January Mock Mistakes

Question 1

A student prepares a standard solution of 250.0cm3 of a standard solution of 0.150moldm-3 of (Ba(OH)2) for the titration.
The student is provided with solid Ba(OH)2 and usual laboratory apparatus and equipment.
Describe how the student would prepare the standard solution, giving full details of quantities, apparatus and method.

Answer 1

Calculations:

1. Work out mass of Ba(OH)2 using n = m/Mr
2. Mass comes out as 6.42g (3s.f)

Method:

1. Dissolve the 6.42g of Ba(OH)2 in 50cm3 of distilled water in a beaker (use a stirring rod)
2. Transfer into a volumetric flask
3. Wash beaker, stirring rod and funnel and pour washings into volumetric flask
4. Make solution up to 250cm3 using distilled water
5. Invert the flask several times to endure it’s mixed