The density of acetic anhydride is 1.08 g/mL. Calculate the mass (in grams) of acetic anhydride present in 2.41 mL of acetic anhydride.  The density of acetic anhydride (C4H6O3) is 1.08 g/mL. Calculate the moles of acetic anhydride present in 3.39 mL of acetic anhydride. ÂÂ
The density of acetic anhydride is 1.08 g/mL. Calculate the mass (in grams) of acetic anhydride present in 2.41 mL of acetic anhydride.
The Correct Answer and Explanation is :
To calculate the mass of acetic anhydride in grams given its density, we use the relationship:
[
\text{Density} = \frac{\text{Mass}}{\text{Volume}}
]
Rearranging this equation to solve for mass:
[
\text{Mass} = \text{Density} \times \text{Volume}
]
Given data:
- Density of acetic anhydride = 1.08 g/mL
- Volume = 2.41 mL
Substitute these values into the equation:
[
\text{Mass} = 1.08 \, \text{g/mL} \times 2.41 \, \text{mL} = 2.60 \, \text{g}
]
So, the mass of 2.41 mL of acetic anhydride is 2.60 grams.
To calculate the moles of acetic anhydride in 3.39 mL:
- Step 1: Calculate the mass of acetic anhydride in grams.
Using the same formula for mass (Density × Volume):
[
\text{Mass} = 1.08 \, \text{g/mL} \times 3.39 \, \text{mL} = 3.67 \, \text{g}
]
- Step 2: Convert mass to moles.
To convert from grams to moles, we use the molar mass of acetic anhydride (C₄H₆O₃). The molar mass is calculated by adding the atomic masses of its constituent elements:
- Carbon (C) = 12.01 g/mol
- Hydrogen (H) = 1.008 g/mol
- Oxygen (O) = 16.00 g/mol
[
\text{Molar mass of C₄H₆O₃} = (4 \times 12.01) + (6 \times 1.008) + (3 \times 16.00) = 48.04 + 6.048 + 48.00 = 102.088 \, \text{g/mol}
]
Now, to find the number of moles (n), we divide the mass (in grams) by the molar mass (in g/mol):
[
n = \frac{\text{Mass}}{\text{Molar mass}} = \frac{3.67 \, \text{g}}{102.088 \, \text{g/mol}} \approx 0.036 \, \text{mol}
]
Final answers:
- The mass of acetic anhydride in 2.41 mL is 2.60 g.
- The moles of acetic anhydride in 3.39 mL is approximately 0.036 mol.
This process involves using the concept of density to calculate mass, followed by using the molar mass to convert mass into moles, which are essential conversions in chemistry for understanding quantities of substances involved in chemical reactions.