A solution that contains #"13.2 g"# of solute in #"250 g"# of #"CCl"_4# freezes at #-33^@ "C"#. What is the FW of the solute? #T_f^"*"# of #"CCl"_4# is #-22.8^@ "C"# and its #K_f = -29.8^@ "C/m"#.

Answer 1
#M = "154.26 g/mol"#

You can think of this as just an extension of freezing point depression into solvents that aren't water. Thus, refer to the freezing point depression equation:

#bb(DeltaT_f = T_f - T_f^"*" = -iK_fm)#,

where:

Now, the question hasn't specified whether the solute is a nonelectrolyte. However, since #"CCl"_4# is nonpolar, it dissolves a solute that is also nonpolar, which is not likely to dissociate in solution, so #i = 1#.

The molality is what we can end up using to get the formula mass ("FW") of the solute, so we would solve for the molality.

#m = -(DeltaT_f)/(iK_f)#
#= -(-33^@ "C" - (-22.8^@ "C"))/((1) cdot 29.8^@ "C/m")#
#= 0.342# #"mols/kg"#
Knowing that we have #"250 g"# of the solvent, or #"0.250 kg"#, we therefore have:
#"0.342 mols"/"kg" = "0.0856 mols"/"0.250 kg"#
As a result, we have #"0.0856 mols"# of solute for every #"13.2 g"# of solute. Therefore, the formula mass is given by:
#color(blue)(M) = "13.2 g"/("0.0856 mol") = color(blue)("154.26 g/mol")#
Sign up to view the whole answer

By signing up, you agree to our Terms of Service and Privacy Policy

Sign up with email
Answer 2

The formula weight (FW) of the solute is 260.6 g/mol.

Sign up to view the whole answer

By signing up, you agree to our Terms of Service and Privacy Policy

Sign up with email
Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

Not the question you need?

Drag image here or click to upload

Or press Ctrl + V to paste
Answer Background
HIX Tutor
Solve ANY homework problem with a smart AI
  • 98% accuracy study help
  • Covers math, physics, chemistry, biology, and more
  • Step-by-step, in-depth guides
  • Readily available 24/7