Stoichiometry Dry Lab Name: Mole-Mass Conversions The molar mass of a substance is the conversion factor that allows us to convert between the mass of a substance (in grams) and the number of moles of that substance that are present. (Remember that one mole contains 6.0 x 10 atoms, ions, molecules or formula units.) To convert from grams to moles Take the mass and divide by the molar mass of the substance. For example: How many moles of H are present in 1.7 g of H? 1molH 1.7gH.016gH = 7.9molH To convert from moles to grams Take the number of moles and multiply by the molar mass of the substance. For example: How many mg of O are present in 0. mol of O?.00gO 0.molO 1molO 1000mg 1g = 7.0 mgo 10 1. Find the mass for each of the following: a..86 moles of B O b. 17 mol of Li CO c..568 mol of I d. 0.5 mole of acetaminophen, C 8 H 9 O N
. Find the number of moles in each of the following: a..75 g of aluminum hydroxide b. 0.7 kg of magnesium nitride c.. g of argon d. 7.85 mg of I e. 0.96 g of iron (III) hydroxide
Mole-Mole Conversions The formula for a compound implies a ratio of the number of atoms in each formula unit or molecule of the compound. These ratios also apply to the number of moles of each atom in a mole of the compound. These ratios can be used to develop conversion factors for solving chemical problems. For example, in the compound Ca, every mole of Ca contains moles of Ca and moles of. From this, the following -element/compound mole-mole conversion factors can be developed: mol Ca mol 1 mol Ca 1 mol Ca 1 mol Ca mol Ca 1 mol Ca mol 1. Write of the 6 possible element/compound mole-mole conversion factors that can be derived from the formula for the compound Li CO.. How many moles of hydrogen atoms are present in 1. mol of (NH ) O?. How many moles of nitrogen atoms are present in 1. mol of (NH ) O?. Determine the mass of oxygen in each of the following compounds: a. 1.7 g of carbon dioxide b. 19.1 kg of lithium carbonate c. 6 g of glucose (C 6 H 1 O 6 )
Stoichiometry Just as the subscripts in the formula of a compound tell us how the quantities of atoms are related within a molecule, the stoichiometric coefficients in a balanced reaction tell us about how the quantities of reactant and product molecules (or formula units) are related to each other. These can also be setup as ratios or equalities to allow us to solve chemical calculations. For example, in the reaction: Al (SO ) + Ba(OH) BaSO + Al(OH) The following 6 mole-mole relationships can be written: 1 mol Al ( SO ) 1 mol Al ( SO ) mol Ba ( OH ) 1 mol Al SO mol BaSO mol Al OH ( ) mol Ba( OH) ( ) mol Ba OH mol BaSO mol Al OH 1. Determine at least possible mole-mole relationships that can be derived from the following equation. NH + O N + H O ( ) mol BaSO ( ) mol Al( OH). Given: KClO (s) O (g) + KCl (s) How many moles of KCl is produced when 1.5 mol KClO is decomposed?. The reaction N (g) + H (g) NH (g) is used to produce NH. How many moles of H (g) are required to produce.50 g of NH (g)?
5. Given: C 5 H 1 (l) + O (g) CO (g) + H O(g) Calculate the grams of O (g) gas needed to react with.00 mol of C 5 H 1. 5. Given: N (g) + O (g) N O 5 (g) How many moles of O (g) are needed to react with 1.50 moles of N (g)? 6. How many moles of Al would be required to produce 18.0 mol of H according to the following unbalanced equation? HCl + Al H + AlCl 7. Consider the reaction: S (s) + H SO (aq) SO (g) + H O (l).80 g of sulfur reacts with excess sulfuric acid, what mass of water will be produced?
6 8. Balance the following equation and answer each question: NH + O N + H O a. How many grams of N can be produced from the reaction of 5.8 mol of NH with excess oxygen? b. How many grams of O would be required to produce 1.5 g of N? c. Find the mass of ammonia needed to produce 19.1 g of water. 9. Reacting gaseous ammonia (NH ) with carbon dioxide produces solid urea (NH ) CO and water. Calculate how many grams of urea would be produced from 55.7 grams of ammonia. NH + CO H O + (NH ) CO