The density of acetic anhydride is 1.08 g/ml. What is the mass of 2.00ml 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 :
To calculate the mass of acetic anhydride in a 2.00 mL sample and the number of moles in a 500.0 mL bottle, we need to use the given density and the molar mass of acetic anhydride.
1. Mass of Acetic Anhydride in 2.00 mL
We are given:
- Density of acetic anhydride = 1.08 g/mL
- Volume = 2.00 mL
The formula to calculate mass from density is: Mass=Density×Volume\text{Mass} = \text{Density} \times \text{Volume}
Substituting the known values: Mass=1.08 g/mL×2.00 mL=2.16 g\text{Mass} = 1.08 \, \text{g/mL} \times 2.00 \, \text{mL} = 2.16 \, \text{g}
So, the mass of 2.00 mL of acetic anhydride is 2.16 g.
2. Moles of Acetic Anhydride in 500.0 mL
Next, we need to find the number of moles in a 500.0 mL bottle. To do this, we must first calculate the mass of acetic anhydride in 500.0 mL, then convert that mass to moles.
- Volume = 500.0 mL
- Density = 1.08 g/mL
Using the mass formula again: 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}
Now, to calculate moles, we use the molar mass of acetic anhydride, which is 102.09 g/mol. The formula to find moles is: Moles=MassMolar Mass\text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}}
Substituting the values: Moles=540.0 g102.09 g/mol≈5.29 mol\text{Moles} = \frac{540.0 \, \text{g}}{102.09 \, \text{g/mol}} \approx 5.29 \, \text{mol}
So, there are approximately 5.29 moles of acetic anhydride in a 500.0 mL bottle.
Explanation:
- Density describes how much mass is present in a given volume of substance. Using the density equation, we first calculate the mass of acetic anhydride in a specific volume.
- To convert mass to moles, we use the molar mass, which tells us how many grams of a substance are in one mole.
- By applying these two calculations, we can determine the mass in grams for any volume and the number of moles for that mass based on the substance’s molar mass.