Lab 9: Empirical Formulas & Molecular Formulas
Date:
Name/Partner
Purpose: To determine the empirical and molecular formulas of various unknown compounds.
Procedure:
1. Determine the number of atoms in a pure sample of one of the elements in the NEW PERIODIC TABLE.
A. Determine the mass of your pure element.
B. Use the table below to determine the Molar Mass of your known element.
C. Calculate the number of atoms within your known elemental sample.
2. Determine the number of molecules of a known compound formed by the elements in the NEW PERIODIC TABLE.
A. Determine the mass of your pure compound.
B. Use the table below to determine the Molar Mass of your known compound.
C. Calculate the number of molecules within your known compound.
3. Determine the Empirical Formula and of an unknown compound from its original
mass and the mass of its individual elements.
A. Determine the mass of the pure compound.
B. Determine the masses of the individual elements that were found to be within your pure compound.
C. Determine the Empirical Formula of your sample.
Washers - 1A
Gw -Goldwash1.32 / Nuts - 2A / Bolts - 3A / Bolts - 4A / Bolts - 5A / Bolts - 6A
Jw - Jordanwash
3.90 / Dn - Dosenut
5.07 / Ab - Autumnbolt
5.07
Sw - Splitwash
6.54 / Rn - Rebanut
6.90 / Kb - Katibolt
8.34 / Jb - Jbolt
12.6
Wb - Wallbolt
21.2
Dw Downeywash
25.9 / Mn - Marcoconut
28.6
An - Allinut
40.9
Tw - Tywash
52.0
Cb - Connobolt
77.0 / Hb - Huenebolt
149.
1 Molly = 6 particles (atoms, molecules, ions, formula units)
Lab 9: follow-up
Conclusions & Questions:
1. Determine the empirical formula from a compound composed of Dw and Cb (NOT Cn). After decomposing this compound, the masses of the parts are found to be 25.0 g of Dw and 147.80 g of Cb.
2. Determine the empirical formula from a compound composed of Dn, Rn, Gw, and Wb. Again, after decomposition of this compound the masses were found to be 7.5g, 15.3g, 1.95g, and 15.9 g respectively.
3. Determine the empirical formula of another compound whose constituent parts have the following masses: Mn = 110.0 g ; Ab = 27.5 g. Try to determine the empirical formula by dividing the larger mass by the smaller mass and the smaller mass by itself. Why are these values WRONG?
Lab 9: follow-up
Conclusions & Questions:
1. Determine the empirical formula from a compound composed of Dw and Cb (NOT Cn). After decomposing this compound, the masses of the parts are found to be 25.0 g of Dw and 147.80 g of Cb.
2. Determine the empirical formula from a compound composed of Dn, Rn, Gw, and Wb. Again, after decomposition of this compound the masses were found to be 7.5g, 15.3g, 1.95g, and 15.9 g respectively.
3. Determine the empirical formula of another compound whose constituent parts have the following masses: Mn = 110.0 g ; Ab = 27.5 g. Try to determine the empirical formula by dividing the larger mass by the smaller mass and the smaller mass by itself. Why are these values WRONG?
Lab 9: follow-up
Conclusions & Questions:
1. Determine the empirical formula from a compound composed of Dw and Cb (NOT Cn). After decomposing this compound, the masses of the parts are found to be 25.0 g of Dw and 147.80 g of Cb.
2. Determine the empirical formula from a compound composed of Dn, Rn, Gw, and Wb. Again, after decomposition of this compound the masses were found to be 7.5g, 15.3g, 1.95g, and 15.9 g respectively.
3. Determine the empirical formula of another compound whose constituent parts have the following masses: Mn = 110.0 g ; Ab = 27.5 g. Try to determine the empirical formula by dividing the larger mass by the smaller mass and the smaller mass by itself. Why are these values WRONG?
Lab 9: follow-up
Conclusions & Questions:
1. Determine the empirical formula from a compound composed of Dw and Cb (NOT Cn). After decomposing this compound, the masses of the parts are found to be 25.0 g of Dw and 147.80 g of Cb.
2. Determine the empirical formula from a compound composed of Dn, Rn, Gw, and Wb. Again, after decomposition of this compound the masses were found to be 7.5g, 15.3g, 1.95g, and 15.9 g respectively.
3. Determine the empirical formula of another compound whose constituent parts have the following masses: Mn = 110.0 g ; Ab = 27.5 g. Try to determine the empirical formula by dividing the larger mass by the smaller mass and the smaller mass by itself. Why are these values WRONG?