1 mole of a pure substance has a mass equal to its molecular mass expressed in grams.
This leads to the formula: mass = moles x molar mass, where m = mass of substance in grams, n = moles of pure substance, and M = molar mass of the pure substance in g/mol.
We can write this as m = n x M
We can rearranged this as
n = m / M (moles = mass / molar mass)
M = m / n (molar mass = mass / moles)
In the problem, we have to find the number of moles (n) from the given mass of 2.3 g of phosphorus.
We will use the formula
n = m / M, since we are looking for number of moles
According to the periodic table, the molar mass of phosphorus is 30.97 g/mol
n = 2.3 g / 30.97g/mol
n = 0.074 mol of phosphorus
Answer: 0.074 mol of phosphorus
