If salicylic acid costs $21 per kilogram, how much would it cost to purchase enough salicylic acid (formula mass= 138.1) to make 1.0 kilogram of aspirin (formula mass= 180.2), assuming your percent yield was obtained in the reaction? (Note 1 to 1 mole ration in equation).
Hint: This is a two step process. First use the % yield relationship to calculate theoretical amount of aspirin needed to get an actual amount of 1.0 Kg of aspirin. Then use the stoichiometric relation from the chemical equation to calculate how much salicylic acid would be needed to make that much aspirin.
I don't know how to setup!
Bob Pursley told you yesterday in your post of this same question that the hint told it all. So you do the two step tango. Have you used % yield to calculate the theoretical amount of aspirin need to get 1.0 kg?
% yield = [(actual amount/theoretical amount)]*100 = ?
Second step is to use stoichiometry to calculate the amount salicylic acid you need.
Still have no clue what goes where!
C'mon. I assume you have done an experiment that determined the % yield for the reaction. That goes in for % yield in my last response to you. Plug that in. You want 1 kg. That goes in for the amount you want. Solve for the theoretical amount you must start with.
I assume you know how to do stoichiometry for the second part.
To solve this problem, you'll need to break it down into two steps.
Step 1: Calculate the theoretical amount of aspirin needed to obtain 1.0 kilogram of aspirin, taking into account the percent yield.
Step 2: Use the stoichiometric ratio from the chemical equation to calculate how much salicylic acid would be needed to make that amount of aspirin.
Step 1:
First, you need to calculate the theoretical amount of aspirin needed to obtain 1.0 kilogram of aspirin, considering the percent yield. The percent yield represents the efficiency of a chemical reaction and is given as a percentage.
Let's assume the percent yield is given as 80%. To calculate the theoretical amount of aspirin needed, you divide the desired actual amount of aspirin (1.0 kilogram) by the percent yield (80% or 0.8).
The formula for theoretical yield is:
Theoretical yield = Actual yield / Percent yield
Theoretical yield = 1.0 kg / 0.8 = 1.25 kg
So, you would need 1.25 kilograms of aspirin to obtain 1.0 kilogram, accounting for the 80% yield.
Step 2:
Now that you know the theoretical amount of aspirin needed, you can use the stoichiometric relationship from the chemical equation to calculate the amount of salicylic acid required.
The balanced equation for the synthesis of aspirin from salicylic acid is:
C7H6O3 + C4H6O3 --> C9H8O4 + H2O
From the equation, you can see that the stoichiometric ratio between salicylic acid (C7H6O3) and aspirin (C9H8O4) is 1:1.
Therefore, the amount of salicylic acid needed would be the same as the amount of aspirin needed. So, you would need 1.25 kilograms of salicylic acid.
Now, multiply the amount of salicylic acid needed by its cost per kilogram ($21) to find the total cost:
Total cost = Amount needed * Price per kilogram
Total cost = 1.25 kg * $21/kg
Total cost = $26.25
Therefore, it would cost $26.25 to purchase enough salicylic acid to make 1.0 kilogram of aspirin, assuming the percent yield was obtained in the reaction.