The density of acetic anhydride is 1.08 g/ml. What is the mass of 2.00 ml of acetic anhydride? How many moles of acetic anhydride are present in a 500.0 ml bottle of acetic anhydride
The Correct Answer and Explanation is:
Correct Answers:
- Mass of 2.00 mL of acetic anhydride:
Mass=Density×Volume=1.08 g/mL×2.00 mL=2.16 g\text{Mass} = \text{Density} \times \text{Volume} = 1.08 \, \text{g/mL} \times 2.00 \, \text{mL} = \boxed{2.16 \, \text{g}}Mass=Density×Volume=1.08g/mL×2.00mL=2.16g
- Moles in 500.0 mL of acetic anhydride:
First, calculate the mass:Mass=1.08 g/mL×500.0 mL=540.0 g\text{Mass} = 1.08 \, \text{g/mL} \times 500.0 \, \text{mL} = 540.0 \, \text{g}Mass=1.08g/mL×500.0mL=540.0g
Molar mass of acetic anhydride (C₄H₆O₃):(4×12.01)+(6×1.008)+(3×16.00)=102.09 g/mol(4 \times 12.01) + (6 \times 1.008) + (3 \times 16.00) = 102.09 \, \text{g/mol}(4×12.01)+(6×1.008)+(3×16.00)=102.09g/molMoles=MassMolar Mass=540.0 g102.09 g/mol≈5.29 mol\text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}} = \frac{540.0 \, \text{g}}{102.09 \, \text{g/mol}} \approx \boxed{5.29 \, \text{mol}}Moles=Molar MassMass=102.09g/mol540.0g≈5.29mol
Explanation
Understanding the relationship between density, volume, and mass is essential in chemical calculations. Density is defined as mass per unit volume and is expressed in grams per milliliter (g/mL). To determine the mass of a liquid when density and volume are known, multiplication of these two quantities gives the desired value.
In this case, acetic anhydride has a density of 1.08 g/mL. When 2.00 mL of this compound is measured, the mass is obtained by multiplying the volume by the density, resulting in 2.16 grams.
To determine the number of moles in a specific volume of acetic anhydride, the process starts with calculating the total mass in grams. A 500.0 mL bottle contains 540.0 grams of the liquid based on its density. The number of moles is calculated by dividing this mass by the molar mass of the substance.
Acetic anhydride, with the molecular formula C₄H₆O₃, has a molar mass of approximately 102.09 g/mol. This is calculated using the atomic masses of carbon (12.01 g/mol), hydrogen (1.008 g/mol), and oxygen (16.00 g/mol). By dividing the total mass (540.0 g) by the molar mass (102.09 g/mol), the resulting value indicates that the bottle contains approximately 5.29 moles of acetic anhydride.
This approach is commonly used in laboratory and industrial settings to convert between volume, mass, and moles, ensuring accurate measurements and effective reagent preparation in chemical processes.
