arnaldo-cruz
Uploaded by
19 SLIDES
325 VUES
190LIKES

Stoichiometry

DESCRIPTION

Stoichiometry is the study of mass relationships in chemical reactions, focusing on mole conversions and the relationships between reactants and products. Core concepts include balanced equations and molar ratios, which allow for mole-mole, mass-mole, mole-mass, and mass-mass problem-solving. This chapter covers limiting reactants, where the amount of product is determined by the reactant that limits reaction capacity. Additionally, we discuss percent yield, comparing theoretical yields to actual lab outcomes.

1 / 19

Télécharger la présentation

Stoichiometry

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. Stoichiometry Chapter 9

  2. Stoichiometry • Def: study of mass relationships in chemical reactions • Mole conversions • Relationship between products and reactants

  3. Stoichiometry • Revolve around balanced equations: • Coefficients = # particles # of MOLES of particles 2H2 + O2 2H2O 2 moles H2 + 1 mole O2  2 moles H2O

  4. Stoichiometry • MOLAR RATIOS!! • 2H2 + O2 2H2O • Molar ratio of: • H2 : O2? • H2 : H2O • O2 : H2O • Use these as conversion factors!

  5. Mole-Mole Problems • 2H2 + O2 2H2O • How many moles of H2 are required to react with 2.5 mole O2? • How many moles of Al(NO3)3 are produced when .75 mol AgNO3 reacts with Al?

  6. Mass-Mole Problems • Fe2O3 + Al  Al2O3 + Fe • How many moles of Fe are produced when 5.50 g of Fe2O3 reacts? • How many moles of water are required to react with .25 g of Na?

  7. Mole-Mass Problems • Mg + O2 MgO • How many grams of MgO can be produced from 2.95 mol Mg reacting with oxygen? • F2 + KBr  KF + Br2 • What mass of KBr is needed to react with 0.96 mol F2?

  8. Mass-Mass Problems • Sodium phosphate reacts with magnesium nitrate • If you have 3.12g of magnesium nitrate, how many grams of magnesium phosphate will you produce?

  9. Helpful Sites • Mole - Mole • http://science.widener.edu/svb/tutorial/rxnsmolestomolescsn7.html • Mass - Mass • http://science.widener.edu/svb/tutorial/rxnsgramstogramscsn7.html

  10. Limiting Reactants

  11. Limiting Reactants • Amount of products depends on amount of reactants • Car runs because gas reacts with O2 • Out of gas = car doesn’t run • Gas = limiting reactant

  12. Limiting Reactants • Limiting reactant – reactant that limits the amount of product • Amount of product will ONLY be amount made from limiting reactant • Excess reactant– reactant that is not used up completely

  13. Finding the Limiting Reactant • Balance the equation • Pick 1 product and calculate the amount of product produced from both reactants • Reactant that produced the smallest amount of product is limiting reactant

  14. More about Limiting Reactants • Fe + S  FeS • 650. g Fe reacts with 650. g S, what is the LR? • What is the mass of sulfur in excess? • http://www.chemcollective.org/applets/stoich.php

  15. Finding the Limiting Reactant • Cu + AgNO3 Cu(NO3)2 + Ag • If 3.1 mol Cu and 3.1 mol AgNO3 react, what is the limiting reactant? • How many grams of Ag will be produced? • Mass excess reactant unreacted?

  16. Percent Yield • Amount you calculate isn’t what you always produce • Lab errors • Theoretical Yield – amount produced based on calculations

  17. Percent Yield • Actual Yield – amount of product “actually” obtained from lab • Percent Yield – percent of product you actually recovered in lab

  18. Percent Yield • % Yield = actual yield x 100 theoretical yield

  19. Percent Yield • Pb(NO3)2 + KI  PbI2 + KNO3 • Determine the % yield if 16.4 g Pb(NO3)2 reacts with 28.5 g KI if 18.3g PbI2 is produced.

More Related