140 likes | 467 Views
The Hamburger. My recipe for a bacon double cheeseburger is: 1 hamburger bun 2 hamburger patties 2 slices of cheese 4 strips of bacon Based on this recipe: If I have five bacon double cheeseburgers: How many hamburger buns do I have? How many hamburger patties do I have?
E N D
The Hamburger • My recipe for a bacon double cheeseburger is: • 1 hamburger bun • 2 hamburger patties • 2 slices of cheese • 4 strips of bacon • Based on this recipe: • If I have five bacon double cheeseburgers: • How many hamburger buns do I have? • How many hamburger patties do I have? • How many slices of cheese do I have? • How many strips of bacon do I have?
Stoichiometry, Ch 9 Chemistry I-A 4-6 days This unit will require you to have more direct instruction from your Teacher. Please use your class time wisely!
Essential Questions for Ch. 9 (Don’t copy or turn in. This is a great test review!) • What do the coefficients of a balanced equation represent? • How do you work basic stoichiometry problems? • How do you convert grams to grams or mixed units using the ratio of coefficients? • What are actual yield, theoretical yield and percent yield? • How can you determine the percent yield of salt (NaCl) in the reaction of sodium hydrogen carbonate and hydrochloric acid? • What are limiting reactants and how are they related to equations and daily applications?
Stoichiometry-STOY-KEE-AHM-EH-TREE • A mathematical process that uses the balanced chemical reaction • Stoichiometry is the measuring and calculating of the amounts of elements and compounds involved in a chemical change. http://www.chem4kids.com/files/react_stoichio.html
The Key to Stoi-key-ometry is in the Coefficients • To calculate the amounts, we use the COEFFICIENTS of the chemical equation. • The coefficients in a balanced reaction represent the ratio of MOLES, LITERS and MOLECULES. • It does NOT REPRESENT the ratio of grams.
The Steps • Balance the equation. • Write down the given and what is wanted and label this information on the equation • Convert to moles if needed (not necessary if you are going from mole to mole, liter to liter or molecule to molecule)
Steps, cont 4. Multiply by the ratio of: • coefficient of want/coefficient of given 5. Convert to the unit that is wanted in the problem
To be successful • You must have a balanced equation • You must show your work. That includes units and names of compounds • No work, no credit, no kidding!
Examples-See your teacher! • Mole to Mole • Molecule to Molecule • Liter to Liter • Mass to Mass • Mixed Units
Percent Yield-measures efficiency • THEORETICAL YIELD – How much product should be produced (calculated from stoichiometry problem) • ACTUAL YIELD - How much product was actually produced in the lab (what you actually produced) • Formula
Example #3__Mg + _CrCl3___MgCl2 + ___Cr • In a lab 50.0g of Mg reacted with CrCl3 to produce MgCl2. If 125.0 g was produced in lab, what was the percent yield of MgCl2? • Theoretical yield – • Actual yield – • % yield = actual/theoretical x 100
Limiting Reactants • A limiting reactant is the starting compound or element that controls how much product is made. It is the one that runs out first.
Resources/Tutorials • http://gemini.tntech.edu/~snorthrup/chem111/tutorials/chap3b/start.html • http://chemistry2.csudh.edu/newlechelp/genstoichiometrycs.html