Lesson 2: Objectives
Purpose:
To become familiar with the idea of atoms and learn how they are related to elements and compounds.
Objectives:
You have completed this lesson when you can:
1. Define and distinguish between fact, observation, inference, hypothesis, scientific law, theory, and model.
2. Describe the scientific method and list four criteria for judging theories.
3. Describe and distinguish between these categories of materials: mixtures, solutions, pure substances, compounds and elements.
4. Explain what is meant by the Law of Constant Composition, as well as stating it, recognizing it, or identifying examples of it. Use it to distinguish between compounds and other classes of materials.
5. Relate (equate, memorize) the names and symbols for the following elements: Ag, Al, Ar, Au, B, Ba, Be, Br, C, Ca, Cl, Co, Cr, Cu, F, Fe, H, He, Hg, I, K, Li, Mg, Mn, N, Na, Ne, Ni, O, P, Pb, S, Si, Sn, Ti, Zn.
6. Locate these elements on the periodic table and identify the group and period for each.
7. Use the names of compounds to determine what elements are present in them.
8. State and recognize the basic points of Dalton's Atomic Theory. Describe Dalton's model of atoms.
9. Define "relative atomic weight." Give a brief history of atomic weight standards, and cite the reasons for the changes that have been made.
10. Define "mole" (without using or even knowing about Avogadro's number). (If you must use Avogadro's number, explain why that particular number was chosen.)
11. Describe the relationship between the mole and the atomic weight (and also the formula or molecular weight).
12. Convert from grams to moles and from moles to grams.
13. Define "compound" and "molecule" and distinguish between them. Criticize the statement "Elements are made of atoms and compounds are made of molecules."
14. State Avogadro's Law and explain how it relates to molecules and compounds and elements. Describe the differences between Avogadro's "molecule" and Dalton's "compound atom."
15. Express the composition of chemicals using formulas. Given the number of each kind of atom in a compound, write its formula--and vice versa.
16. Define and distinguish between empirical and molecular (and structural) formulas.
17. Define and calculate formula weights (including molecular weights) given the formula of a chemical and the appropriate atomic weights.
18. Determine the percent composition by mass of a compound from its formula and a list of atomic weights.
19. Calculate the percent composition by mass of a compound or solution given the weights of the components.
20. Determine the empirical formula of a compound from its composition or similar data.
21. Experimentally determine the molecular weight of gases.
22. Determine the molecular formula of a compound given its empirical formula and its molecular weight.
23. Write a clear, concise, neat lab report using the specified format.
Assignments:
To be turned in -
- Lab Report on exercise 19 (molecular weights of gases)
- Problem Set
Outside Reading (optional): Find the sections in your text that deal with the following topics and read them.
- Scientific Method
- Elements
- Compounds
- Chemical formulas (empirical and molecular)
- Formula weights
- Composition
- Moles