STOICHIOMETRY HOW TO CALCULATE THE RESULTS OF FRUIT DRINK FERMENTATION

Summary

In this video, Bu Eli explains the stoichiometry calculations involved in anaerobic fermentation using pineapple juice. The video covers key topics like determining the ethanol concentration in a 1.5L pineapple fermentation drink, calculating the volume of CO2 produced, and comparing experimental ethanol yield with reference values. Additionally, it discusses the energy released during the fermentation process, quantifying the heat generated per mole of ethanol. By guiding through the step-by-step calculations and concepts, Bu Eli aims to deepen understanding of fermentation stoichiometry and its practical applications in chemistry.

Takeaways

• 😀 The video explains stoichiometric calculations for ethanol and CO2 production during the anaerobic fermentation of pineapple.
• 😀 The initial calculation involves determining the volume of ethanol in 1.5 liters of fermented pineapple drink, based on its 10% ethanol concentration.
• 😀 The ethanol volume is calculated using the density of the solution (0.97 g/cm³) to find the mass of ethanol in the solution.
• 😀 The mass of ethanol (145.5 g) is converted into moles (0.1630 mol) by using the molar mass of ethanol (46.07 g/mol).
• 😀 Molarity of ethanol in the 1.5 liters of pineapple drink is calculated as 2.11 M (moles per liter).
• 😀 The video explains how to calculate the volume of CO2 gas produced during fermentation using stoichiometric ratios from the balanced reaction equation.
• 😀 Based on the reaction, 3.1630 moles of ethanol yields the same amount of moles of CO2, which is then multiplied by the molar volume of gas (24 L/mol for RTP) to find the gas volume (75 L).
• 😀 The video emphasizes that although the calculated CO2 volume might seem large (75 L), it’s based on theoretical stoichiometry and reaction conditions.
• 😀 The yield efficiency (rendemen) of ethanol is calculated by comparing the experimental ethanol concentration (10%) to the reference value (11%) and multiplying by 100%, resulting in 90.91% efficiency.
• 😀 The energy (caloric) released during fermentation is determined, showing that 2 moles of ethanol produce 210 kJ of heat, and 1 mole releases 105 kJ of energy in an exothermic reaction.
• 😀 The video reinforces the understanding of basic stoichiometry and fermentation concepts, helping to visualize how ethanol and CO2 are produced in pineapple fermentation.

Q & A

What is the main topic discussed in the video?

The main topic of the video is stoichiometric calculations in anaerobic fermentation, specifically focusing on the fermentation of pineapple to produce ethanol.

What is the percentage of ethanol in the pineapple fermentation drink?

The pineapple fermentation drink contains 10% ethanol by volume (V/V).

How is the volume of ethanol in 1.5 liters of the fermented pineapple drink calculated?

The volume of ethanol in 1.5 liters of the drink is calculated by multiplying 1.5 liters by the percentage of ethanol (10%). This results in 150 milliliters of ethanol in the 1500 milliliters of drink.

What is the significance of the density value of 0.97 g/cm³ in this context?

The density of 0.97 g/cm³ is used to calculate the mass of ethanol in the solution, helping to convert the volume of ethanol into grams. This value is crucial for further stoichiometric calculations.

How is the molar mass of ethanol used in the calculations?

The molar mass of ethanol (46.07 g/mol) is used to convert the mass of ethanol (145.5 grams) into moles. This allows the calculation of the molar concentration of ethanol in the solution.

What is the molarity of ethanol in the 1.5 liters of pineapple fermentation drink?

The molarity of ethanol is calculated by dividing the moles of ethanol (0.1630 mol) by the volume of the solution in liters (1.5 L). This gives a molarity of 0.109 mol/L.

How is the volume of CO2 gas produced during fermentation determined?

The volume of CO2 produced is based on the stoichiometry of the fermentation reaction. Given that 1 mole of ethanol produces 1 mole of CO2, the moles of CO2 produced are the same as the moles of ethanol. The volume is then calculated using the molar volume of gas at RTP (24 L/mol).

What is the expected volume of CO2 gas produced in the fermentation process?

The expected volume of CO2 gas produced is calculated as 3.1630 mol of CO2 multiplied by 24 L/mol (at RTP), which gives a total volume of 75.91 liters.

How is the ethanol yield or rendement calculated in this case?

The ethanol yield is calculated by dividing the experimental ethanol concentration (10%) by the reference value (11%) and then multiplying by 100%. This gives a rendement of 90.91%.

What is the amount of energy released during the fermentation reaction?

The amount of energy released is based on the reaction's stoichiometry. For every 2 moles of ethanol produced, 210 kJ of energy is released. Therefore, for 1 mole of ethanol, 105 kJ is released.