Chemistry I 9.1 – Calculating Quantities in Reactions Objectives and ...

Chemistry I9.1 – Calculating Quantities in ReactionsObjectives and Key Vocabulary· Use proportional reasoning to determine mole ratios from a balanced chemicalequation.· Solve stoichiometry problems involving moles, mass, volume, and the # of particlesusing mole ratios, molar mass, molar volume, and Avogadro‛s number.· stoichiometry______________________________________________________________________________________A. What is stoichiometry?a. Stoichiometry is a branch of chemistry that involves ________________________________________________________________________________________________________________________________________________________B. Balanced Chemical Equations/Rxnsa. Tell us three basic things:i. How many ___________ are involvedii. How many ____________ are involvediii. How many ______________ are involvedEx.: N 2(g) + 3H 2(g) ® 2NH 3(g)· Particles involved? _____________________________· Mass involved? ________________________________· Volumes involved? ______________________________C. Balanced Eqtns Show ProportionsEx.: N 2(g) + 3H 2(g) ® 2NH 3(g)a. Equation tells you for every _____ mole of N 2 and ____ moles of H 2 , _____moles of NH 3 will be produced.b. EQUATIONS ALWAYS NEED TO BE ________________!c. Can make conversion factors from this:

D. Mole-Mole Calculationsa. Given the # of moles of reactant(s), calculate the number of moles ofproduct(s):Ex.: N 2(g) + 3H 2(g) ® 2NH 3(g)i. How many moles of ammonia are produced when 3.2 mol of hydrogenreact with nitrogen?b. Given the # of moles of product(s), find the number of moles of reactants(s):Ex.: N 2(g) + 3H 2(g) ® 2NH 3(g)i. How many moles of nitrogen are needed to make 7.24 moles of NH 3 ?E. Mass-Mass Calculationsa. Given the of a reactant or product, calculate the mass of any other reactant orproduct in the equationi. Use dimensional analysis and go “through” moles. (Go from _______ to_______ to __________.)ii. You‛ll need ____________________!Ex.: N 2(g) + 3H 2(g) ® 2NH 3(g)iii. Calculate the number of grams of NH 3 produced by the reaction of 2.8 gof hydrogen with an excess of nitrogen.

Ex.: N 2(g) + 3H 2(g) ® 2NH 3(g)iv. Calculate the number of grams of N 2 needed to produce 10.0 grams ofNH 3 .F. Other Stoichiometric Calculationsa. Can do calculations between any unit of measurement that is related to themole:i.ii.iii.iv.v.vi. Volume-volume is exception – don‛t need to go through mole!G. Volume-Volume Calculationsa. To calculate volume-volume problems, you don‛t need to go through moles,because molar volume is “mole”.b. Need to remember (or learn) that there are ALWAYS ________ of ONEMOLE of ANY gas at _______ (standard temperature and pressure). Hence,the conversion:c. This can be used in other stoichiometry problems involving volume.

d. What volume of hydrogen is necessary to react with 5.0 liters of nitrogen toproduce ammonia? (Assume STP.)Ex.: N 2(g) + 3H 2(g) ® 2NH 3(g)e. If 15.9 L of C 2 H 2 react at STP, how many moles of CO2 are produced?2C2H 2(g) + 5O 2(g) ® 4CO 2(g) + 2H 2 O (g)f. How many mL of CO 2 can be made when 59.3 mL of O 2 react? (Use above eqtn)H. Many problems, just ONE solution!a. You may think that you have to try to memorize a bunch of different steps andtypes of stoichiometry problems, but that is not the case.i. Figure your __________ point and ______ point.ii. Take whatever you are given, and convert it into _________.iii. Use mole ratio from __________ equation to convert into whatevercompound you need.iv. Finally, find a way to convert those moles into the units that you needfor your final answer!v. This works for _______ stoichiometry problem!