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Stoichiometry II - Mole Calculations/ Limiting and Excess Reagent – Lecture Notes 1. Given the balanced equation N2(g) + 3H2(g) 2NH3(g) How many moles of ammonia are produced when 0.60 mol of nitrogen reacts with hydrogen? 2. Given the equation: SiO2 + HF SiF4 + H2O a. Calculate the number of moles HF that would completely react with 2.5 moles of SiO2. b. Calculate the number of moles SiF4 formed by completely reacting 2.5 moles SiO 2 with HF. c. Calculate the mass of water formed by reacting 2.5 moles SiO 2 with HF.
d. Calculate the number of water molecules formed by reacting 2.5 moles SiO 2 with HF.
e. Calculate the mass of oxygen formed by reacting 2.5 moles SiO 2 with HF. 3. Calculate the number of grams NH3 produced by the reaction of 5.40 grams of hydrogen with an excess nitrogen.
1. The overall reaction for the conversion of sugar(glucose) to acetic acid is: C6H12O6 + 2O2 2CH3COOH + 2CO2 + 2H2O
A given volume of nipa sap contains 69.0 g of glucose. If all of this sugar is fermented , how many grams of acetic acid would be produced?
2. How many molecules of oxygen are produced when 29.2 g of water is decomposed forming hydrogen gas and oxygen gas?
3. Hydrofluoric acid, HF(aq), cannot be stored in glass bottles because compounds called silicates in the glass are attacked by the HF(aq). Sodium silicate(Na2SiO3), for example reacts as follows:
Na2SiO3(s) + 8 HF(aq) H2SiF6(aq)
a. How many moles of HF are needed to react with 0.300 mol Na2SiO3?
b. How many grams of NaF form when 0.500 mol of HF reacts with excess sodium silicate?
How many grams sodium silicate can react with 0.800 g of HF?
4. Automotive air bags inflate when sodium azide, NaN3, rapidly decomposes to its component elements: 2 NaN3(s) 2Na(s) + 3N2 (g) a. How many moles of N2 are produced by the decomposition of 2.50 mol NaN3? b. How many grams of NaN3 are required to form 6.00 g of nitrogen gas?
5. The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: 2C8H18(l) + 25 O2 (g) 16 CO2(g) + 18 H2O(g) a. How many moles of O2 are needed to burn 0.750 mol of C8H18? b. How many grams of O2 are needed to burn 5.00 g of C8H18 ?
6. Detonation of nitroglycerin proceeds as follows: 4C3H5N3O9 (l) 12 CO2(g) + 6N2(g) + O2(g) + 10H2O (g)
a) If a sample containing 3.00 mL of nitroglycerin ( d = 1.592 g/ml) is detonated, how many total moles of gas are produced?
b) How many grams of N2 are produced in the detonation? Limiting Reagents and Excess Reagents 1. Sodium chloride can be prepared by the reaction of sodium metal with chlorine gas. 2Na(s) + Cl2(g) 2NaCl(s)
a. If 6.70 mol Na reacts with 3.20 mol Cl2 what it the limiting reagent? b. How many moles of NaCl are produced?
How much of the excess reagent remains unreacted?
2. Phosphorus trichloride, PCl3 is commercially important compound used in the manufacture of pesticides, gasolines, additives, and number of other products. It is made by the direct combination of phosphorus and chlorine. P4 + 6Cl2 4PCl3 What mass of PCl3 forms in the reaction of 125 g P4 with 323 g Cl2?
3. Sodium hydroxide reacts with carbon dioxide as follows; 2NaOH(s) + CO2 (g) Na2CO3 (s) + H2O (l)
a. Which reagent is a limiting reactant when 1.70 mol NaOH and 1.00 mol CO 2 are allowed to react?
b. How many moles of Na2CO3 can be produced?
How many moles of the excess reactant remain after the completion of the reaction?
1. The fizz produced when Alka-Seltzer tablet is dissolved in water is due to the reaction between sodium bicarbonate (NaHCO3) and citric acid ( H3C6H5O7) : 3NaHCO3 (aq) + H3C6H5O7 (aq) 3CO2(g) + 3H2O(l) + Na3C6H5O7(aq) In a certain experiment 1.00 g of sodium bicarbonate and 1.00 g of citric acid are allowed to...