Calculating Amounts of Reactants and Products Solid lithium hydroxide is used in space vehicles to remove the carbon dioxide gas exhaled by astronauts. The hydroxide reacts with the carbon dioxide to form solid lithium carbonate and liquid water. How many grams of carbon dioxide can be absorbed by 1.00 g of lithium hydroxide? Propane, C3H8 (Figure), is a common fuel used for cooking and home heating. What mass of O2 is consumed in the combustion of 1.00 g of propane? (a) 5.00 g (b) 0.726 g (c) 2.18 g (d) 3.63 g. Does this reaction produce or consume thermal energy (heat)? ? Figure Propane burning in air. Liquid propane in the tank, C3H8, vaporizes and mixes with air as it escapes through the nozzle. The combustion reaction of C3H8 and O2 produces a blue flame.
Solution 1PE Step 1 1 Balance the equation for the reaction. 2 Convert the known mass of the reactant or product to moles of that substance. 3 Use the balanced equation to set up the appropriate mole ratios. 4 Use the appropriate mole ratios to calculate the number of moles of the desired reactant or product. 5 Convert from moles back to grams if required by the problem The LiOH can absorb 919.9 g of carbon dioxide. Step 2 Explanation: The balanced equation is 2LiOH+CO2Li2CO3+H2O You must make the following conversions: mass of LiOHmoles of LiOHmoles of CO2mass of CO2 1.00×103g LiOH×1 mol LiOH/23.95g LiOH=41.8 mol LiOH 41.8mol LiOH×1 mol CO2/2 mol LiOH=20.9 mol CO2 20.9mol CO2×44.01 g CO2/1mol CO2= 919 g CO2. Step 3 Propane, C3H8 (Figure), is a common fuel used for cooking and home heating. The combustion reaction of propane is represented by the following balanced chemical equation. Here propane one mole reacts with 5 moles of oxygen to give 3 moles of carbon dioxide and 4 molecules of water . We have to calculate the number of moles of propane in 1.00g as follows: C3H8(g)+5O2(g)3CO2+4H2O. Number of moles of propane =weight of propane /molecular mass of propane . =1.00 g/44.0g. =1/44.