Give the percent yield when 15.9 g of CO2 are formed from the reaction of 4.000 moles of C8H18 with 4.000 moles of O2.
2 C8H18 + 25 O2 -> 16 CO2 + 18 H2O
1. Determine the limiting reagent.
2. Convert the limiting reagent to grams.
3. %yield = (15.9/g limiting reagent)*100 = ??
To calculate the percent yield, you need to know the theoretical yield and the actual yield.
The balanced equation gives you a ratio of 2 moles of C8H18 to 16 moles of CO2. So you can use this ratio to calculate the theoretical yield of CO2.
Step 1: Calculate the moles of C8H18.
Given that you have 4.000 moles of C8H18, you don't need to perform any calculations here.
Step 2: Calculate the moles of CO2.
Using the stoichiometric ratio from the balanced equation, you can determine that for every 2 moles of C8H18, 16 moles of CO2 are produced. Therefore, for 4.000 moles of C8H18, you would expect to produce (4.000 moles C8H18) x (16 moles CO2 / 2 moles C8H18) = 32.000 moles of CO2.
Step 3: Convert moles of CO2 to grams.
The molar mass of CO2 is 44.01 g/mol. Therefore, the theoretical yield of CO2 in grams is (32.000 moles CO2) x (44.01 g CO2 / 1 mole CO2) = 1,408.32 g CO2.
Now, to calculate the percent yield:
Step 4: Calculate the actual yield.
Given that 15.9 g of CO2 are formed, you have the actual yield.
Step 5: Use the formula for percent yield.
Percent yield is calculated using the formula: (actual yield / theoretical yield) x 100%.
Plugging in the values we have:
(actual yield / theoretical yield) x 100% = (15.9 g CO2 / 1,408.32 g CO2) x 100% ≈ 1.13%
Therefore, the percent yield is approximately 1.13%.