Answer:
Autumn is one of the four basic seasons of the year in the temperate climate zone. It is characterized by moderate air temperatures with a decreasing daily average, and relatively high annual precipitation. The climate autumn is the period of the year in which the average daily air temperature ranges around 10° C.
Astronomical fall begins at the fall equinox and lasts until the winter solstice, which roughly means in the southern hemisphere between March 23 and June 22 (sometimes these dates are a day earlier or a day later, and in a leap year they may be additionally retracted one day). During astronomical autumn, the day time of the day is shorter than the night time, and moreover, with each successive day of the day it decreases and night increases.
In a laboratory synthesis, a student begins with 2.90 mL of acetic anhydride (density=1.08gml−1) and 1.23 g of salicylic acid. Once the reaction is complete, the student collects 1.24 g of aspirin.
1. Determine the theoretical yield of aspirin for the reaction. Express your answer using three significant figures.
2. Determine the percent yield of aspirin for the reaction. Express your answer using three significant figures.
Answer:
1.- Theoretical yield is 1.64 g of aspirin
2.- %Yield is 75.6%
Explanation:
The theoretical yield of aspirin could be calculated by the molar relation between anhydride acetic and salicylic acid which is 1:1. It means that the reaction of one mole of anhydride acetic with one mole of salicylic acid will produce 1 mole of aspirin and one mole of acetic acid.
It is possible to calculated the number of moles using moles=grams/molar mass. in the attached figure we can see the molar mass of each compound.
The number of moles of anhydride acetic can be calculated using the density and the volumen.
g=(1.08 g/mL)*(2.90 mL)=3.13 g of anhydride
moles= 3.13 g/(102.09 g/mol)= 0.031 moles of anhydride acetic
The same for salicylic acid and we have:
moles= 1.23g/ (138.12 g/mol)= 0.0090 moles of salicylic acid
There is not 1:1 relation between this two compounds because there is much more anhydride acetic than salicylic acid, so the reaction is limited by the 0.0090 moles of salicylic acid which produce 0.0090 moles of aspirin.
g= moles*molar mass
Theoretical yield of aspirin= (0.009 moles)*(182.13 g/mol)= 1.64 g
The percent yield of aspirin for the reaction can be calculated using the nex formula:
%yield= ((real yield)/(theoretical yield))*100
The real yield was 1.24 g of aspirin
%Yield=(1.24g/1.64)*100=75.6%
To determine the theoretical yield of aspirin, calculate the moles of acetic anhydride and salicylic acid, use the balanced equation to find the moles of aspirin, and convert to grams. The percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100.
To determine the theoretical yield of aspirin, we need to first calculate the number of moles of acetic anhydride and salicylic acid. Then, we use the balanced equation to find the number of moles of aspirin produced. Finally, we convert the moles of aspirin to grams using its molar mass. The percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100.
Step 1: Calculate the moles of acetic anhydride
2.90 mL × 1.08 g/mL = 3.132 g
Moles of acetic anhydride = mass / molar mass = 3.132 g / 102.09 g/mol = 0.0307 mol
Step 2: Calculate the moles of salicylic acid
Moles of salicylic acid = mass / molar mass = 1.23 g / 138.12 g/mol = 0.0089 mol
Step 3: Use the balanced equation to find the moles of aspirin produced
According to the balanced equation: 1 mol of acetic anhydride reacts with 1 mol of salicylic acid to produce 1 mol of aspirin
Since the moles of acetic anhydride and salicylic acid are the same, the moles of aspirin produced = 0.0089 mol
Step 4: Calculate the theoretical yield of aspirin in grams
The molar mass of aspirin is 180.16 g/mol
Theoretical yield of aspirin = moles of aspirin × molar mass of aspirin = 0.0089 mol × 180.16 g/mol = 1.61 g
Step 5: Calculate the percent yield of aspirin
Percent yield = (actual yield / theoretical yield) × 100
Percent yield = (1.24 g / 1.61 g) × 100 = 77.0%
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Answer:
The correct answer is CO2 diffuses passively out of the cell.
Explanation:
Carbon dioxide is one of the end product of cellular metabolism.CO2 is produced as waste material inside the body after cellular respiration.
Carbon dioxide is transported out from the body by passive diffusion process which helps the CO2 gas to move along the concentration gradient from high concentration region(body) to the low concentration region(atmosphere).
Thus CO2 ia being eliminated from our body.
Answer:
The majority of automobiles manufactured prior to 1994
Explanation:
their A/C systems. Since that time, several non-CFC refrigerants such as hydrofluorocarbons (HFCs) have been developed; and many more are in the development process