General Chemistry II - chem1412, HCC
1/30/2024
Pre lab 2
Procedure:
Measure 50ml of distilled water with a graduated cylinder, and
pour it into a 100-150 ml beaker. Attach the thermometer to a
test tube with a rubber band. Suspend the test tube/
thermometer into the water such that the thermometer bulb is
immersed in the water. Secure them with a test tube clamp.
Begin heating the water on a hot plate, recording the
temperature every 30 seconds until it boils. Record the final
boiling point and time. Next ,we measure 5g of unknown
solute, which is a binary salt. Then measure another 50 ml
distilled water. Mix the solute with water until it is fully
dissolved. Heat the solution, and record the boiling
temperature and time to achieve it, every 30 seconds.
Pre lab questions:
1) Four colligative properties are boiling point elevation, freezing
point depression, osmotic pressure, vapor pressure depression.
Upon addition of a solute to a solution,
Boiling point elevation: elevated
Freezing point depression: depressed
Osmotic pressure: elevated
Vapor pressure depression: depressed
2) Molality is defined as the total moles of a solute contained in a
kilogram of solvent.
3)a) BaCl2 - 3
b) NaNO3 – 2
c) C6H5O6 - 1
d) HCl - 2
e)Na3PO4 - 4