Practical Mechanisms

Question 1

Purifying Orgnanic Products

Answer 1

Page 242 in textbook

Question 2

Drying organic product

Answer 2

Page 243 in textbook

Question 3

Making a standard solution method. (6 Marks)

Answer 3

widjaw

Question 4

How to determine enthalpy change of reaction
e.g. between Zn and CuSO4.
Mechanism:
(6 Marks)

Answer 4

Safety:
Zinc dust is flammable
copper sulfate is harmful is consumed
- you should therefore:
- wear safety goggles
- gloves
- lab coat at all times

Method:
1. Measure out 25cm3 of Copper sulphate solution using a 100cm3 measuring cylinder
transfer the solution into a polystyrene cup, inside a 250cm3 beaker
2. weigh out approx. x grams of zinc powder in the weighing bottle
3. put the thermometer through the hole in the lid so that the thermometer is in the solution
- meausure the initial temp. of the solution
4. measure and record the initial temperature of the solution (nearest degree C)
5. Add the zinc powder to the polystyrene cup and stir the mixture gently
6. measure and record the max. temp. reached

Results:

1. Initial, max temp of solution can be used to measure temp change of solution
2. use Q = mcAt to measure the enthalpy change
3. Calculate the amount, in moles, of CuSO4 reacted
4. work out enthalpy change per mole/g of CuSO4 reacted