02 g/mol.
In stoichiometry, we use molar mass to convert between the mass of a substance and the number of moles. This allows us to determine the amount of reactants needed to produce a certain amount of product, or the amount of product that can be produced from a given amount of reactants.
One common mistake is forgetting to convert units, as molar mass is typically given in grams per mole. It's also important to use the correct molar mass for each element, as some elements may have different isotopes with varying atomic weights. Additionally, make sure to use the correct number of atoms or molecules when calculating molar mass for a compound.