Colligative Properties Flashcards
(9 cards)
The main purpose for the Colligative Properties experiment is to:
to identify an unknown acid dissolved in stearic acid through the colligative property of freezing point depression.
A colligative property depends upon the number of solute particles present and is not dependent upon the specific chemical identity of the solute.
True
The following freezing temperatures will be recorded in this lab. (Select all that apply)
The solution of stearic acid with an unknown fatty acid
The pure solvent, stearic acid
Describe the expected experimental apparatus you will use to determine the freezing point of the fatty acid samples.
The smaller test tube must be wrapped in a paper towel and fitted into the larger test tube. The large test tube is secured on the ring stand using a clamp, higher up than the beaker of water on the hot plate and away from any rising steam. An alcohol thermometer is placed in the small test tube to monitor the fatty acid temperature. depression.
The unknown will be added to the same stearic acid sample used in Part C.
True
At different elevations, compounds can have different van’t hoff factors.
No, it depends on the identity of the solute.
Rank the following solutes from smallest to largest observed freezing point depression in water (Kf = 1.86 °C/m, with m = molal)
A: 0.8 m LiCl
B: 0.5 m MgCl2
C: 0.2 m CuCl2
D: 1.2 m acetone
C<D<B<A
A solution containing 20.0 g of an unknown non-electrolyte liquid and 110.0 g water has a freezing point of -1.32 °C. Given Kf = 1.86°C/m for water, the molar mass of the unknown liquid is:
256 g/mol
Important PPE/attire for this lab includes: (Select all that apply)
Lab coat (worn buttoned at all times in the lab space)
Shoes that fully enclose feet; pants/skirt and socks that overlap to fully cover legs and ankles
Gloves (worn at all times when manipulating the experimental set-up)
Goggles (worn over eyes at all times in the lab space)
