Questions: A chemist working as a safety inspector finds an unmarked bottle in a lab cabinet. A note on the door of the cabinet says the cabinet is used to store bottles of acetone, diethylamine, chloroform, carbon tetrachloride, and methyl acetate.
The chemist plans to try to identify the unknown liquid by measuring the density and comparing to known densities. First, from his collection of Material Safety Data Sheets (MSDS), the chemist finds the following information:
liquid density
acetone 0.79 g/cm^3
diethylamine 0.71 g/cm^3
chloroform 1.5 g/cm^3
carbon tetrachloride 1.6 g/cm^3
methyl acetate 0.93 g/cm^3
Next, the chemist measures the volume of the unknown liquid as 0.939 L and the mass of the unknown liquid as 663.8.
Transcript text: A chemist working as a safety inspector finds an unmarked bottle in a lab cabinet. A note on the door of the cabinet says the cabinet is used to store bottles of acetone, diethylamine, chloroform, carbon tetrachloride, and methyl acetate.
The chemist plans to try to identify the unknown liquid by measuring the density and comparing to known densities. First, from his collection of Material Safety Data Sheets (MSDS), the chemist finds the following information:
| liquid | density |
|--------|---------|
| acetone | $0.79 \frac{\mathrm{g}}{\mathrm{cm}^{3}}$ |
| diethylamine | $0.71 \frac{\mathrm{g}}{\mathrm{cm}^{3}}$ |
| chloroform | $1.5 \frac{\mathrm{g}}{\mathrm{cm}^{3}}$ |
| carbon tetrachloride | $1.6 \frac{\mathrm{g}}{\mathrm{cm}^{3}}$ |
| methyl acetate | $0.93 \frac{\mathrm{g}}{\mathrm{cm}^{3}}$ |
Next, the chemist measures the volume of the unknown liquid as 0.939 L and the mass of the unknown liquid as 663.8.
Solution
Solution Steps
Step 1: Calculate the Density of the Unknown Liquid
To calculate the density of the unknown liquid, we use the formula:
$$\text{Density} = \frac{\text{Mass}}{\text{Volume}}$$
Given that the mass of the unknown liquid is 663.8 g and the volume is 939 cm^3,
the calculated density is 0.71 g/cm^3 after rounding to 2 decimal places.
Step 2: Compare the Calculated Density with Known Densities
We compare the calculated density with the known densities of possible liquids.
The calculated density closely matches the density of diethylamine, with a difference of 0 g/cm^3.
Final Answer:
The unknown liquid is likely diethylamine, based on its density.