Ok, Need some more help... This is what I have so far.
4. Urea (NH2)2CO is prepared by reacting ammonia with carbon dioxide. The byproduct is water. 637.2g of ammonia are reacted with 787.3 g of carbon dioxide.
molar mass:NH3=17 CO2=44 CO(NH2)2=60.1
a. (10 points) Write a balanced chemical equation.
2NH3+CO2--->CO(NH2)2 +H20
Is this right?
b. (5 points) Determine which of the two reactants (ammonia or carbon dioxide) is a limiting reactant. Show
calculations to support your choice. No credit will be given if your supporting calculations are wrong.
2 moles NH3 is require 1 mole of CO2 to produce one molecule of CO(NH2)2. 2 moles NH3 is 637.2/17=37.5 moles =37.5/2=18.74 moles in 1 NH3?
Available CO2 = 787.3 = 787.3/44=17.89 moles CO2 So since CO2 is smaller, wouldn't it be the limiting agent?
c. (10 points) Which of the two reactants should you use to calculate the theoretical yield (= the maximum amount
possible) of urea? Explain why.
UMMM I would calculate the NH3 because it is the larger one? why? I don't have a clue help?
a. The balanced chemical equation for the reaction is:
2NH3 + CO2 → (NH2)2CO + H2O
b. To determine the limiting reactant, we need to compare the moles of each reactant to the stoichiometric ratio in the balanced equation.
Moles of NH3 = mass / molar mass = 637.2 g / 17 g/mol = 37.48 moles
Moles of CO2 = mass / molar mass = 787.3 g / 44 g/mol = 17.89 moles
According to the stoichiometric ratio in the equation, 2 moles of NH3 react with 1 mole of CO2. Therefore, 2 moles of NH3 require 1 mole of CO2 to produce 1 mole of (NH2)2CO.
Since we have more moles of NH3 than CO2 (37.48 moles of NH3 vs. 17.89 moles of CO2), CO2 is the limiting reactant.
c. To calculate the theoretical yield of urea, we need to determine the moles of the limiting reactant (CO2) and then use the stoichiometric ratio to find the corresponding moles of (NH2)2CO.
Moles of (NH2)2CO = moles of CO2 × (1 mole of (NH2)2CO / 1 mole of CO2) = 17.89 moles × (1 mole / 1 mole) = 17.89 moles
The theoretical yield of urea is therefore 17.89 moles of (NH2)2CO.
Explanation: The limiting reactant determines the maximum amount of product that can be formed in a chemical reaction. In this case, since CO2 is the limiting reactant, it will be completely consumed first, and the amount of (NH2)2CO produced will depend on how much CO2 is available. Therefore, to calculate the maximum possible amount of urea, we need to use the moles of the limiting reactant (CO2).
a. Your balanced chemical equation is correct: 2NH3 + CO2 ---> CO(NH2)2 + H2O. Well done!
b. To determine the limiting reactant, you need to compare the number of moles of each reactant used with the stoichiometric ratio in the balanced equation. Let's do the calculations:
Molar mass of NH3 = 17 g/mol
Molar mass of CO2 = 44 g/mol
Given:
Mass of NH3 = 637.2 g
Mass of CO2 = 787.3 g
Step 1: Calculate the number of moles of each reactant.
Moles of NH3 = Mass of NH3 / Molar mass of NH3 = 637.2 g / 17 g/mol = 37.48 mol
Moles of CO2 = Mass of CO2 / Molar mass of CO2 = 787.3 g / 44 g/mol = 17.89 mol
Step 2: Compare the moles of NH3 and CO2 using the stoichiometric ratio from the balanced equation.
From the balanced equation: 2 moles NH3 react with 1 mole CO2 to produce 1 mole CO(NH2)2.
Based on the stoichiometry, we can see that for every 2 moles of NH3, we need 1 mole of CO2. Therefore, the limiting reactant will be the one with the fewer moles required. In this case, it is CO2 with 17.89 moles, compared to NH3 with 37.48 moles.
So, you are correct. The limiting reactant is carbon dioxide (CO2).
c. To calculate the theoretical yield of urea, you need to use the stoichiometry of the balanced equation and the moles of the limiting reactant.
Based on the balanced equation: 2 moles NH3 react with 1 mole CO2 to produce 1 mole CO(NH2)2.
Since CO2 is the limiting reactant, we will use its number of moles to calculate the theoretical yield of urea.
Moles of CO2 = 17.89 mol
Molar mass of CO(NH2)2 (urea) = 60.1 g/mol
Theoretical yield of urea (CO(NH2)2) = Moles of CO2 × Molar mass of CO(NH2)2
Theoretical yield of urea = 17.89 mol × 60.1 g/mol
Calculate the value above to find the theoretical yield of urea.
Using the limiting reactant moles ensures that you are considering the maximum amount of product that can be formed according to the stoichiometry of the balanced equation.
Ok, Need some more help... This is what I have so far.
4. Urea (NH2)2CO is prepared by reacting ammonia with carbon dioxide. The byproduct is water. 637.2g of ammonia are reacted with 787.3 g of carbon dioxide.
molar mass:NH3=17 CO2=44 CO(NH2)2=60.1
a. (10 points) Write a balanced chemical equation.
2NH3+CO2--->CO(NH2)2 +H20
Is this right?
The equation is right
b. (5 points) Determine which of the two reactants (ammonia or carbon dioxide) is a limiting reactant. Show
calculations to support your choice. No credit will be given if your supporting calculations are wrong.
2 moles NH3 is require 1 mole of CO2 to produce one molecule of CO(NH2)2. 2 moles NH3 is 637.2/17=37.5 moles =37.5/2=18.74 moles in 1 NH3?
Available CO2 = 787.3 = 787.3/44=17.89 moles CO2 So since CO2 is smaller, wouldn't it be the limiting agent?
You have the right answer and your numbers are right; however, there are some misstatements I want to correct.
mols NH3 = 687.3/17 = 37.5 SO IT WILL REQUIRE 37.5/2 = 18.74 MOLS CO2.
mols CO2 available = 787.3/44 = 17.89 so yes, CO2 is the limiting reagent. The part I objected to was "18.74 mols in 1 NH3". The 18.74 mols CO2 is the mols CO2 that will be required to react with all of the NH3 and since that is higher than the mols CO2 you have (17.89), then CO2 is the limiting reagent.
c. (10 points) Which of the two reactants should you use to calculate the theoretical yield (= the maximum amount
possible) of urea? Explain why.
UMMM I would calculate the NH3 because it is the larger one? why? I don't have a clue help?
You want to use the smaller one because that is what is determining how much urea you can obtain. The NH3 doesn't determine that since it is not the limiting reagent. The CO2 is the limiting reagent and it is the one that determines how much urea you get. Said another way the amount of urea you obtain is determined by the mols CO2 you have so that is the maximum amount of urea that can be obtained under the circumstances.
Let me show you how that works.
If you use NH3 the mols NH3 = 37.5 so you can produce 37.5/2 = 18.7 or mols urea. How many grams is that? 18.7 x 60.1 = about 1126 g urea.
Now, using CO2, there are 17.89 mols CO2 and you can get 17.89 mols urea. That is 17.89 x 60.1 = about 1075g. So one reactant (the NH3) will produce 1126 g urea if ALL OF IT REACTS with an unlimited amount of CO2. You can get 1075 g urea if you use ALL OF THE CO2 and an unlimited supply of NH3. So how much can you get if you use them together. No more than the smaller amount will produce.