Stoichiometry

__**Directions:**__ a) list and define all vocabulary from the chapter b) type at least 4 sample problems with step-by-step directions of how to solve the problem; list the correct answers (if your chapter doesn't have math, there are still problems and concepts we learned.) c) link at least 3 websites for additional resources to help with studying d) develop your own LEQ questions for the section - what did you think were the key points we learned? e) Once your page is done, visit 4 other chapters and answer their LEQ's. (This can be done on a separate piece of paper.)

Definitions: Conservation of Mass: The total mass remains constant when comparing reactants and products (the two will be equal) the total mass of hydrogen and iodine will equal the mass of hydrogen iodide Writing Mole Ratios: this uses the coefficients of a balanced equation to show the relationship between compounds Steps to Stoichiometry: 1) Balance the equation 2) Start with the given number 3) Convert to moles 4) Use mole:mole ratio from balanced equation 5) convert to the required unit using one of the conversion factors Limiting Reagents: determines how much product can be formed Excess: same left over during reaction process How to do the Problem: 1) Convert the grams of each reactant into moles of the product 2) The smaller mole value tells you which starting reactant is the limiting reactant 3) Use the moles of the limiting reagent to calculate the amount of product produced Excess Leftover: 1) Select one product that you formed 2) Convert that product into grams of excess reactant 3) Subtract those grams from the starting grams = how much is left

Sample Problems: If you have 34.1 grams of CuSO4, how many oles of CuSO4 do yo have? How many molecules do you have? Answer: .216 mol; 1.29 x 10-23 molecules If you have 3.21 g of N2, how many g of NH3 will be produced? Answer: 3.90 g NH3 What is the limiting reagent when 80.0 g Cu reacts with 25.0 g S? Answer: 0.629 mol Cu2S is limiting reagent

LEQ: How can we do stoichiometry? How can we determine the limiting reagent?

Helpful Websites: http://www.eepe.murdoch.edu.au/info/student/chemtutorials/stoichiometry/stoich1.html http://chemistry.boisestate.edu/people/richardbanks/inorganic/stoichiometry/stoichiometry.htm http://www.chm.davidson.edu/vce/stoichiometry/ch.html