Analysis

Question 1

What would we use the melting point for?

Answer 1

To help identify a product and how pure the product is

Question 2

Why do we need to record the temperature for the start and end of melting?

Answer 2

The range indicates how impure the sample is, a large melting range means a product has more impurities

Question 3

between what range will a pure substance melt within?

Answer 3

0.5oC of true melting point

Question 4

Describe how to make a standard solution from a solid

Answer 4

1. weigh the required mass of solid with weighing boat
2. pour 100cm^3 of deionised water into a 250cm^3 beaker, transfer the solute and weigh the boat to calculate the exact mass of solute added
3. Stir the mixture to ensure it fully dissolves
4. Transfer to a 250cm^3 volumetric flask, adding the washings of the beaker and stirring rod as well.
5. Fill to within 1cm of the mark on the neck and use a dropping pipette to bring up to 250cm^3 while looking at it at eye level
6. Place the stopper in and invert it shaking thoroughly to make a homogenous mixture