Suppose now that you wanted to determine the density of a small crystal to confirm that it is graphite. From the literature, you know that graphite has a density of 2.25 g/cm^3. How would you prepare 20.0 mL of the liquid mixture having that density from pure samples of CHCl3 (d = 1.492 g/mL) and CHBr3 (d = 2.890 g/mL)? (Note: 1 mL = 1 cm^3.)

The volume of first and second compound are 9.15 ml and 10.85 ml.

Explanation:

Given that,

Density of graphite = 2.25 g/cm³

Volume of mixture = 20.0 mL

Density of first compound = 1.492 g/ml

Density of second compound = 2.890 g/ml

Let the volume of first mixture = x

The volume of second mixture = (20-x)....(I)

We need to calculate the volume of first compound

Using formula of  density of mixture

Where, = volume of first compound

= volume of second compound

=density of first compound

= density of first compound

Put the volume into the formula

We need to calculate the volume of second compound

Using equation (I)

Put the value of x

Hence, The volume of first and second compound are 9.15 ml and 10.85 ml.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"