Answer:
2:3
Step-by-step explanation:
To determine the empirical formula of the compound, we need to convert the given masses of neodymium and sulfur to moles, and then find the simplest whole number ratio of the moles of each element in the compound.
The atomic mass of neodymium is 144.24 g/mol, so the number of moles of neodymium is:
17.20 g Nd × (1 mol Nd/144.24 g Nd) = 0.1193 mol Nd
The atomic mass of sulfur is 32.06 g/mol, so the number of moles of sulfur is:
2.55 g S × (1 mol S/32.06 g S) = 0.0796 mol S
To find the empirical formula, we divide each of the mole amounts by the smallest one (0.0796 mol S in this case) to get the simplest whole number ratio:
0.1193 mol Nd ÷ 0.0796 mol S = 1.50
0.0796 mol S ÷ 0.0796 mol S = 1.00
Rounding to the nearest whole number, we get a ratio of 2:3, so the empirical formula of the compound is Nd2S3.
ALLEN