A 0.400 gram sample of white powder contains 0.141 of potassium, 0.115 grams of sulfur, and 0.144 grams of oxygen. what is the empirical formula?
i need them
K2S2O5
To determine the empirical formula, we need to find the ratio of atoms in the compound.
First, let's calculate the number of moles for each element using their respective masses:
Mass of potassium (K) = 0.141 grams
Molar mass of potassium (K) = 39.10 g/mol (you can find this on the periodic table)
Number of moles of potassium (K) = Mass of potassium (K) / Molar mass of potassium (K)
= 0.141 g / 39.10 g/mol
= 0.00361 mol
Similarly, we calculate the number of moles for sulfur (S) and oxygen (O):
Mass of sulfur (S) = 0.115 grams
Molar mass of sulfur (S) = 32.07 g/mol
Number of moles of sulfur (S) = 0.115 g / 32.07 g/mol
= 0.00359 mol
Mass of oxygen (O) = 0.144 grams
Molar mass of oxygen (O) = 16.00 g/mol
Number of moles of oxygen (O) = 0.144 g / 16.00 g/mol
= 0.009 mol
Next, we need to find the simplest whole number ratio of the elements in the compound. Divide the number of moles of each element by the smallest value obtained, which in this case is the number of moles of sulfur:
Number of moles of potassium (K) / Number of moles of sulfur (S)
= 0.00361 mol / 0.00359 mol
= 1.003
Number of moles of sulfur (S) / Number of moles of sulfur (S)
= 0.00359 mol / 0.00359 mol
= 1.000
Number of moles of oxygen (O) / Number of moles of sulfur (S)
= 0.009 mol / 0.00359 mol
= 2.51
Round the ratios to the nearest whole number:
K: 1
S: 1
O: 3
Therefore, the empirical formula of the white powder is KSO3.
1. Find the percent of each element.
2. Take a 100 g sample
3. Convert each sample into moles. moles = g/molar mass.
4. Determine the ratio of the elements to each other in whole numbers with the smallest being 1.00. If the numbers don't round to whole numbers, try multiplying each by 1, 2, 3, 4, etc until they can be rounded to whole numbers.