1 / 9

Empirical & Molecular Formulas for Covalent Compounds

Empirical & Molecular Formulas for Covalent Compounds. empirical formula: Lowest whole number ratio of atoms (EF) molecular formula: Shows the actual number of atoms (MF). Reduced formula. Compound MF EF water H 2 O H 2 O hydrogen H 2 O 2 HO peroxide

adanne
Download Presentation

Empirical & Molecular Formulas for Covalent Compounds

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Empirical & Molecular Formulas for Covalent Compounds • empirical formula: Lowest whole number ratio of atoms (EF) • molecular formula: Shows the actual number of atoms (MF) Reduced formula

  2. Compound MF EF water H2O H2O hydrogen H2O2 HO peroxide sodium Na3N Na3N nitride dinitrogen N2S4 NS2 tetrasulfide

  3. Calculate EMPIRICAL FORMULA from percent composition: 1. Convert percent to grams (assume 100 gram sample) 2. Convert grams to moles (mmpt & factor label) 3. Change moles to whole numbers (divide by smallest) 4. Use moles (whole #’s) as subscripts

  4. If a compound has the following percent composition: 40.0% carbon, 6.71% hydrogen, and 53.3% oxygenDetermine its empirical formulas

  5. Empirical Formula • Convert the percentage to grams and then mols • 40.0% C= 40.0 grams C = 3.33 mols • 6.71% H = 6.71 grams H = 6.71 mols • 53.3% O = 53.3 grams O = 3.33 mols

  6. Empirical Formula • Determine the smallest number of mols and divide into each element to get a whole number. • Smallest no. of mols is 3.33 • Carbon 3.33/3.33 = 1 • Hydrogen 6.71/3.33 = 2 • Oxygen 3.33/3.33 =1 • Use the whole numbers as subscripts • CH2O

  7. Calculate MOLECULAR FORMULAS 1. Calculate the molar mass for the EF 2.Dividemolar mass MF= whole # molar mass EF 3. Multiply whole # times the EF subscripts

  8. If a compound has the following percent composition: 40.0% carbon, 6.71% hydrogen, and 53.3% oxygen and its molar mass is 180 g/molCalculate its empirical and molecular formulas?

  9. Calculate MOLECULAR FORMULAS • Calculate the molar mass for the EF • CH2O-from the previous problem. 12 + 2 + 16 =30 g/mol • Dividemolar mass MF= Whole # molar mass EF • 180 / 30 = 5 • 3. Multiply Whole # times the EF subscripts • C5H10O5

More Related