1 / 8

Exploring Empirical and Molecular Formulas in AP Chemistry

Learn the concepts of empirical and molecular formulas in chemistry, understand their significance, and solve practice problems to strengthen your understanding.

sasha
Download Presentation

Exploring Empirical and Molecular Formulas in AP Chemistry

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. Chapter 2 Part 2 AP Chemistry 2012

  2. Empirical And Molecular Formulas • What do the following molecular formulas have in common? C6H12, C3H6, C2H4, CH2 • Each of the above molecules have a carbon to hydrogen ratio of 1 to 2. (Or they contain twice as many hydrogen atoms as carbon atoms)

  3. Empirical Formulas • An empirical formula contains the lowest whole number ratio of atoms. • In the previous example, this would be CH2 • Other empirical formulas: H2O C4H8O NO3 CH4

  4. Molecular Formulas • Molecular formulas represent the actual molecule and are based on molar mass. • The molecular formula of the molecule below is C4H10, what is its empirical formula?

  5. Note • A molecular formula can also be an empirical formula.

  6. Determining Molecular Formulas • Question: What is the molecular formula of a compound with the empirical formula C2H6O and a molar mass of 138 g/mol? Solution: 1. Find the molar mass of the empirical formula 2. Divide the molar mass of m.f. by e.f. 3. Multiply the subscripts on the e.f. by the answer you obtained in #2 (2×12g/mol) + (6×1g/mol) + (1×16g/mol) = 46 g/mol 138 g/mol ÷ 46 g/mol = 3 C2 × 3H6 × 3O1 × 3

  7. Book Practice Problems page 71: 2.8, 2.44, 2.50, 2.54, 2.56, 2.66

  8. How does a calcium ion form from a calcium atom?  How many protons, neutrons, and electrons do a calcium atom and ion have?  How does the formation of a cation from a neutral atom differ from the formation of an anion from a neutral atom? • Why don’t we write the formula of the ionic compound formed between Ba2+ and S2- as Ba2S2?  Why is CrO named chromium (II) oxide while CaO is calcium oxide?

More Related