Question

Suppose now that you wanted to determine the density of a small crystal to confirm that it is boron. From the literature, you know that boron has a density of 2.34 g/cm^3. How would you prepare 20.0 mL of the liquid mixture having that density from pure samples of CHCI3 ( d= 1.492 g/mL) and CHBr3( d= 2.890 g/mL)? (Note: 1 mL = 1 cm^3.)

Answer 1

Answer:

the volume of  CHCI3 = 7.87 ml

the volume of  CHBr3 = 12.13 ml

Explanation:

From the given information:

We all know that 1 g/cm^3 = 1 g/ml

The density of boron = 2.34 g/ml

The Volume of the liquid mixture  = 20 ml

Recall that:

Density = mass/volume

Mass = Density × Volume

Mass = 2.34 g/ml × 20 ml

Mass = 46.8 g

Suppose the volume of  CHCI3 be Y and the Volume of CHBr3 be 20 - Y

Then :

Y (1.492) + 20-Y(2.890) = 46.8

1.492Y + 57.8 - 2.890Y = 46.8

- 1.398 Y = -11

Y = -11/ - 1.398

Y = 7.87 ml

Therefore, the volume of CHCI3  7.87 ml

the volume of  CHBr3 = 20 - Y

= 20 - 7.87

= 12.13 ml